Xu Zhao* Shi-Chong Qiao* Jun-Yu Shi Naoya Uemura Korenori Arai Hong-Chang Lai
Evaluation of the clinical and aesthetic outcomes of Straumannâ Standard Plus implants supported single crowns placed in non-augmented healed sites in the anterior maxilla: a 5–8 years retrospective study
Authors’ affiliations: Xu Zhao, Shi-Chong Qiao, Jun-Yu Shi, Hong-Chang Lai, Department of Oral and Maxillofacial Implantology, Shanghai 9th People’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China Naoya Uemura, Korenori Arai, Department of Oral Implantology, Osaka Dental University, Osaka, Japan
Key words: aesthetics outcome, dental implant, long term, pink aesthetic score, single tooth,
Corresponding author: Prof. Hong-Chang Lai Department of Oral and Maxillo-facial Implantology, Shanghai Ninth People’s Hospital, School of Medicine, Shanghai Jiaotong University, 639 Zhizaoju Road, Shanghai 200011, China. Tel.: +86 21 13501881537 Fax: +86 21 53073068 e-mail: [email protected]
Material and methods: According to the inclusion criteria, patients who had received a single
soft tissue recession, white aesthetic score Abstract Purpose: To evaluate the long-term aesthetic outcome of the single crowns supported by soft tissue level implants placed in healed sites in the anterior maxilla region via the pink aesthetic score (PES) and the white aesthetic score (WES). Straumannâ Standard Plus implant in the anterior maxilla at the Shanghai 9th People’s Hospital between 2005 and 2008 were invited for a re-examination based on a number of inclusion criteria and exclusion criteria. Clinical, radiographic and aesthetic outcomes (PES/WES) were assessed during their revisit at 5–8 years after crown placement. Results: Forty-five patients were enrolled in the study. All 45 implants were successfully integrated and most of the implants did not show signs of peri-implant disease at the time of the assessment. The marginal bone resorption was 1.10 0.92 mm. The mean total PES was 8.48 2.62 at the baseline, 9.57 2.37 at the 6–10 months revisit and 9.01 2.45 at the 5–8 years follow-up. The scores of the mesial and distal papillae increased significantly between the baseline and 6– 10 months follow-up, this improvement remained stable at the 5–8 years follow-up. The scores of soft tissue level, colour of the soft tissue, soft tissue texture and the alveolar process decreased significantly between the 6–10 months and 5-8 years revisits. The mean WES was 7.83 1.60 at the baseline and 7.72 1.43 at the 5–8 years revisit. There was no significant difference of the WES between the baseline and 5–8 years revisit. Conclusion: The possibility of spontaneous papillae regeneration after implant treatment and the long-term stability of the regenerated papillae were confirmed. However, recession of the facial soft tissue has been found. The incidence of the recession at thin biotype sites tended to be higher.
*Contribute equally Date: Accepted 24 November 2014 To cite this article: Zhao X, Qiao S-C, Shi J-Y, Uemura N, Arai K, Lai H-C. Evaluation of the clinical and aesthetic outcomes of Straumannâ Standard Plus implants supported single crowns placed in non-augmented healed sites in the anterior maxilla: a 5–8 years retrospective study. Clin. Oral Impl. Res. 27, 2016, 106–112 doi: 10.1111/clr.12540
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With a history of more than 40 years, dental implants treatment has achieved a high reputation due to the high success rate (Albrektsson et al. 1986). Nowadays, replacing missing teeth with implant-supported prostheses has become a regular treatment in dental practice. When a single missing tooth is replaced in the anterior maxilla with an implant, it is important to rebuild the appearance as well as the function of the missing counterpart. Both successful implant-supported restorations and the peri-implant soft and hard tissues are vital determinants which may affect
the short- and long-term aesthetic outcomes (Belser et al. 2004, 2009). For this reason, a fine assessment system is needed to evaluate the aesthetic outcome. The pink aesthetic score (PES) was introduced for the evaluation of peri-implant soft tissues by Furhauser et al. (2005) and modified by Belser as PES/WES (Belser et al. 2009). So far, a series of clinical studies have confirmed the suitability of PES/WES and PES index for the objective outcome assessment of the aesthetic dimension of anterior singletooth implants (Buser et al. 2011, 2013; Cosyn
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Zhao et al Long-term aesthetic outcomes evaluation
et al. 2011; Cosyn et al. 2013; Dierens et al. 2013; Gallucci et al. 2011; Hof et al. 2013; Raes et al. 2013). However, most of the studies were focused on the aesthetic outcomes of immediate implant placement after tooth extraction with only short-term following up (Buser et al. 2011; Cosyn et al. 2011, 2012; Cosyn et al. 2013). Studies with long-term data for aesthetic outcome evaluation in non-augmented healed sites of the anterior maxilla are still rare. Furthermore, although bone level implants with platform switching design were more prone to be used in the aesthetic zone in recent studies (Raes et al. 2013; Santing et al. 2013; Sanz et al. 2014), soft tissue level implants such as Straumannâ Standard/Standard Plus have been widely used in the aesthetic zone as a common practice in the past (Lai et al. 2008; Belser et al. 2009; Gu et al. 2014). Thus, it is a worthwhile subject to evaluate the aesthetic outcomes of the soft tissue level implants. In our previous studies, we have found the aesthetic outcome of soft tissue around the single-tooth implant had improved significantly at follow-up compared with baseline according to PES/WES assessments (Lai et al. 2008; Gu et al. 2014). However, the followup time of the previous studies was relatively short (6-24 months). Thus, long time followup is necessary to confirm the previous hypothesis and observations. The aim of the present retrospective study was to review the long-term soft tissue stability and the long-term aesthetic outcomes of single crowns supported by tissue level implants placed in non-augmented healed sites.
Material and methods (1). This retrospective study was based on data from periodontally healthy patients who were clinically re-examined 5– 8 years following single-implant treatment at the Department of Oral & Maxillo-facial Implantology, Shanghai 9th People’s Hospital. Patients were called by telephone for a re-examination as long as they met the following inclusion criteria according to their records. (2). Have at least one implant-supported single crown in the anterior maxilla region (13–23) with Straumannâ (Institute Straumann AG, Basel, Switzerland) Standard Plus implants placed between December 2005 and October 2008.
(3). Have had the tooth extraction at least 3 months before implant surgery. (4). Did not receive soft or hard tissue augmentation before or in conjunction with implant surgery. (5). Did not receive restorative treatment of the adjacent teeth. (6). Underwent conventional healing and loading protocol after implant surgery. (7). Have both neighbouring teeth and corresponding teeth in the mandible. In addition, the patients should have had (1). Photographs of the anterior teeth, the photos should have been taken right after crown placement and at the 6–10 months recall visit. (2). Radiographs of the implant-supported single crowns, the radiographs should have been taken right after crown placement. The exclusion criteria include: (1). Patients who do not fulfil the inclusion criteria. (2). Patients who refused to join the study. The protocol was approved by the Ethics Committee of Shanghai 9th People’s Hospital, China. All patients signed the information consent form Shanghai 9th People’s Hospital affiliated to Shanghai Jiao Tong University, School of Medicine before entering the study. Implant placement
The implant placement procedures were planned based on clinical and radiographic evaluation. During the surgeries, the midcrestal incision and intracrevicular incision were made following local articaine infiltration anaesthesia. No releasing incisions were made. After full-thickness flaps were elevated labially and palatally to expose the alveolar ridge, the implants were placed according to the standard surgical procedures defined by the manufacturer. In the cases included in the current study, no implant sites required soft tissue or hard tissue augmentation, all implant threads were fully covered by bone after insertion. All the implants were placed non-submerged. After surgery, antibiotics as amoxicillin (Xinya Co., Shanghai, China, 500 mg) and metronidazole (Xinyiwanxiang, Shanghai, China, 400 mg) were prescribed for oral administration. In addition, chlorhexidine mouth wash (0.12%) was prescribed for rinsing for 60 s five to six times a day for 14 days. Sutures were removed 7–10 days after surgery. Patients were not allowed to use any removable prostheses during the healing period.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Prosthetic phase
After a healing time of 10–16 weeks, the impressions were taken at the implant level. The Straumann SynOcta abutments were fixed on the implants with titanium screws. The abutment torques for fixation were approximately 25 Ncm. The porcelain (Ivoclar-Vivadent AG, Schaan, Lichtenstein) fused to noble metal (Heraeus-Kulzer Corporation, Hanau, Germany) crowns was fabricated. Crowns were cemented onto the abutments with HY-bond Glass-ionomer Cement (CX, Shofu INC, Tokyo, Japan). All the crowns were placed in occlusal contact, but out of articulation to prevent overload. Follow-up examinations Clinical examinations
The clinical examinations were performed at the 5–8 years follow-up. The following parameters were evaluated: modified plaque index (mPLI) and modified sulcus bleeding index (mSBI) were recorded at four sites (mesial, distal, buccal and palatal) around each implant-supported single crowns; periimplant probing depth was recorded by a periodontal probe (15 UNC/CP-11.5B Screening Color-Coded Probe, Hu-Friedy) at the four sites, where the recordings were made to the nearest millimetre; tissue biotype was assessed based on the criteria suggested by M€ uller (Muller et al. 2000). When the outline of the periodontal probe could be seen through the gingival tissue, the biotype would be defined as the thin biotype. Correspondingly, if the outline of the periodontal probe was invisible, the biotype could be defined as the thick biotype (Muller et al. 2000; Kan et al. 2003; Evans & Chen 2008). Mechanical complications such as chipping or facture of the porcelain as well as abutment screw loosening were also observed during the patients’ revisit. Radiographic examinations
As routine post-operative examination, periapical radiographs were taken for all the patients with the long-cone technique at the time when the crowns were cemented. And the latest radiographs were taken at the time of the last revisit. All of the radiographic films were scanned at 600 dpi with a scanner (HP Scanjet 5590 (L1910A), HP), and the marginal bone level was assessed with image analysis software (UTHSCSA Image Tool 3.00 for Windows, University of Texas Health Science Center). The distance between implant shoulder and first visible bone-to-implant contact (BID) was measured
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on the mesial and distal aspects. For each implant and each examination period, the values were calculated as the average of the obtained mesial and distal values. Calibration was conducted by comparing the radiographic distance with the exact distance between the implants threads and by comparing the radiographic diameter with the exact diameter of the implant. The marginal bone resorption was calculated as the difference of BID between the baseline and the last revisit. The radiographic readings were performed by one experienced examiner who was neither involved in the surgical nor prosthetic treatment of the patients. For both clinical and radiographic examinations, the recordings were repeated by the same clinician after an interval of 4 weeks to evaluate intra-examiner reproducibility.
ing PES total scores, WES total scores, single parameter of the PES &WES, probing depth, mPLI, mSBI and marginal bone resorption around the implants. Besides, the frequency distribution of the PES and WES (total score and single variables) was also calculated. The chi-square test was used to compare the impact of the tissue biotypes. The Wilcoxon signed ranks test was used to compare the changes of the PES and WES, whereas the kappa statistics were used to assess interexaminer reproducibility of aesthetic assessment. The intra-examiner reproducibility of the marginal bone resorption was tested via Wilcoxon signed ranks, for the data do not follow the normal distribution. The level of significance for all tests was P < 0.05. All analyses were performed using computer software (IBM SPSS statistics version 19.00, IBM, Chicago, IL, USA).
Aesthetic assessment
The clinical photographs of the patients were primarily used to assess the PES and WES. The photos were taken 1 h after cementation of the crowns (baseline), 6–10 months after crown placement and 5–8 years after crown placement. All the photos were taken by an experienced nurse with the same digital camera (Nikon D70, Nikon Medical Objective circular flash; Nikon Corporation, Tokyo, Japan). The photos were taken from different angles (occlusion view and front view), so that all of the critical points were revealed clearly in the photographs. Besides, at least one adjacent natural tooth on each side had to be visible well enough to ensure comparability. To examine the aesthetic outcomes objectively, the photos were critically analysed by two examiners to assess the pink aesthetic score (PES) and white aesthetic score (WES) independently. Both of the examiners have not been involved with the surgical and restorative operations. The PESs were based on seven parameters which had been introduced by Furhauser et al. (2005). And the WESs were based on five parameters which had been established by Belser et al. (2009). As proposed by Cosyn et al. (2013), for PES evaluation, a total score ≤7 was considered as aesthetic failure, whereas a total score ≥12 was considered as almost aesthetically perfect. And for WES evaluation, a total score of ≤5 was considered as aesthetic failure, while a total score of ≥9 was considered as almost aesthetically perfect. Statistical analysis
Mean values, medians and standard deviations were calculated for all the data, includ-
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Results Patient data
According to the inclusion criteria, 96 patients with implant-supported single crowns in the anterior maxilla were selected. However, only 54 patients were able to be reached by telephone calls. Among these 54 patients, six patients refused to join the study and three of them did not show up at the scheduled visit. At last, 45 systematically healthy patients (20 women and 25 men) and age 18–56 years (mean 38.6 years) were enrolled in this study. All the assessments were performed from July 2013 to January 2014. The follow-up periods for these patients were from 61 to 96 months, with a mean follow-up period of 74.1 months. The 45 osseointegrated implants presented a survival rate of 100% using the criteria of Albrektsson et al. (1986). Table 1 shows the dimensions of inserted implants. The implants were distributed in the locations of 27 central incisors, 10 lateral incisors and eight canines. Every implant placed had a diameter of 4.8 mm at the implant shoulder (Table 1).
Table 1. Number of implants with different length and diameter Diameter Length
3.3 mm
4.1 mm
Total
10 mm 12 mm Total
8 18 26
11 8 19
19 26 45
Straumann Dental Implant System, Institute Straumann AG, Basel, Switzerland.
Table 2. Peri-implant conditions (n = 45) Parameter
Mean/median
SD
mPLI mSBI PD (mm) Marginal bone resorption (mm)
0.62/0.50 0.65/0.50 3.79/4.00 1.10/1.00
0.56 0.58 0.88 0.92
N, number; mPLI, modified plaque index; mSBI, modified bleeding index; PD, probing depth.
Clinical and radiographic examinations
Table 2 shows the details of all the clinical examinations. None of the patients presented with suppuration of the peri-implant mucosa. Most of the patients presented with sufficient oral hygiene, the mean mPLI and mSBI were 0.62 (SD 0.56) and 0.65 (SD 0.58) during the re-examination. And the mean probing depth was 3.79 mm (SD 0.88). The mean marginal bone loss was 1.10 mm (SD 0.92 mm) with a range from 0.55 mm to 2.12 mm. The intraexaminer reproducibility of the clinical examinations was tested by Wilcoxon signed ranks and the P value of the test was 0.194 (P > 0.05). However, a total of 12 patients were diagnosed with peri-implant mucositis, while two others were diagnosed with periimplantitis. Thus, the biological complication rate was 31.1% (14/45). The patients with peri-implant diseases were treated with debridement and antiseptic mouth rinses. Further, oral health instruction was performed and the patients were asked to pay their revisit 2 weeks after the treatment. Most of the patients showed significant improvement after the debridement, when the photographs were taken. Totally 20 patients were classified as thin biotype, while the rest 25 patients were classified as thick biotype. During the last revisit, mid-facial mucosa recession was found in 13 patients (29.4%) in this study. Among these 13 patients, 9 of them were classified as thin biotype and the rest 4 patients belonged to thick-biotype group. Significant difference was found between the two groups via Pearson’s chi-square test (P = 0.033). Because of the lack of access to original crown dimension, exact measurements for the mid-facial mucosa recession could not be provided (Table 2). None of the singleimplant support restorations was found with abutment screw loosening, and two restorations were observed as porcelain chipping. Aesthetic assessment
At baseline, the mean PES and WES of the implant-supported single crowns were
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Zhao et al Long-term aesthetic outcomes evaluation
Table 3. Pink aesthetic score at baseline, 6–10 months revisit and 5–8 years revisit
Mesial papilla Distal papilla Soft tissue level Soft tissue outline Alveolar process deficiency Soft tissue colour Soft tissue texture Total scores
PES at Baseline*
PES at 6– 10 months*
PES at 5– 8 years*
Pvalue†
Pvalue‡
Pvalue§
0.98(0.62)/1.00 0.79(0.51)/1.00 1.23(0.64)/1.00 1.32(0.58)/1.00 1.30(0.53)/1.00
1.52(0.50)/1.50 1.14(0.49)/1.00 1.25(0.59)/1.00 1.24(0.57)/1.00 1.33(0.52)/1.00
1.58(0.50)/1.50 1.20(0.52)/1.00 1.07 (0.67)/1.00 1.17(0.56)/1.00 1.16(0.48)/1.00
0.000¶ 0.000¶ 0.557 0.083 0.305
0.125 0.334 0.002¶ 0.267 0.004¶
0.000¶ 0.000¶ 0.018¶ 0.037¶ 0.035¶
1.46(0.50)/1.50 1.40(0.54)/1.00 8.48(2.62)/9.00
1.53(0.50)/1.50 1.49(0.50)/1.50 9.57(2.37)/9.50
1.43(0.50)/1.50 1.39(0.49)/1.00 9.01(2.45)/9.00
0.196 0.106 0.000¶
0.022¶ 0.040¶ 0.000¶
0.855 0.857 0.013¶
PES, pink aesthetic score. * Mean (SD)/Medians. †Comparison between baseline and 6–10 months on 45 cases. ‡Comparison between 6–10 months and 5–8 years on 45 cases. §Comparison between baseline and 5–8 years on 45 cases. ¶P < 0.05.
8.48 2.62 and 7.83 1.60, respectively. The medians for PES and WES at the baseline were 9.00 and 8.00, respectively. The mean PES was 9.57 2.37 at 6–10 months revisit and 9.01 2.45 at the 5–8 years revisit. The medians for PES at the 6–10 months revisit were 9.50 and 9.00 at the 5–8 years revisit. The mean WES was 7.72 1.43 at the 5–8 years revisit. The median of the WES at 5–8 years revisit was 8.00. The detailed data are listed in Tables 3 and 4, which include means and standard deviations of PES and WES reported for single variable. Significant differences between baseline and 6–10 month follow-up were found in two of the seven parameters – mesial and distal papilla height. Consequently, significant difference was also found in the total scores between the baseline and the 6–10 month follow-up. Between the 6–10 months revisit and the 5–8 years revisit, significant differences were found in four of seven parameters (soft tissue level, alveolar process, soft tissue texture, soft tissue colour) and total scores. When compared the scores between the baseline and 5–8 years revisit, the significant differences were found in five of seven parameters and total scores. Among these five parameters, the mean values of mesial
and distal papilla were increased, whereas the mean values of soft tissue level, soft tissue outline and alveolar process decreased. None of the significant difference was found for WES between the baseline and the followups. The WES was 7.83 1.60 at baseline and 7.72 1.43 at 5–8 years follow-up (P = 0.648). The interexaminer agreement test was performed and Spearman correlation coefficient was calculated during the first evaluation, to weight the consistency coefficient of the two independent examiners. We found that the PES between the two examiners was well correlated with Cohen’s j coefficient of 0.533–0.776 (P < 0.001) for the seven independent parameters. The Spearman correlation coefficient of the total score between the two examiners was 0.775 (P < 0.01). For WES, the Cohen’s j coefficient was 0.707– 0.879 (P < 0.001) for the different parameters. The Spearman correlation coefficient of total score for WES between two examiners was 0.910 (P < 0.01). The Cohen’s j coefficient indicated the substantial interexaminer reliability for both WES and PES evaluation. The specific data are listed in Table 5. According to the index which had been proposed by Cosyn et al. (2011), nine cases (20.0%) were classified as (almost) aestheti-
Table 4. WES at baseline and 5–8 years revisit Tooth form Tooth volume Tooth colour Translucency Tooth texture Total
Baseline*
5–8 years*
P-value†
1.63(0.53)/2.00 1.68(0.47)/2.00 1.48(0.50)/1.50 1.58(0.50)/2.00 1.46(0.51)/1.00 7.83(1.60)/8.00
1.54(0.58)/2.00 1.58(00.52)/2.00 1.53(0.50)/1.50 1.60(0.49)/2.00 1.41(0.49)/1.00 7.72(1.43)/7.50
0.065 0.180 0.180 0.617 0.705 0.648
WES, white aesthetic score. * Mean (SD)/Median. †Comparison between baseline and 5–8 months on 45 cases. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Table 5. Interexaminer agreement test result of the pink aesthetic score and white aesthetic score Parameters
Kappa
P value
Mesial papilla Distal papilla Soft tissue level Soft tissue outline Alveolar process deficiency Soft tissue colour Soft tissue texture Tooth form Tooth volume Tooth colour Translucency Tooth texture
0.776 0.592 0.712 0.543 0.574
0.000 0.000 0.000 0.000 0.000
0.533 0.715 0.731 0.707 0.766 0.879 0.810
0.000 0.000 0.000 0.000 0.000 0.000 0.000
cally perfect, while 11 cases (24.4%) were classified as aesthetic failure at 5–8 years follow-up. For WES, 10 cases (22.2%) can be labelled as almost perfect, while four cases (11.8%) are counted as aesthetic failure. Among all cases, six cases (13.3%) were found with both almost perfect WES and PES.
Discussion The objective of the study was assessing the long-term clinical and aesthetic outcome of Straumannâ Standard Plus implants in the anterior maxilla placed in the non-augmented healed ridges. The results of current study confirmed favourable clinical and radiographic results for single restorations which supported by soft tissue level implants in anterior maxilla. At the last follow-up examination, all 45 implants were firmly osseointegrated. Furthermore, limited marginal bone resorption around the implants was found by the radiographic examination, representing the stability of the hard tissue in the mesial– distal aspects of the implants. In current study, the scores of mesial and distal papillae increased significantly during the 6–10 months follow-up. This finding agreed with the earlier studies which the papillae could regenerate in most cases with different implants and observation periods (Jemt 1997; Chang et al. 1999; Choquet et al. 2001; Priest 2003; Henriksson & Jemt 2004; Cardaropoli et al. 2006). Further, the scores for mesial and distal papillae height did not change significantly between 6–10 months and 5–8 years follow-ups, implying the longterm stability of the positive change of the papillae height had maintained after the remodelling and regeneration procedure. Several factors may play important roles in determining the height of the papillae and
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(b)
(a)
Fig. 1. Bone remodeling around the implant in mesial-distal direction A 35-year-old female with an implant-supported (Straumann 4.1 9 12 mm SP) crown on the left maxillary canine. The radiographs were taken at the baseline (a) and 89 months revisit (b), bone remodeling could be observed. Correspondingly stable papillae heights were shown in the photographs in Fig. 2.
the stability of the soft tissue around the dental implants in the anterior maxilla region. These include the three-dimensional position of the implants, the height of the alveolar bone of the adjacent teeth, the gingival biotype and the contours of the crowns (Grunder et al. 2005; Schropp et al. 2005; Nisapakultorn et al. 2010; Cosyn et al. 2013). Among all the factors, the alveolar bone levels at adjacent natural teeth seem mostly crucial in defining the height of the papillae (Kan et al. 2003; Evans & Chen 2008). Coysn and colleagues suggested that the original periodontal health status of the patients, the trauma caused by the surgical procedures such as vertical releasing incisions and the bone remodelling after the tooth extraction may affect the bone levels, thus causing the incomplete embrasure fill (Cosyn et al. 2013; Raes et al. 2013). In the current study, enrolled patients were without periodontal diseases; and the treatments were following standard flap elevation without releasing incisions. Therefore, the bone levels were relatively stable in the present study. This may explain why the PES of the mesial and distal papillae height remained stable (Figs 1 and 2). Further, as described in our previous studies, the advantage of one-piece non-submerged implants in maintaining ideal biological width could be another reason for the desirable results obtained from this study (Hermann et al. 2001; Lai et al. 2008; Gu et al. 2014).
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(a)
(b)
(c)
Fig. 2. The clinical photographs of the case presented in Fig. 1. Photographs were taken at the baseline (a), 6 months revisit (b) and 89 months revisit (c). Note the changes of the papillae height at the implant site and the lateral incisor.
However, four parameters (soft tissue level, the alveolar process deficiency, soft tissue colour and soft tissue texture) for PES were significantly decreased from the 6–10 months revisit to the 5–8 years revisit. The reasons
of decreased PES can be mostly attributed to the resorption of the facial bone wall and recession of mid-facial soft tissue. Because of lack of the data for the crown dimension at the baseline, exact measurements could not be provided. The changes of the mid-facial soft tissue were judged by comparing the changes on the photographs. Soft tissue biotype, thickness of the buccal bone wall and three-dimensional position of the implant were found as highly significant factors in determining the degree of the marginal tissue recession in various studies (Evans & Chen 2008; Nisapakultorn et al. 2010; Kan et al. 2011; Shi et al. 2014). In this study, mid-facial soft tissue recession was found in 13 patients, and most of the patients (n = 9) belonged to thin-scalloped soft tissue biotype. Thus, soft tissue biotype is considered as the main reason for the of the midfacial soft tissue recession. The minimal buccal bone width required to avoid vertical bone resorption has yet to be established. Some scholars suggested that when implants were placed at the healed sites in the aesthetic zone, an ideal buccal bone width of 1.8–2 mm should be ensured to achieve optimal biological and aesthetic outcomes (Spray et al. 2000; Buser et al. 2004; Grunder et al. 2005). Otherwise, soft tissue and hard tissue augmentation as guided bone regeneration or soft tissue grafting should be considered. In our practice, when the facial bone thickness was over 1.5 mm without obvious fenestration of the buccal bone wall, the GBR or soft tissue grafting would not be performed. The cases included in this study had not been passed through any augmentation procedure, so it could be assumed that facial bone thickness at the implant sites was around 1.5 mm in all cases. Hence, thin bone wall was also not the main factor contributing to the mid-facial soft tissue recession. As described in our previous study (Lai et al. 2008), for most of our cases, the implant shoulders were positioned about 1 mm palatal to the point of emergence at adjacent teeth and about 1 mm apical to the CEJ of the contralateral tooth, which means that the correct three-dimensional position of the implants had been achieved for most of the patients according to the criteria Buser et al. (2004) have suggested. But in some cases, especially when the implants were placed on the site with a reduced crestal height and thin biotype, the implant position had to be compromised. For these sites, the implants were frequently installed deeper than usual to prevent the colour of the
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Zhao et al Long-term aesthetic outcomes evaluation
implant shoulder from being disclosed via the thin soft tissue. However, it has been well documented that the level of implant platform was associated with the facial marginal mucosal level. The increased distance from the contact point to the implant platform might introduce a higher risk of soft tissue recession (Nisapakultorn et al. 2010). Besides, deep implant insertion may lead to a deep probing depth. Mombelli et al. (1987) have suggested that periodontal pathogens were frequently found at peri-implant sites with deep probing depth. The exit of such pathogens may cause an increased risk of peri-implant disease and mucosal recession, and these reasons may explain the soft tissue recession and relative deep probing depth in the current study. No significant difference was found between the two WES assessments in the present study. However, the final assessment scores showed a slight decrease compared with the scores at the baseline. Among all the parameters, the tooth form and tooth outline were somehow decreased, although this decrease did not reach statistical significance. This phenomenon could be attributed to the changes of the peri-implant soft tissue level of the restorations. This result is similar to other long-term clinical studies (Buser et al. 2013; Dierens et al. 2013).
Due to various reasons, no attempt was made to condition the soft tissues by means of a provisional crown in any of the patients at that time of the present study. The lack of the provisional crowns in the present study could also explain the relatively low PESs at the baseline when compared to the studies, in which cement or screw-retained provisional crowns were used (Belser et al. 2009; Buser et al. 2011, 2013; Raes et al. 2013). However, the PESs at the baseline are still comparable with the studies when the provisional crowns were not being used (Cosyn et al. 2013; Dierens et al. 2013). As a retrospective study, PES data of the present study were only based on three time points (baseline, 6–10 months and 5–8 years), the long observational span of the study could just show the rough trend of the soft tissue change. Also, the aesthetical assessment was solely based on photographs, which could not show the three-dimensional details of the peri-implant soft tissue. In future researches, the study casts should be taken to facilitate the assessment. Recommendation for future studies might be to perform a prospective designed study with the collection of all available data concerning the dimension changes of the both soft and hard tissue around the implants.
In conclusion, the results of the preceding study have shown that replacing the lost teeth in the maxillary anterior region with soft tissue level implants could achieve a favourable aesthetic result in the long term and that papilla level around single-tooth implants in the anterior maxilla can remain stable after 5–8 years. However, mid-facial recession could cause unfavourable aesthetic outcomes and the incidence of the recession at thin biotype sites tends to be higher than thick biotype sites.
anterior maxilla: anatomic and surgical considerations. The International Journal of Oral & Maxillofacial Implants 19(Suppl): 43–61. Buser, D., Wittneben, J., Bornstein, M.M., Grutter, L., Chappuis, V. & Belser, U.C. (2011) Stability of contour augmentation and esthetic outcomes of implant-supported single crowns in the esthetic zone: 3-year results of a prospective study with early implant placement postextraction. Journal of Periodontology 82: 342–349. Cardaropoli, G., Lekholm, U. & Wennstrom, J.L. (2006) Tissue alterations at implant-supported single-tooth replacements: a 1-year prospective clinical study. Clinical Oral Implants Research 17: 165–171. Chang, M., Wennstrom, J.L., Odman, P. & Andersson, B. (1999) Implant supported single-tooth replacements compared to contralateral natural teeth. Crown and soft tissue dimensions. Clinical Oral Implants Research 10: 185–194. Choquet, V., Hermans, M., Adriaenssens, P., Daelemans, P., Tarnow, D.P. & Malevez, C. (2001) Clinical and radiographic evaluation of the papilla level adjacent to single-tooth dental implants. A retrospective study in the maxillary anterior region. Journal of Periodontology 72: 1364–1371. Cosyn, J., De Bruyn, H. & Cleymaet, R. (2013) Soft tissue preservation and pink aesthetics around
single immediate implant restorations: a 1-year prospective study. Clinical Implant Dentistry and Related Research 15: 847–857. Cosyn, J.E.A., De Bruyn, H., Collys, K., Cleymaet, R. & De Rouck, T. (2011) Immediate single-tooth implants in the anterior maxilla: 3-year results of a case series on hard and soft tissue response and aesthetics. Journal of Clinical Periodontology 38: 746–753. Cosyn, J., Eghbali, A., De Bruyn, H., Dierens, M. & De Rouck, T. (2012) Single implant treatment in healing versus healed sites of the anterior maxilla: an aesthetic evaluation. Clinical Implant Dentistry and Related Research 14: 517–526. Dierens, M., de Bruecker, E., Vandeweghe, S., Kisch, J., de Bruyn, H. & Cosyn, J. (2013) Alterations in soft tissue levels and aesthetics over a 1622 year period following single implant treatment in periodontally-healthy patients: a retrospective case series. Journal of Clinical Periodontology 40: 311–318. Evans, C.D. & Chen, S.T. (2008) Esthetic outcomes of immediate implant placements. Clinical Oral Implants Research 19: 73–80. Furhauser, R., Florescu, D., Benesch, T., Haas, R., Mailath, G. & Watzek, G. (2005) Evaluation of soft tissue around single-tooth implant crowns:
Conflict of interest and source of funding statement None of the authors have conflict of interest. This study has been supported by National Basic Research Programme of China (2012CB933600). National Natural Science Foundation of China (31370962, 81470782).
Acknowledgements We would like to thank Xu He (Academy of Mathematics and Systems Science, Chinese academy of science) for statistics consultation. We also like to thank Ren Wang and Max Mao for English Proofreading.
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tional Journal of Oral & Maxillofacial Implants 26: 179–187. Kan, J.Y., Rungcharassaeng, K., Umezu, K. & Kois, J.C. (2003) Dimensions of peri-implant mucosa: an evaluation of maxillary anterior single implants in humans. Journal of Periodontology 74: 557–562. Lai, H.C., Zhang, Z.Y., Wang, F., Zhuang, L.F., Liu, X. & Pu, Y.P. (2008) Evaluation of soft-tissue alteration around implant-supported single-tooth restoration in the anterior maxilla: the pink esthetic score. Clinical Oral Implants Research 19: 560–564. Mombelli, A., van Oosten, M.A., Schurch, E., Jr & Land, N.P. (1987) The microbiota associated with successful or failing osseointegrated titanium implants. Oral Microbiology and Immunology 2: 145–151. Muller, H.P., Heinecke, A., Schaller, N. & Eger, T. (2000) Masticatory mucosa in subjects with different periodontal phenotypes. Journal of Clinical Periodontology 27: 621–626. Nisapakultorn, K., Suphanantachat, S., Silkosessak, O. & Rattanamongkolgul, S. (2010) Factors affecting soft tissue level around anterior maxillary single-tooth implants. Clinical Oral Implants Research 21: 662–670. Priest, G. (2003) Predictability of soft tissue form around single-tooth implant restorations. The International Journal of Periodontics & Restorative Dentistry 23: 19–27. Raes, F., Cosyn, J. & De Bruyn, H. (2013) Clinical, aesthetic, and patient-related outcome of immediately loaded single implants in the anterior maxilla: a prospective study in extraction sockets, healed ridges, and grafted sites. Clinical Implant Dentistry and Related Research 15: 819–835. Santing, H.J., Raghoebar, G.M., Vissink, A., den Hartog, L. & Meijer, H.J. (2013) Performance of
the straumann bone level implant system for anterior single-tooth replacements in augmented and nonaugmented sites: a prospective cohort study with 60 consecutive patients. Clinical Oral Implants Research 24: 941–948. Sanz, M., Cecchinato, D., Ferrus, J., Salvi, G.E., Ramseier, C., Lang, N.P. & Lindhe, J. (2014) Implants placed in fresh extraction sockets in the maxilla: clinical and radiographic outcomes from a 3-year follow-up examination. Clinical Oral Implants Research 25: 321–327. Schropp, L., Isidor, F., Kostopoulos, L. & Wenzel, A. (2005) Interproximal papilla levels following early versus delayed placement of single-tooth implants: a controlled clinical trial. The International Journal of Oral & Maxillofacial Implants 20: 753–761. Shi, J.Y., Wang, R., Zhuang, L.F., Gu, Y.X., Qiao, S.C. & Lai, H.C. (2014) Esthetic outcome of single implant crowns following type 1 and type 3 implant placement: a systematic review. Clinical Oral Implants Research 26: 768–774. Spray, J.R., Black, C.G., Morris, H.F. & Ochi, S. (2000) The influence of bone thickness on facial marginal bone response: stage 1 placement through stage 2 uncovering. Annals of Periodontology/The American Academy of Periodontology 5: 119–128.
Supporting Information Additional Supporting Information may be found in the online version of this article: Appendix S1. CONSORT 2010 checklist of information to include when reporting a randomised trial.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Evaluation of the clinical and aesthetic outcomes of Straumannâ Standard Plus implants supported single crowns placed in non-augmented healed sites in the anterior maxilla: a 5–8 years retrospective study
Authors’ affiliations: Xu Zhao, Shi-Chong Qiao, Jun-Yu Shi, Hong-Chang Lai, Department of Oral and Maxillofacial Implantology, Shanghai 9th People’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China Naoya Uemura, Korenori Arai, Department of Oral Implantology, Osaka Dental University, Osaka, Japan
Key words: aesthetics outcome, dental implant, long term, pink aesthetic score, single tooth,
Corresponding author: Prof. Hong-Chang Lai Department of Oral and Maxillo-facial Implantology, Shanghai Ninth People’s Hospital, School of Medicine, Shanghai Jiaotong University, 639 Zhizaoju Road, Shanghai 200011, China. Tel.: +86 21 13501881537 Fax: +86 21 53073068 e-mail: [email protected]
Material and methods: According to the inclusion criteria, patients who had received a single
soft tissue recession, white aesthetic score Abstract Purpose: To evaluate the long-term aesthetic outcome of the single crowns supported by soft tissue level implants placed in healed sites in the anterior maxilla region via the pink aesthetic score (PES) and the white aesthetic score (WES). Straumannâ Standard Plus implant in the anterior maxilla at the Shanghai 9th People’s Hospital between 2005 and 2008 were invited for a re-examination based on a number of inclusion criteria and exclusion criteria. Clinical, radiographic and aesthetic outcomes (PES/WES) were assessed during their revisit at 5–8 years after crown placement. Results: Forty-five patients were enrolled in the study. All 45 implants were successfully integrated and most of the implants did not show signs of peri-implant disease at the time of the assessment. The marginal bone resorption was 1.10 0.92 mm. The mean total PES was 8.48 2.62 at the baseline, 9.57 2.37 at the 6–10 months revisit and 9.01 2.45 at the 5–8 years follow-up. The scores of the mesial and distal papillae increased significantly between the baseline and 6– 10 months follow-up, this improvement remained stable at the 5–8 years follow-up. The scores of soft tissue level, colour of the soft tissue, soft tissue texture and the alveolar process decreased significantly between the 6–10 months and 5-8 years revisits. The mean WES was 7.83 1.60 at the baseline and 7.72 1.43 at the 5–8 years revisit. There was no significant difference of the WES between the baseline and 5–8 years revisit. Conclusion: The possibility of spontaneous papillae regeneration after implant treatment and the long-term stability of the regenerated papillae were confirmed. However, recession of the facial soft tissue has been found. The incidence of the recession at thin biotype sites tended to be higher.
*Contribute equally Date: Accepted 24 November 2014 To cite this article: Zhao X, Qiao S-C, Shi J-Y, Uemura N, Arai K, Lai H-C. Evaluation of the clinical and aesthetic outcomes of Straumannâ Standard Plus implants supported single crowns placed in non-augmented healed sites in the anterior maxilla: a 5–8 years retrospective study. Clin. Oral Impl. Res. 27, 2016, 106–112 doi: 10.1111/clr.12540
106
With a history of more than 40 years, dental implants treatment has achieved a high reputation due to the high success rate (Albrektsson et al. 1986). Nowadays, replacing missing teeth with implant-supported prostheses has become a regular treatment in dental practice. When a single missing tooth is replaced in the anterior maxilla with an implant, it is important to rebuild the appearance as well as the function of the missing counterpart. Both successful implant-supported restorations and the peri-implant soft and hard tissues are vital determinants which may affect
the short- and long-term aesthetic outcomes (Belser et al. 2004, 2009). For this reason, a fine assessment system is needed to evaluate the aesthetic outcome. The pink aesthetic score (PES) was introduced for the evaluation of peri-implant soft tissues by Furhauser et al. (2005) and modified by Belser as PES/WES (Belser et al. 2009). So far, a series of clinical studies have confirmed the suitability of PES/WES and PES index for the objective outcome assessment of the aesthetic dimension of anterior singletooth implants (Buser et al. 2011, 2013; Cosyn
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Zhao et al Long-term aesthetic outcomes evaluation
et al. 2011; Cosyn et al. 2013; Dierens et al. 2013; Gallucci et al. 2011; Hof et al. 2013; Raes et al. 2013). However, most of the studies were focused on the aesthetic outcomes of immediate implant placement after tooth extraction with only short-term following up (Buser et al. 2011; Cosyn et al. 2011, 2012; Cosyn et al. 2013). Studies with long-term data for aesthetic outcome evaluation in non-augmented healed sites of the anterior maxilla are still rare. Furthermore, although bone level implants with platform switching design were more prone to be used in the aesthetic zone in recent studies (Raes et al. 2013; Santing et al. 2013; Sanz et al. 2014), soft tissue level implants such as Straumannâ Standard/Standard Plus have been widely used in the aesthetic zone as a common practice in the past (Lai et al. 2008; Belser et al. 2009; Gu et al. 2014). Thus, it is a worthwhile subject to evaluate the aesthetic outcomes of the soft tissue level implants. In our previous studies, we have found the aesthetic outcome of soft tissue around the single-tooth implant had improved significantly at follow-up compared with baseline according to PES/WES assessments (Lai et al. 2008; Gu et al. 2014). However, the followup time of the previous studies was relatively short (6-24 months). Thus, long time followup is necessary to confirm the previous hypothesis and observations. The aim of the present retrospective study was to review the long-term soft tissue stability and the long-term aesthetic outcomes of single crowns supported by tissue level implants placed in non-augmented healed sites.
Material and methods (1). This retrospective study was based on data from periodontally healthy patients who were clinically re-examined 5– 8 years following single-implant treatment at the Department of Oral & Maxillo-facial Implantology, Shanghai 9th People’s Hospital. Patients were called by telephone for a re-examination as long as they met the following inclusion criteria according to their records. (2). Have at least one implant-supported single crown in the anterior maxilla region (13–23) with Straumannâ (Institute Straumann AG, Basel, Switzerland) Standard Plus implants placed between December 2005 and October 2008.
(3). Have had the tooth extraction at least 3 months before implant surgery. (4). Did not receive soft or hard tissue augmentation before or in conjunction with implant surgery. (5). Did not receive restorative treatment of the adjacent teeth. (6). Underwent conventional healing and loading protocol after implant surgery. (7). Have both neighbouring teeth and corresponding teeth in the mandible. In addition, the patients should have had (1). Photographs of the anterior teeth, the photos should have been taken right after crown placement and at the 6–10 months recall visit. (2). Radiographs of the implant-supported single crowns, the radiographs should have been taken right after crown placement. The exclusion criteria include: (1). Patients who do not fulfil the inclusion criteria. (2). Patients who refused to join the study. The protocol was approved by the Ethics Committee of Shanghai 9th People’s Hospital, China. All patients signed the information consent form Shanghai 9th People’s Hospital affiliated to Shanghai Jiao Tong University, School of Medicine before entering the study. Implant placement
The implant placement procedures were planned based on clinical and radiographic evaluation. During the surgeries, the midcrestal incision and intracrevicular incision were made following local articaine infiltration anaesthesia. No releasing incisions were made. After full-thickness flaps were elevated labially and palatally to expose the alveolar ridge, the implants were placed according to the standard surgical procedures defined by the manufacturer. In the cases included in the current study, no implant sites required soft tissue or hard tissue augmentation, all implant threads were fully covered by bone after insertion. All the implants were placed non-submerged. After surgery, antibiotics as amoxicillin (Xinya Co., Shanghai, China, 500 mg) and metronidazole (Xinyiwanxiang, Shanghai, China, 400 mg) were prescribed for oral administration. In addition, chlorhexidine mouth wash (0.12%) was prescribed for rinsing for 60 s five to six times a day for 14 days. Sutures were removed 7–10 days after surgery. Patients were not allowed to use any removable prostheses during the healing period.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Prosthetic phase
After a healing time of 10–16 weeks, the impressions were taken at the implant level. The Straumann SynOcta abutments were fixed on the implants with titanium screws. The abutment torques for fixation were approximately 25 Ncm. The porcelain (Ivoclar-Vivadent AG, Schaan, Lichtenstein) fused to noble metal (Heraeus-Kulzer Corporation, Hanau, Germany) crowns was fabricated. Crowns were cemented onto the abutments with HY-bond Glass-ionomer Cement (CX, Shofu INC, Tokyo, Japan). All the crowns were placed in occlusal contact, but out of articulation to prevent overload. Follow-up examinations Clinical examinations
The clinical examinations were performed at the 5–8 years follow-up. The following parameters were evaluated: modified plaque index (mPLI) and modified sulcus bleeding index (mSBI) were recorded at four sites (mesial, distal, buccal and palatal) around each implant-supported single crowns; periimplant probing depth was recorded by a periodontal probe (15 UNC/CP-11.5B Screening Color-Coded Probe, Hu-Friedy) at the four sites, where the recordings were made to the nearest millimetre; tissue biotype was assessed based on the criteria suggested by M€ uller (Muller et al. 2000). When the outline of the periodontal probe could be seen through the gingival tissue, the biotype would be defined as the thin biotype. Correspondingly, if the outline of the periodontal probe was invisible, the biotype could be defined as the thick biotype (Muller et al. 2000; Kan et al. 2003; Evans & Chen 2008). Mechanical complications such as chipping or facture of the porcelain as well as abutment screw loosening were also observed during the patients’ revisit. Radiographic examinations
As routine post-operative examination, periapical radiographs were taken for all the patients with the long-cone technique at the time when the crowns were cemented. And the latest radiographs were taken at the time of the last revisit. All of the radiographic films were scanned at 600 dpi with a scanner (HP Scanjet 5590 (L1910A), HP), and the marginal bone level was assessed with image analysis software (UTHSCSA Image Tool 3.00 for Windows, University of Texas Health Science Center). The distance between implant shoulder and first visible bone-to-implant contact (BID) was measured
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on the mesial and distal aspects. For each implant and each examination period, the values were calculated as the average of the obtained mesial and distal values. Calibration was conducted by comparing the radiographic distance with the exact distance between the implants threads and by comparing the radiographic diameter with the exact diameter of the implant. The marginal bone resorption was calculated as the difference of BID between the baseline and the last revisit. The radiographic readings were performed by one experienced examiner who was neither involved in the surgical nor prosthetic treatment of the patients. For both clinical and radiographic examinations, the recordings were repeated by the same clinician after an interval of 4 weeks to evaluate intra-examiner reproducibility.
ing PES total scores, WES total scores, single parameter of the PES &WES, probing depth, mPLI, mSBI and marginal bone resorption around the implants. Besides, the frequency distribution of the PES and WES (total score and single variables) was also calculated. The chi-square test was used to compare the impact of the tissue biotypes. The Wilcoxon signed ranks test was used to compare the changes of the PES and WES, whereas the kappa statistics were used to assess interexaminer reproducibility of aesthetic assessment. The intra-examiner reproducibility of the marginal bone resorption was tested via Wilcoxon signed ranks, for the data do not follow the normal distribution. The level of significance for all tests was P < 0.05. All analyses were performed using computer software (IBM SPSS statistics version 19.00, IBM, Chicago, IL, USA).
Aesthetic assessment
The clinical photographs of the patients were primarily used to assess the PES and WES. The photos were taken 1 h after cementation of the crowns (baseline), 6–10 months after crown placement and 5–8 years after crown placement. All the photos were taken by an experienced nurse with the same digital camera (Nikon D70, Nikon Medical Objective circular flash; Nikon Corporation, Tokyo, Japan). The photos were taken from different angles (occlusion view and front view), so that all of the critical points were revealed clearly in the photographs. Besides, at least one adjacent natural tooth on each side had to be visible well enough to ensure comparability. To examine the aesthetic outcomes objectively, the photos were critically analysed by two examiners to assess the pink aesthetic score (PES) and white aesthetic score (WES) independently. Both of the examiners have not been involved with the surgical and restorative operations. The PESs were based on seven parameters which had been introduced by Furhauser et al. (2005). And the WESs were based on five parameters which had been established by Belser et al. (2009). As proposed by Cosyn et al. (2013), for PES evaluation, a total score ≤7 was considered as aesthetic failure, whereas a total score ≥12 was considered as almost aesthetically perfect. And for WES evaluation, a total score of ≤5 was considered as aesthetic failure, while a total score of ≥9 was considered as almost aesthetically perfect. Statistical analysis
Mean values, medians and standard deviations were calculated for all the data, includ-
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Results Patient data
According to the inclusion criteria, 96 patients with implant-supported single crowns in the anterior maxilla were selected. However, only 54 patients were able to be reached by telephone calls. Among these 54 patients, six patients refused to join the study and three of them did not show up at the scheduled visit. At last, 45 systematically healthy patients (20 women and 25 men) and age 18–56 years (mean 38.6 years) were enrolled in this study. All the assessments were performed from July 2013 to January 2014. The follow-up periods for these patients were from 61 to 96 months, with a mean follow-up period of 74.1 months. The 45 osseointegrated implants presented a survival rate of 100% using the criteria of Albrektsson et al. (1986). Table 1 shows the dimensions of inserted implants. The implants were distributed in the locations of 27 central incisors, 10 lateral incisors and eight canines. Every implant placed had a diameter of 4.8 mm at the implant shoulder (Table 1).
Table 1. Number of implants with different length and diameter Diameter Length
3.3 mm
4.1 mm
Total
10 mm 12 mm Total
8 18 26
11 8 19
19 26 45
Straumann Dental Implant System, Institute Straumann AG, Basel, Switzerland.
Table 2. Peri-implant conditions (n = 45) Parameter
Mean/median
SD
mPLI mSBI PD (mm) Marginal bone resorption (mm)
0.62/0.50 0.65/0.50 3.79/4.00 1.10/1.00
0.56 0.58 0.88 0.92
N, number; mPLI, modified plaque index; mSBI, modified bleeding index; PD, probing depth.
Clinical and radiographic examinations
Table 2 shows the details of all the clinical examinations. None of the patients presented with suppuration of the peri-implant mucosa. Most of the patients presented with sufficient oral hygiene, the mean mPLI and mSBI were 0.62 (SD 0.56) and 0.65 (SD 0.58) during the re-examination. And the mean probing depth was 3.79 mm (SD 0.88). The mean marginal bone loss was 1.10 mm (SD 0.92 mm) with a range from 0.55 mm to 2.12 mm. The intraexaminer reproducibility of the clinical examinations was tested by Wilcoxon signed ranks and the P value of the test was 0.194 (P > 0.05). However, a total of 12 patients were diagnosed with peri-implant mucositis, while two others were diagnosed with periimplantitis. Thus, the biological complication rate was 31.1% (14/45). The patients with peri-implant diseases were treated with debridement and antiseptic mouth rinses. Further, oral health instruction was performed and the patients were asked to pay their revisit 2 weeks after the treatment. Most of the patients showed significant improvement after the debridement, when the photographs were taken. Totally 20 patients were classified as thin biotype, while the rest 25 patients were classified as thick biotype. During the last revisit, mid-facial mucosa recession was found in 13 patients (29.4%) in this study. Among these 13 patients, 9 of them were classified as thin biotype and the rest 4 patients belonged to thick-biotype group. Significant difference was found between the two groups via Pearson’s chi-square test (P = 0.033). Because of the lack of access to original crown dimension, exact measurements for the mid-facial mucosa recession could not be provided (Table 2). None of the singleimplant support restorations was found with abutment screw loosening, and two restorations were observed as porcelain chipping. Aesthetic assessment
At baseline, the mean PES and WES of the implant-supported single crowns were
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Zhao et al Long-term aesthetic outcomes evaluation
Table 3. Pink aesthetic score at baseline, 6–10 months revisit and 5–8 years revisit
Mesial papilla Distal papilla Soft tissue level Soft tissue outline Alveolar process deficiency Soft tissue colour Soft tissue texture Total scores
PES at Baseline*
PES at 6– 10 months*
PES at 5– 8 years*
Pvalue†
Pvalue‡
Pvalue§
0.98(0.62)/1.00 0.79(0.51)/1.00 1.23(0.64)/1.00 1.32(0.58)/1.00 1.30(0.53)/1.00
1.52(0.50)/1.50 1.14(0.49)/1.00 1.25(0.59)/1.00 1.24(0.57)/1.00 1.33(0.52)/1.00
1.58(0.50)/1.50 1.20(0.52)/1.00 1.07 (0.67)/1.00 1.17(0.56)/1.00 1.16(0.48)/1.00
0.000¶ 0.000¶ 0.557 0.083 0.305
0.125 0.334 0.002¶ 0.267 0.004¶
0.000¶ 0.000¶ 0.018¶ 0.037¶ 0.035¶
1.46(0.50)/1.50 1.40(0.54)/1.00 8.48(2.62)/9.00
1.53(0.50)/1.50 1.49(0.50)/1.50 9.57(2.37)/9.50
1.43(0.50)/1.50 1.39(0.49)/1.00 9.01(2.45)/9.00
0.196 0.106 0.000¶
0.022¶ 0.040¶ 0.000¶
0.855 0.857 0.013¶
PES, pink aesthetic score. * Mean (SD)/Medians. †Comparison between baseline and 6–10 months on 45 cases. ‡Comparison between 6–10 months and 5–8 years on 45 cases. §Comparison between baseline and 5–8 years on 45 cases. ¶P < 0.05.
8.48 2.62 and 7.83 1.60, respectively. The medians for PES and WES at the baseline were 9.00 and 8.00, respectively. The mean PES was 9.57 2.37 at 6–10 months revisit and 9.01 2.45 at the 5–8 years revisit. The medians for PES at the 6–10 months revisit were 9.50 and 9.00 at the 5–8 years revisit. The mean WES was 7.72 1.43 at the 5–8 years revisit. The median of the WES at 5–8 years revisit was 8.00. The detailed data are listed in Tables 3 and 4, which include means and standard deviations of PES and WES reported for single variable. Significant differences between baseline and 6–10 month follow-up were found in two of the seven parameters – mesial and distal papilla height. Consequently, significant difference was also found in the total scores between the baseline and the 6–10 month follow-up. Between the 6–10 months revisit and the 5–8 years revisit, significant differences were found in four of seven parameters (soft tissue level, alveolar process, soft tissue texture, soft tissue colour) and total scores. When compared the scores between the baseline and 5–8 years revisit, the significant differences were found in five of seven parameters and total scores. Among these five parameters, the mean values of mesial
and distal papilla were increased, whereas the mean values of soft tissue level, soft tissue outline and alveolar process decreased. None of the significant difference was found for WES between the baseline and the followups. The WES was 7.83 1.60 at baseline and 7.72 1.43 at 5–8 years follow-up (P = 0.648). The interexaminer agreement test was performed and Spearman correlation coefficient was calculated during the first evaluation, to weight the consistency coefficient of the two independent examiners. We found that the PES between the two examiners was well correlated with Cohen’s j coefficient of 0.533–0.776 (P < 0.001) for the seven independent parameters. The Spearman correlation coefficient of the total score between the two examiners was 0.775 (P < 0.01). For WES, the Cohen’s j coefficient was 0.707– 0.879 (P < 0.001) for the different parameters. The Spearman correlation coefficient of total score for WES between two examiners was 0.910 (P < 0.01). The Cohen’s j coefficient indicated the substantial interexaminer reliability for both WES and PES evaluation. The specific data are listed in Table 5. According to the index which had been proposed by Cosyn et al. (2011), nine cases (20.0%) were classified as (almost) aestheti-
Table 4. WES at baseline and 5–8 years revisit Tooth form Tooth volume Tooth colour Translucency Tooth texture Total
Baseline*
5–8 years*
P-value†
1.63(0.53)/2.00 1.68(0.47)/2.00 1.48(0.50)/1.50 1.58(0.50)/2.00 1.46(0.51)/1.00 7.83(1.60)/8.00
1.54(0.58)/2.00 1.58(00.52)/2.00 1.53(0.50)/1.50 1.60(0.49)/2.00 1.41(0.49)/1.00 7.72(1.43)/7.50
0.065 0.180 0.180 0.617 0.705 0.648
WES, white aesthetic score. * Mean (SD)/Median. †Comparison between baseline and 5–8 months on 45 cases. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Table 5. Interexaminer agreement test result of the pink aesthetic score and white aesthetic score Parameters
Kappa
P value
Mesial papilla Distal papilla Soft tissue level Soft tissue outline Alveolar process deficiency Soft tissue colour Soft tissue texture Tooth form Tooth volume Tooth colour Translucency Tooth texture
0.776 0.592 0.712 0.543 0.574
0.000 0.000 0.000 0.000 0.000
0.533 0.715 0.731 0.707 0.766 0.879 0.810
0.000 0.000 0.000 0.000 0.000 0.000 0.000
cally perfect, while 11 cases (24.4%) were classified as aesthetic failure at 5–8 years follow-up. For WES, 10 cases (22.2%) can be labelled as almost perfect, while four cases (11.8%) are counted as aesthetic failure. Among all cases, six cases (13.3%) were found with both almost perfect WES and PES.
Discussion The objective of the study was assessing the long-term clinical and aesthetic outcome of Straumannâ Standard Plus implants in the anterior maxilla placed in the non-augmented healed ridges. The results of current study confirmed favourable clinical and radiographic results for single restorations which supported by soft tissue level implants in anterior maxilla. At the last follow-up examination, all 45 implants were firmly osseointegrated. Furthermore, limited marginal bone resorption around the implants was found by the radiographic examination, representing the stability of the hard tissue in the mesial– distal aspects of the implants. In current study, the scores of mesial and distal papillae increased significantly during the 6–10 months follow-up. This finding agreed with the earlier studies which the papillae could regenerate in most cases with different implants and observation periods (Jemt 1997; Chang et al. 1999; Choquet et al. 2001; Priest 2003; Henriksson & Jemt 2004; Cardaropoli et al. 2006). Further, the scores for mesial and distal papillae height did not change significantly between 6–10 months and 5–8 years follow-ups, implying the longterm stability of the positive change of the papillae height had maintained after the remodelling and regeneration procedure. Several factors may play important roles in determining the height of the papillae and
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(b)
(a)
Fig. 1. Bone remodeling around the implant in mesial-distal direction A 35-year-old female with an implant-supported (Straumann 4.1 9 12 mm SP) crown on the left maxillary canine. The radiographs were taken at the baseline (a) and 89 months revisit (b), bone remodeling could be observed. Correspondingly stable papillae heights were shown in the photographs in Fig. 2.
the stability of the soft tissue around the dental implants in the anterior maxilla region. These include the three-dimensional position of the implants, the height of the alveolar bone of the adjacent teeth, the gingival biotype and the contours of the crowns (Grunder et al. 2005; Schropp et al. 2005; Nisapakultorn et al. 2010; Cosyn et al. 2013). Among all the factors, the alveolar bone levels at adjacent natural teeth seem mostly crucial in defining the height of the papillae (Kan et al. 2003; Evans & Chen 2008). Coysn and colleagues suggested that the original periodontal health status of the patients, the trauma caused by the surgical procedures such as vertical releasing incisions and the bone remodelling after the tooth extraction may affect the bone levels, thus causing the incomplete embrasure fill (Cosyn et al. 2013; Raes et al. 2013). In the current study, enrolled patients were without periodontal diseases; and the treatments were following standard flap elevation without releasing incisions. Therefore, the bone levels were relatively stable in the present study. This may explain why the PES of the mesial and distal papillae height remained stable (Figs 1 and 2). Further, as described in our previous studies, the advantage of one-piece non-submerged implants in maintaining ideal biological width could be another reason for the desirable results obtained from this study (Hermann et al. 2001; Lai et al. 2008; Gu et al. 2014).
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(a)
(b)
(c)
Fig. 2. The clinical photographs of the case presented in Fig. 1. Photographs were taken at the baseline (a), 6 months revisit (b) and 89 months revisit (c). Note the changes of the papillae height at the implant site and the lateral incisor.
However, four parameters (soft tissue level, the alveolar process deficiency, soft tissue colour and soft tissue texture) for PES were significantly decreased from the 6–10 months revisit to the 5–8 years revisit. The reasons
of decreased PES can be mostly attributed to the resorption of the facial bone wall and recession of mid-facial soft tissue. Because of lack of the data for the crown dimension at the baseline, exact measurements could not be provided. The changes of the mid-facial soft tissue were judged by comparing the changes on the photographs. Soft tissue biotype, thickness of the buccal bone wall and three-dimensional position of the implant were found as highly significant factors in determining the degree of the marginal tissue recession in various studies (Evans & Chen 2008; Nisapakultorn et al. 2010; Kan et al. 2011; Shi et al. 2014). In this study, mid-facial soft tissue recession was found in 13 patients, and most of the patients (n = 9) belonged to thin-scalloped soft tissue biotype. Thus, soft tissue biotype is considered as the main reason for the of the midfacial soft tissue recession. The minimal buccal bone width required to avoid vertical bone resorption has yet to be established. Some scholars suggested that when implants were placed at the healed sites in the aesthetic zone, an ideal buccal bone width of 1.8–2 mm should be ensured to achieve optimal biological and aesthetic outcomes (Spray et al. 2000; Buser et al. 2004; Grunder et al. 2005). Otherwise, soft tissue and hard tissue augmentation as guided bone regeneration or soft tissue grafting should be considered. In our practice, when the facial bone thickness was over 1.5 mm without obvious fenestration of the buccal bone wall, the GBR or soft tissue grafting would not be performed. The cases included in this study had not been passed through any augmentation procedure, so it could be assumed that facial bone thickness at the implant sites was around 1.5 mm in all cases. Hence, thin bone wall was also not the main factor contributing to the mid-facial soft tissue recession. As described in our previous study (Lai et al. 2008), for most of our cases, the implant shoulders were positioned about 1 mm palatal to the point of emergence at adjacent teeth and about 1 mm apical to the CEJ of the contralateral tooth, which means that the correct three-dimensional position of the implants had been achieved for most of the patients according to the criteria Buser et al. (2004) have suggested. But in some cases, especially when the implants were placed on the site with a reduced crestal height and thin biotype, the implant position had to be compromised. For these sites, the implants were frequently installed deeper than usual to prevent the colour of the
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Zhao et al Long-term aesthetic outcomes evaluation
implant shoulder from being disclosed via the thin soft tissue. However, it has been well documented that the level of implant platform was associated with the facial marginal mucosal level. The increased distance from the contact point to the implant platform might introduce a higher risk of soft tissue recession (Nisapakultorn et al. 2010). Besides, deep implant insertion may lead to a deep probing depth. Mombelli et al. (1987) have suggested that periodontal pathogens were frequently found at peri-implant sites with deep probing depth. The exit of such pathogens may cause an increased risk of peri-implant disease and mucosal recession, and these reasons may explain the soft tissue recession and relative deep probing depth in the current study. No significant difference was found between the two WES assessments in the present study. However, the final assessment scores showed a slight decrease compared with the scores at the baseline. Among all the parameters, the tooth form and tooth outline were somehow decreased, although this decrease did not reach statistical significance. This phenomenon could be attributed to the changes of the peri-implant soft tissue level of the restorations. This result is similar to other long-term clinical studies (Buser et al. 2013; Dierens et al. 2013).
Due to various reasons, no attempt was made to condition the soft tissues by means of a provisional crown in any of the patients at that time of the present study. The lack of the provisional crowns in the present study could also explain the relatively low PESs at the baseline when compared to the studies, in which cement or screw-retained provisional crowns were used (Belser et al. 2009; Buser et al. 2011, 2013; Raes et al. 2013). However, the PESs at the baseline are still comparable with the studies when the provisional crowns were not being used (Cosyn et al. 2013; Dierens et al. 2013). As a retrospective study, PES data of the present study were only based on three time points (baseline, 6–10 months and 5–8 years), the long observational span of the study could just show the rough trend of the soft tissue change. Also, the aesthetical assessment was solely based on photographs, which could not show the three-dimensional details of the peri-implant soft tissue. In future researches, the study casts should be taken to facilitate the assessment. Recommendation for future studies might be to perform a prospective designed study with the collection of all available data concerning the dimension changes of the both soft and hard tissue around the implants.
In conclusion, the results of the preceding study have shown that replacing the lost teeth in the maxillary anterior region with soft tissue level implants could achieve a favourable aesthetic result in the long term and that papilla level around single-tooth implants in the anterior maxilla can remain stable after 5–8 years. However, mid-facial recession could cause unfavourable aesthetic outcomes and the incidence of the recession at thin biotype sites tends to be higher than thick biotype sites.
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Conflict of interest and source of funding statement None of the authors have conflict of interest. This study has been supported by National Basic Research Programme of China (2012CB933600). National Natural Science Foundation of China (31370962, 81470782).
Acknowledgements We would like to thank Xu He (Academy of Mathematics and Systems Science, Chinese academy of science) for statistics consultation. We also like to thank Ren Wang and Max Mao for English Proofreading.
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Supporting Information Additional Supporting Information may be found in the online version of this article: Appendix S1. CONSORT 2010 checklist of information to include when reporting a randomised trial.
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