Implant-Supported Single Crowns Replacing Congenitally Missing Maxillary Lateral Incisors: A 5-Year Follow-Up Marie Branzén, DDS;* Alf Eliasson, DDS, PhD;† Kristina Arnrup, DDS, PhD;‡ Farhan Bazargani, DDS, PhD§
ABSTRACT Background: Knowledge of the long-term survival of single implants in cases of congenitally missing lateral incisors in the maxilla is limited. Purpose: This retrospective study aimed to evaluate the 5-year survival of implants and implant-supported crowns (ISCs) and to assess the functional and aesthetic outcomes from the professional and patient perspectives. Materials and Methods: From a total of 46 patients with congenitally missing upper lateral incisors, 36 patients treated with 54 Brånemark® (Nobel Biocare AB, Göteborg, Sweden) implants and ISCs participated in the study. A clinical examination, California Dental Association (CDA) evaluation, and patient questionnaire were used to rate and compare the objective and subjective evaluations of the ISCs. Results: The survival of implants and ISCs was 100%. The CDA ratings were satisfactory for all ISCs, with 70% being rated excellent. The patient rating was also high for the overall satisfaction item, with 21 being completely satisfied and 14 fairly satisfied. However, 12 patients wished for the replacement of their ISCs. Logistic regression analysis indicated that a less optimal embrasure fill was the most discriminating factor though not statistically significant (p = .082). Conclusions: One-third of the patients wished for the replacement of their ISCs. Soft tissue adaptation seems to be an important factor for overall satisfaction. KEY WORDS: agenesis, dental implants, dental papillae, follow-up, patient satisfaction
INTRODUCTION
absence is more common bilaterally than unilaterally. Sex differences in prevalence have usually been found to be small with slightly more women than men affected.2,3 Genetic and environmental factors have been implicated in congenitally missing teeth, and recent studies have demonstrated the predominant role of genetics in the aetiology of this condition.4 Replacing the maxillary lateral incisors with implant-supported single-crown restorations is today a widely recognized method. As well as not harming the sound parts of the natural dentition, such restorations have the following advantages: (1) alveolar bone preservation; (2) enhancement of occlusal function; (3) enhanced appearance; (4) oral hygiene facilitation; and (5) long-term survival.1 The topography of the peri-implant mucosa in terms of the position of the soft tissue margin on the facial aspect of the implant-supported crown (ISC) and the degree of papilla fill in the embrasure spaces lateral to the crown are important factors affecting the aesthetic
Agenesis is the congenital lack of tooth buds. Agenesis of maxillary lateral incisors occurs in approximately 1% to 3% of the population in north-western Europe and is the most common missing tooth after the second premolar, excluding the third molars.1 This congenital
*Senior consultant, Specialist Clinic of Orthodontics, Public Dental Health Service, Karlstad, Sweden; †senior consultant, Department of Prosthetic Dentistry, Postgraduate Dental Education Center and School of Health and Medical Sciences, Örebro University, Örebro, Sweden; ‡associate professor, senior consultant, Dental Research Department, Public Dental Health Service, Örebro County Council and School of Health and Medical Sciences, Örebro University, Örebro, Sweden; §senior consultant, Department of Orthodontics, Postgraduate Dental Education Center, Örebro, Sweden Corresponding Author: Dr. Farhan Bazargani, Department of Orthodontics, Postgraduate Dental Education Center, P.O. Box 1126, SE- 701 11 Örebro, Sweden; e-mail: [email protected] © 2014 Wiley Periodicals, Inc. DOI 10.1111/cid.12233
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Clinical Implant Dentistry and Related Research, Volume *, Number *, 2014
presentation of ISCs.5 From an aesthetic perspective, particularly when implants are placed in the anterior region of the maxilla, the contour of the gingival margin of teeth and ISCs, the crown length, and the position in relation to adjacent teeth are significant factors for treatment success.6,7 In a 5-year multicenter study, Henry and colleagues8 reported an implant success rate of approximately 96% for single-tooth replacements in the anterior maxilla. However, they also reported an aesthetic failure rate of approximately 9% for implant placements in this area. This underscores the critical importance of aesthetics as a determinant of implant success and patient satisfaction.9 Many studies have concentrated on the osseointegration of titanium implants, bone loss after placement of restoration, and the number of implant and ISC losses over time.10–12 More recently, biological complications, aesthetics, and positional changes in relation to neighboring teeth have been included in reports of implant restorations.5,13–17 Most studies, however, mainly cover consecutively treated patients of different ages restored with implants due to underlying diagnoses such as trauma, periodontitis, and root fracture. These cases are not fully comparable with those of patients treated with implants due to congenitally missing teeth with sound bone and tissues in the area. There are few follow-up studies of implants placed in relatively young patients with congenitally missing teeth in the anterior region of the maxilla, so it is important to evaluate the long-term survival rate of these ISCs and to assess them in terms of aesthetics, soft tissue adaptation, and patient satisfaction. This retrospective study aimed to evaluate the 5-year survival of implants and ISCs and to assess their functional and aesthetic outcomes from the professional and patient perspectives. MATERIALS AND METHODS The Regional Ethical Review Board in Uppsala, Sweden, which follows the guidelines of the Declaration of Helsinki, approved the study protocol. Subject Sample Subjects for the study were recruited from the pool of patients treated with single ISCs due to diagnosis of congenitally missing lateral upper incisors at the Department of Prosthetic Dentistry in Karlstad, Sweden, between 2001 and 2004.
The inclusion criteria were as follows: (1) patients younger than 38 years at implant placement with unilateral or bilateral congenitally missing upper lateral incisors and (2) patients’ agreement to participate. A total of 46 patients with congenitally missing upper lateral incisors were treated with ISCs from 2001 to 2004; of these, 36 patients with 54 ISCs were examined clinically at the follow-up. None of the included subjects had periodontal disease, and all subjects had undergone orthodontic treatment with space opening prior to implant installation. The reasons for dropout were no contact in four cases, while six patients declined to participate (one patient completed the questionnaire but declined clinical examination). All implants were installed via flap surgery using mucoperiosteal flap according to either a one-stage (n = 27) or two-stage (n = 27) procedure by experienced oral surgeons. In one case, it was necessary to perform bone augmentation due to a buccal fenestration defect at the mid part of the implant. Only 15-mm (n = 45) or 13-mm (n = 9) Brånemark system® MKIII implants (Nobel Biocare AB, Göteborg, Sweden) (45 narrow-platform implants, diameter 3.3 mm, and nine regular-platform implants, diameter 3.75 mm) were used. The abutments were custom made in 44 cases (36 zirconia and eight titanium) and in 10 cases were prefabricated CeraOne abutments. The ISCs were all cement retained and comprised 53 all-ceramic crowns and one metal ceramic crown, all placed by experienced prosthodontists. Clinical Follow-Up Examination The patients were clinically examined by one of the authors according to a modification of the specific protocol of Chang.18 This protocol included assessments of ISCs with regard to aesthetics as well as the adaptation of surrounding soft tissue. ISC quality was assessed according to the California Dental Association (CDA)19 quality assessment evaluation index, which covers surface and color, anatomic shape, and marginal integrity. The clinical quality was rated either satisfactory or unacceptable with two possible subratings in each category. The satisfactory category comprises the subratings Romeo (R), which indicates “excellent,” and Sierra (S), which indicates “acceptable.” The unacceptable category comprises the subratings Tango (T), which indicates “should be replaced or repaired,” and Victor (V), which indicates
Implants in Agenesis of Maxillary Laterals
“must be replaced or repaired.” The lowest rating in any of the subcategories defines the final CDA score. All CDA registrations were made by one prosthodontist and one orthodontist acting independently of each other. Before the study, the examiners had been calibrated, and an interrater absolute agreement of 95% was achieved. When the study ratings differed between the two examiners, agreement was achieved through a complementary joint examination.
3
Papilla Height Index scores 0 = No papilla is present. 1 = Less than half the height of the papilla (HP) is present. 2 = Half or more of the height of the papilla is present. 3 = The papilla fill up the entire proximal space and are in good harmony with the adjacent papillae.
Figure 2 The papilla index according to Jemt’s description.20
Photographic Procedure and Assessments Intraoral photographs were taken to permit papilla index assessment. An Olympus E-620 digital camera (Olympus Corporation, Tokyo, Japan) with a ring flash and adjustable tripod was used according to a standard procedure. For imaging, all patients were positioned on an operator’s chair at the same height and distance from the camera and against a solid background. Enface and intraoral images of the ISCs were acquired from a preselected distance (indicated by adhesive strips on the floor) (Figure 1). Papilla height and embrasure fill in approximal spaces were evaluated according to Jemt’s papilla index20 (Figure 2). Radiographic Evaluations For the radiographic examinations, routine intraoral periapical radiographs were used. Radiographs were acquired after crown placement (baseline; n = 43), after approximately 1 year (n = 37), and at the 5-year examination (n = 41). Bone level was independently assessed by a credentialed oral radiologist. The radiographs were
studied for signs of disintegration and other pathology related to the implants. Marginal bone levels around the implants were measured mesially and distally. All measurements were made to the nearest 0.1 mm using a lens with ×7 magnification. Patient Questionnaires To evaluate the patient perspective on the long-term aesthetic outcome of the restoration, a modified Swedish version of the questionnaire used by Chang18 was presented to the patients in conjunction with the clinical follow-up visit. The questionnaire contains a total of nine questions, eight concerning the form, color, and appearance of the restorations, where satisfaction/ importance was to be rated from 1 (not at all) to 5 (completely/very). The last question dealt with the possible desire to have the crown replaced (yes/no), followed by an open-ended opportunity to comment. Data Analysis Survival, bone-level changes, CDA evaluation, papilla height, and patient satisfaction scores were described and cross tabulated in bivariate comparisons. A sum score of satisfaction (range 5–25) was computed based on the five questionnaire items concerning different aspects of satisfaction. For group comparisons, Fisher’s exact test was performed. A logistic regression analysis was performed with patient desire for crown replacement as the dependent variable and selected potential discriminatory variables as independents. Descriptive and analytical statistics were calculated using SPSS 17.0 (SPSS Inc., Chicago, IL, USA). RESULTS
Figure 1 Patient with multiple agenesis and a peg-shaped left lateral with implant-supported crown (ISC) replacing the right lateral.
The examined sample consisted of 17 men and 19 women who had their implants inserted at a fairly young age (Table 1). The follow-up time was 4 to 9 years (Table 1).
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Clinical Implant Dentistry and Related Research, Volume *, Number *, 2014
TABLE 1 Sample Characteristics for the Clinical Follow-Up Age at Implant Placement (Years)
Gender
Male Female Total
Length of Follow-Up Period (Years)
n
Mean
SD
Mean
SD
17 19 36
20.8 20.3 20.5
5.8 6.7 6.2
6.7 6.9 6.8
1.4 1.2 1.3
Age at implant placement varied between 15.9 and 37.4 years. Follow-up time ranged from 4 to 9 years. SD, standard deviation.
The survival of implants was 100%. Mean bone level in relation to the implant/abutment junction (IAJ) changed slightly with time, resulting in a mean bone loss of 0.3 mm between the three radiographic examinations (baseline to 1-year and 1-year to 5-year follow-up; Table 2). No difference was observed between men and women. At baseline, 72% of the implants presented a bone level within 0.6 mm of the IAJ. Only four implants (9%) had a bone level 31.8 mm from the IAJ. At the 5-year follow-up, 32% of the implants still had a bone level within 0.6 mm of the IAJ, while seven implants (17%) presented a bone level 31.8 mm from the IAJ. All ISCs were in place at follow-up, though one crown presented a porcelain fracture. The CDA evaluation of the surface and color, anatomic shape, and marginal integrity of the crowns revealed acceptable results (i.e., R or S) for all crowns (Table 3). For 38 of the crowns (70%), all dimensions were rated R. No crowns were rated unacceptable, but closer examination of the S (acceptable but not optimal) ratings revealed that a slight mismatch in color and shape was the main reason for not reaching R status (Table 3). The papilla height and fill in approximal spaces according to the papilla index was optimal (score 3) for 30 (56%) of the implants, while 15 (28%) scored 2 and
7 (13%) and two (4%) scored 1 or 0, indicating unacceptable papilla contour (less than half of the optimal height) at the 5-year follow-up. The mean sum score for patient satisfaction based on five items was 21.08 (SD 3.0), being similar for men (n = 17; mean 21.24, SD 2.7) and women (n = 20; mean 20.95, SD 3.3). Single-item means were 4.4 for crown form and overall appearance and 4.1 for crown color, appearance when smiling, and harmony with adjacent teeth (see Table 4 for frequency distributions per item). According to the overall satisfaction item, 21 of the 37 patients completing the questionnaire were completely satisfied with the treatment (Table 4). Twelve patients reported a desire for crown replacement (i.e., form, two; color, three; visible abutment, three; harmony with adjacent teeth, two; fracture, one; and unspecified, one). Comparing the 12 patients desiring crown replacement with the rest of the patients revealed that 64% of those requesting a remake were in the age span of 20 to 25 compared with 42% among the rest of the patients. There were more nonoptimal CDA assessments (S) for surface and color in the group desiring a remake (25% vs 8%; ns), while the proportions with nonoptimal CDA assessments of anatomic shape were similar between groups (8%). Papilla index values 22 were more
TABLE 2 Marginal Bone Level (mm) in Relation to the IAJ and Bone Loss from Baseline to 1- and 5-Year Follow-Up Bone Level in Relation to IAJ (mm)
Baseline 1 year 5 years
Bone Loss Between Examinations (mm)
n
Mean
SD
43 37 41
0.5 0.8 1.1
0.8 0.7 0.8
Number of implants analyzed (n). IAJ, implant/abutment junction; SD, standard deviation.
Baseline to 1 year 1 year to 5 years Baseline to 5 years
n
Mean
SD
34 30 36
0.3 0.3 0.6
0.5 0.5 0.7
Implants in Agenesis of Maxillary Laterals
5
TABLE 3 Percentage Distribution of Implant-Supported Crowns with Respect to Evaluation in Accordance with the CDA System at Follow-Up Satisfactory
Surface and color Anatomic shape Marginal integrity Final score
Not Acceptable
R
S
Total
T
V
Total
87 93 91 70
13 7 9 30
100 100 100 100
0 0 0 0
0 0 0 0
0 0 0 0
CDA, California Dental Association; R, Romeo; S, Sierra; T, Tango; V, Victor.
frequent in the group of patients desiring crown replacement (58% vs 37.5%; ns). When the papilla index, CDA assessment of surface and color, and age were all taken into account, the papilla index was, although nonsignificant, the strongest variable possibly determining the desire for crown replacement (Table 5). DISCUSSION The present study confirms earlier findings concerning good implant and ISC survival from a 5-year or longer perspective.13,14,21 However, the patient questionnaire results indicated that despite acceptable CDA ratings for ISC color and form, 12 patients were interested in having their crowns replaced, for a patient dissatisfaction rate of 32%. The reason for considering a replacement of the existing crown differed between patients,
although patients with lower papilla index scores tended to be more dissatisfied. The small sample did not allow subgroup analyses, but the desire for crown replacement was proportionally distributed between patients with different implant diameters and abutment materials. In the present study, the patients were not specifically asked to judge the soft tissue. However, all patients citing visible abutments as the reason for desiring crown replacement were provided with ceramic abutments. The high success rate of ISCs has been demonstrated in previous studies.22 From an aesthetic perspective, particularly when implants are installed in the anterior region of the maxilla, the soft tissue topography around the ISC is an important factor determining treatment success.17,23 It has been postulated that mucosa thickness and the level of bone support adjacent
TABLE 4 Patient Assessments of Satisfaction/Importance of Esthetic Aspects of the Implant-Supported Crown (Valid Data n = 37) Not at All Satisfied = 1 (Count)
Crown form* Color of the crown* Appearance when smiling* Harmony with adjacent natural teeth* Overall appearance* Overall satisfaction
Abutment visibility Optimum esthetics *Item included in sum score.
2 (Count)
3 (Count)
4 (Count)
Completely Satisfied = 5 (Count)
1 1 1 1
5 5 7 5 2 2
13 20 16 20 16 14
19 11 13 11 18 21
Not at All Important = 1 (count)
2 (count)
3 (count)
4 (count)
Very Important = 5 (count)
4 1
2 2
2 9
12 12
17 13
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Clinical Implant Dentistry and Related Research, Volume *, Number *, 2014
TABLE 5 Logistic Regression Analysis with Desire for Remake of the Crown as Dependent Variable and Potential Discriminatory Variables as Independents Independent Variable
Age group 0/1 (20–25 = 1; older = 0) Papilla index 0/1 (22 = 1; 3 = 0) CDA, surface, and color (Sierra = 1, Romeo = 0)
Odds Ratio
95% CI
p Value
3.08 4.33 1.66
0.57–16.74 0.83–22.60 0.15–18.87
.193 .082 .684
Method: ENTER; Included in analyses n = 34 patients; Nagelkerke R2, 187. CDA, California Dental Association; CI, confidence interval.
to implant-supported reconstructions determine the height of the supracrestal soft tissue portion around dental implants.24 In addition, the facial–lingual width of the papilla base, the contact point distance between the crowns, and the bone level at the tooth, as well as implant/crown dimensions and design, have been suggested as factors potentially affecting the degree of embrasure fill.5 The papilla index score in the current study was suboptimal in 44% of ISCs at 5-year followup. In cases of congenitally missing teeth, the facial– lingual width of the papilla base and the bone volume at the site of the agenesis are often compromised and could therefore be the reason for the poorer embrasure fill in these cases. In the present study, most implants used were of the narrow platform type, indicating reduced available bone volume. The CDA rating of all ISCs examined in the current study was high, and for 70% of the crowns, all dimensions were rated R. One probable explanation for the S rating of color and surface at the 5-year follow-up could be time-dependent natural changes of the adjacent teeth. Agenesis of maxillary lateral incisors has been found to be a significant predictor of tooth size as well. Patients with congenitally missing lateral incisors have smaller teeth, except for maxillary first molars, than do control subjects.4 This information could be of importance for clinicians choosing crown width in such cases, as crown width must be in harmony with the neighboring teeth and overall dentition. This study has some clear limitations. The study group was small and did not allow for deeper statistical evaluation of the variables of interest. The lack of pretreatment plaster models and standardized photographs at baseline also limited the evaluation of changes in ISC vertical positioning in relation to adjacent teeth. With the continuous eruption of the adjacent teeth with infraocclusal positioning of the implant restoration as a consequence might explain aesthetic dissatisfaction and
should be considered when planning future prospective research with long-term follow-ups of implants and ISCs from an aesthetic perspective. Further, in the present study, the ISC was evaluated clinically using the CDA index, and the peri-implant soft tissue was only evaluated using the papilla index according to Jemt.20 Thus, differences in crown length and soft tissue discrepancies in color, texture, and contour were not evaluated. An objective score for the assessment of the peri-implant soft tissue has been invented and tested by Fürhauser and colleagues, the so called pink esthetic score (PES). PES uses a reference tooth (i.e., the corresponding tooth and seven variables for the assessment of the peri-implant soft tissue: mesial papilla, distal papilla, soft tissue level, soft tissue contour, alveolar process deficiency, soft tissue color, and texture).25 In the present study, 18 of the patients had bilateral agenesia of the laterals, and six had a contralateral tooth with an atypical shape. Hence, this index was not easily adapted for most of the ISCs and therefore not used. A more thorough evaluation of the ISC using a modified PES and WES may have provided a better description of the aesthetic outcome. CONCLUSIONS In conclusion, from a professional perspective, the 5-year follow-up outcome of implant-supported singlecrown restorations in cases of maxillary lateral agenesis was very good. However, from a patient perspective, although most were satisfied with the aesthetics and function, a third of patients desired crown replacement, and soft tissue adaptation was indicated to be an important factor affecting satisfaction. Further and prospective clinical studies, taking the patient perspective into account, are needed. ACKNOWLEDGMENTS The authors would like to thank Dr. Per Häger, Department of Prosthetic Dentistry in Karlstad, Sweden, and
Implants in Agenesis of Maxillary Laterals
associate professor Björn Svensson, Department of Oral Radiology in Örebro, Sweden, for their invaluable assistance in this study. The authors declare that they have no conflict of interest.
13.
14.
REFERENCES 1. Kavadia S, Papadiochou S, Papadiochos I, Zafiriadis L. Agenesis of maxillary lateral incisors: a global overview of the clinical problem. Orthodontics (Chic) 2011; 12:296– 317. 2. Fujita Y, Hidaka A, Nishida I, Morikawa K, Hashiguchi D, Maki K. Developmental anomalies of permanent lateral incisors in young patients. J Clin Pediatr Dent 2009; 33:211–215. 3. Aasheim B, Ogaard B. Hypodontia in 9-year-old Norwegians related to need of orthodontic treatment. Scand J Dent Res 1993; 101:257–260. 4. Mirabella AD, Kokich VG, Rosa M. Analysis of crown widths in subjects with congenitally missing maxillary lateral incisors. Eur J Orthod 2012; 34:783–787. 5. Chang M, Wennstrom JL. Soft tissue topography and dimensions lateral to single implant-supported restorations: a cross-sectional study. Clin Oral Implants Res 2013; 24:556– 562. 6. Chang M, Wennstrom JL. Longitudinal changes in tooth/ single-implant relationship and bone topography: an 8-year retrospective analysis. Clin Implant Dent Relat Res 2012; 14:388–394. 7. Belser UC, Grütter L, Vailati F, Bornstein MM, Weber HP, Buser D. Outcome evaluation of early placed maxillary anterior single-tooth implants using objective esthetic criteria: a cross-sectional, retrospective study in 45 patients with a 2to 4-year follow-up using pink and white esthetic scores. J Periodontol 2009; 80:140–151. 8. Henry PJ, Laney WR, Jemt T, et al. Osseointegrated implants for single-tooth replacement: a prospective 5-year multicenter study. Int J Oral Maxillofac Implants 1996; 11:450– 455. 9. Al-Sabbagh M. Implants in the esthetic zone. Dent Clin North Am 2006; 50:391–407. vi. 10. Andersson B, Odman P, Lindvall AM, Branemark PI. Cemented single crowns on osseointegrated implants after 5 years: results from a prospective study on CeraOne. Int J Prosthodont 1998; 11:212–218. 11. Jemt T. Cemented CeraOne and porcelain fused to TiAdapt abutment single-implant crown restorations: a 10-year comparative follow-up study. Clin Implant Dent Relat Res 2009; 11:303–310. 12. Degidi M, Nardi D, Piattelli A. Immediate versus one-stage restoration of small-diameter implants for a single missing
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maxillary lateral incisor: a 3-year randomized clinical trial. J Periodontol 2009; 80:1393–1398. Gotfredsen K. A 10-year prospective study of single tooth implants placed in the anterior maxilla. Clin Implant Dent Relat Res 2012; 14:80–87. Bergenblock S, Andersson B, Furst B, Jemt T. Long-term follow-up of CeraOne single-implant restorations: an 18-year follow-up study based on a prospective patient cohort. Clin Implant Dent Relat Res 2012; 14:471–479. Buser D, Chappuis V, Bornstein MM, Wittneben JG, Frei M, Belser UC. Long-term stability of contour augmentation with early implant placement following single tooth extraction in the esthetic zone: a prospective, cross-sectional study in 41 patients with a 5- to 9-year follow-up. J Periodontol 2013; 84:1517–1527. Si MS, Zhuang LF, Huang X, Gu YX, Chou CH, Lai HC. Papillae alterations around single-implant restorations in the anterior maxillae: thick versus thin mucosa. Int J Oral Sci 2012; 4:94–100. Cosyn J, Eghbali A, Hanselaer L, et al. Four modalities of single implant treatment in the anterior maxilla: a clinical, radiographic, and aesthetic evaluation. Clin Implant Dent Relat Res 2013; 15:517–530. Chang M. The peri-implant tissues from an esthetic perspective. Thesis. Gothenburg, Sweden: Sahlgrenska Academy, University of Gothenburg, 2009. California Dental Association. Quality evaluation for dental care: guidelines for assessment of clinical quality and professional performance. Los Angeles, CA, USA: California Dental Association, 1977. Jemt T. Regeneration of gingival papillae after singleimplant treatment. Int J Periodontics Restorative Dent 1997; 17:326–333. Jemt T. Single implants in the anterior maxilla after 15 years of follow-up: comparison with central implants in the edentulous maxilla. Int J Prosthodont 2008; 21:400–408. Jung RE, Pjetursson BE, Glauser R, Zembic A, Zwahlen M, Lang NP. A systematic review of the 5-year survival and complication rates of implant-supported single crowns. Clin Oral Implants Res 2008; 19:119–130. Chang M, Odman PA, Wennstrom JL, Andersson B. Esthetic outcome of implant-supported single-tooth replacements assessed by the patient and by prosthodontists. Int J Prosthodont 1999; 12:335–341. Bengazi F, Wennstrom JL, Lekholm U. Recession of the soft tissue margin at oral implants. A 2-year longitudinal prospective study. Clin Oral Implants Res 1996; 7:303–310. Fürhauser R, Florescu D, Benesch T, Haas R, Mailath G, Watzek G. Evaluation of soft tissue around single-tooth implant crowns: the pink esthetic score. Clin Oral Implants Res 2005; 16:639–644.
ABSTRACT Background: Knowledge of the long-term survival of single implants in cases of congenitally missing lateral incisors in the maxilla is limited. Purpose: This retrospective study aimed to evaluate the 5-year survival of implants and implant-supported crowns (ISCs) and to assess the functional and aesthetic outcomes from the professional and patient perspectives. Materials and Methods: From a total of 46 patients with congenitally missing upper lateral incisors, 36 patients treated with 54 Brånemark® (Nobel Biocare AB, Göteborg, Sweden) implants and ISCs participated in the study. A clinical examination, California Dental Association (CDA) evaluation, and patient questionnaire were used to rate and compare the objective and subjective evaluations of the ISCs. Results: The survival of implants and ISCs was 100%. The CDA ratings were satisfactory for all ISCs, with 70% being rated excellent. The patient rating was also high for the overall satisfaction item, with 21 being completely satisfied and 14 fairly satisfied. However, 12 patients wished for the replacement of their ISCs. Logistic regression analysis indicated that a less optimal embrasure fill was the most discriminating factor though not statistically significant (p = .082). Conclusions: One-third of the patients wished for the replacement of their ISCs. Soft tissue adaptation seems to be an important factor for overall satisfaction. KEY WORDS: agenesis, dental implants, dental papillae, follow-up, patient satisfaction
INTRODUCTION
absence is more common bilaterally than unilaterally. Sex differences in prevalence have usually been found to be small with slightly more women than men affected.2,3 Genetic and environmental factors have been implicated in congenitally missing teeth, and recent studies have demonstrated the predominant role of genetics in the aetiology of this condition.4 Replacing the maxillary lateral incisors with implant-supported single-crown restorations is today a widely recognized method. As well as not harming the sound parts of the natural dentition, such restorations have the following advantages: (1) alveolar bone preservation; (2) enhancement of occlusal function; (3) enhanced appearance; (4) oral hygiene facilitation; and (5) long-term survival.1 The topography of the peri-implant mucosa in terms of the position of the soft tissue margin on the facial aspect of the implant-supported crown (ISC) and the degree of papilla fill in the embrasure spaces lateral to the crown are important factors affecting the aesthetic
Agenesis is the congenital lack of tooth buds. Agenesis of maxillary lateral incisors occurs in approximately 1% to 3% of the population in north-western Europe and is the most common missing tooth after the second premolar, excluding the third molars.1 This congenital
*Senior consultant, Specialist Clinic of Orthodontics, Public Dental Health Service, Karlstad, Sweden; †senior consultant, Department of Prosthetic Dentistry, Postgraduate Dental Education Center and School of Health and Medical Sciences, Örebro University, Örebro, Sweden; ‡associate professor, senior consultant, Dental Research Department, Public Dental Health Service, Örebro County Council and School of Health and Medical Sciences, Örebro University, Örebro, Sweden; §senior consultant, Department of Orthodontics, Postgraduate Dental Education Center, Örebro, Sweden Corresponding Author: Dr. Farhan Bazargani, Department of Orthodontics, Postgraduate Dental Education Center, P.O. Box 1126, SE- 701 11 Örebro, Sweden; e-mail: [email protected] © 2014 Wiley Periodicals, Inc. DOI 10.1111/cid.12233
1
2
Clinical Implant Dentistry and Related Research, Volume *, Number *, 2014
presentation of ISCs.5 From an aesthetic perspective, particularly when implants are placed in the anterior region of the maxilla, the contour of the gingival margin of teeth and ISCs, the crown length, and the position in relation to adjacent teeth are significant factors for treatment success.6,7 In a 5-year multicenter study, Henry and colleagues8 reported an implant success rate of approximately 96% for single-tooth replacements in the anterior maxilla. However, they also reported an aesthetic failure rate of approximately 9% for implant placements in this area. This underscores the critical importance of aesthetics as a determinant of implant success and patient satisfaction.9 Many studies have concentrated on the osseointegration of titanium implants, bone loss after placement of restoration, and the number of implant and ISC losses over time.10–12 More recently, biological complications, aesthetics, and positional changes in relation to neighboring teeth have been included in reports of implant restorations.5,13–17 Most studies, however, mainly cover consecutively treated patients of different ages restored with implants due to underlying diagnoses such as trauma, periodontitis, and root fracture. These cases are not fully comparable with those of patients treated with implants due to congenitally missing teeth with sound bone and tissues in the area. There are few follow-up studies of implants placed in relatively young patients with congenitally missing teeth in the anterior region of the maxilla, so it is important to evaluate the long-term survival rate of these ISCs and to assess them in terms of aesthetics, soft tissue adaptation, and patient satisfaction. This retrospective study aimed to evaluate the 5-year survival of implants and ISCs and to assess their functional and aesthetic outcomes from the professional and patient perspectives. MATERIALS AND METHODS The Regional Ethical Review Board in Uppsala, Sweden, which follows the guidelines of the Declaration of Helsinki, approved the study protocol. Subject Sample Subjects for the study were recruited from the pool of patients treated with single ISCs due to diagnosis of congenitally missing lateral upper incisors at the Department of Prosthetic Dentistry in Karlstad, Sweden, between 2001 and 2004.
The inclusion criteria were as follows: (1) patients younger than 38 years at implant placement with unilateral or bilateral congenitally missing upper lateral incisors and (2) patients’ agreement to participate. A total of 46 patients with congenitally missing upper lateral incisors were treated with ISCs from 2001 to 2004; of these, 36 patients with 54 ISCs were examined clinically at the follow-up. None of the included subjects had periodontal disease, and all subjects had undergone orthodontic treatment with space opening prior to implant installation. The reasons for dropout were no contact in four cases, while six patients declined to participate (one patient completed the questionnaire but declined clinical examination). All implants were installed via flap surgery using mucoperiosteal flap according to either a one-stage (n = 27) or two-stage (n = 27) procedure by experienced oral surgeons. In one case, it was necessary to perform bone augmentation due to a buccal fenestration defect at the mid part of the implant. Only 15-mm (n = 45) or 13-mm (n = 9) Brånemark system® MKIII implants (Nobel Biocare AB, Göteborg, Sweden) (45 narrow-platform implants, diameter 3.3 mm, and nine regular-platform implants, diameter 3.75 mm) were used. The abutments were custom made in 44 cases (36 zirconia and eight titanium) and in 10 cases were prefabricated CeraOne abutments. The ISCs were all cement retained and comprised 53 all-ceramic crowns and one metal ceramic crown, all placed by experienced prosthodontists. Clinical Follow-Up Examination The patients were clinically examined by one of the authors according to a modification of the specific protocol of Chang.18 This protocol included assessments of ISCs with regard to aesthetics as well as the adaptation of surrounding soft tissue. ISC quality was assessed according to the California Dental Association (CDA)19 quality assessment evaluation index, which covers surface and color, anatomic shape, and marginal integrity. The clinical quality was rated either satisfactory or unacceptable with two possible subratings in each category. The satisfactory category comprises the subratings Romeo (R), which indicates “excellent,” and Sierra (S), which indicates “acceptable.” The unacceptable category comprises the subratings Tango (T), which indicates “should be replaced or repaired,” and Victor (V), which indicates
Implants in Agenesis of Maxillary Laterals
“must be replaced or repaired.” The lowest rating in any of the subcategories defines the final CDA score. All CDA registrations were made by one prosthodontist and one orthodontist acting independently of each other. Before the study, the examiners had been calibrated, and an interrater absolute agreement of 95% was achieved. When the study ratings differed between the two examiners, agreement was achieved through a complementary joint examination.
3
Papilla Height Index scores 0 = No papilla is present. 1 = Less than half the height of the papilla (HP) is present. 2 = Half or more of the height of the papilla is present. 3 = The papilla fill up the entire proximal space and are in good harmony with the adjacent papillae.
Figure 2 The papilla index according to Jemt’s description.20
Photographic Procedure and Assessments Intraoral photographs were taken to permit papilla index assessment. An Olympus E-620 digital camera (Olympus Corporation, Tokyo, Japan) with a ring flash and adjustable tripod was used according to a standard procedure. For imaging, all patients were positioned on an operator’s chair at the same height and distance from the camera and against a solid background. Enface and intraoral images of the ISCs were acquired from a preselected distance (indicated by adhesive strips on the floor) (Figure 1). Papilla height and embrasure fill in approximal spaces were evaluated according to Jemt’s papilla index20 (Figure 2). Radiographic Evaluations For the radiographic examinations, routine intraoral periapical radiographs were used. Radiographs were acquired after crown placement (baseline; n = 43), after approximately 1 year (n = 37), and at the 5-year examination (n = 41). Bone level was independently assessed by a credentialed oral radiologist. The radiographs were
studied for signs of disintegration and other pathology related to the implants. Marginal bone levels around the implants were measured mesially and distally. All measurements were made to the nearest 0.1 mm using a lens with ×7 magnification. Patient Questionnaires To evaluate the patient perspective on the long-term aesthetic outcome of the restoration, a modified Swedish version of the questionnaire used by Chang18 was presented to the patients in conjunction with the clinical follow-up visit. The questionnaire contains a total of nine questions, eight concerning the form, color, and appearance of the restorations, where satisfaction/ importance was to be rated from 1 (not at all) to 5 (completely/very). The last question dealt with the possible desire to have the crown replaced (yes/no), followed by an open-ended opportunity to comment. Data Analysis Survival, bone-level changes, CDA evaluation, papilla height, and patient satisfaction scores were described and cross tabulated in bivariate comparisons. A sum score of satisfaction (range 5–25) was computed based on the five questionnaire items concerning different aspects of satisfaction. For group comparisons, Fisher’s exact test was performed. A logistic regression analysis was performed with patient desire for crown replacement as the dependent variable and selected potential discriminatory variables as independents. Descriptive and analytical statistics were calculated using SPSS 17.0 (SPSS Inc., Chicago, IL, USA). RESULTS
Figure 1 Patient with multiple agenesis and a peg-shaped left lateral with implant-supported crown (ISC) replacing the right lateral.
The examined sample consisted of 17 men and 19 women who had their implants inserted at a fairly young age (Table 1). The follow-up time was 4 to 9 years (Table 1).
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Clinical Implant Dentistry and Related Research, Volume *, Number *, 2014
TABLE 1 Sample Characteristics for the Clinical Follow-Up Age at Implant Placement (Years)
Gender
Male Female Total
Length of Follow-Up Period (Years)
n
Mean
SD
Mean
SD
17 19 36
20.8 20.3 20.5
5.8 6.7 6.2
6.7 6.9 6.8
1.4 1.2 1.3
Age at implant placement varied between 15.9 and 37.4 years. Follow-up time ranged from 4 to 9 years. SD, standard deviation.
The survival of implants was 100%. Mean bone level in relation to the implant/abutment junction (IAJ) changed slightly with time, resulting in a mean bone loss of 0.3 mm between the three radiographic examinations (baseline to 1-year and 1-year to 5-year follow-up; Table 2). No difference was observed between men and women. At baseline, 72% of the implants presented a bone level within 0.6 mm of the IAJ. Only four implants (9%) had a bone level 31.8 mm from the IAJ. At the 5-year follow-up, 32% of the implants still had a bone level within 0.6 mm of the IAJ, while seven implants (17%) presented a bone level 31.8 mm from the IAJ. All ISCs were in place at follow-up, though one crown presented a porcelain fracture. The CDA evaluation of the surface and color, anatomic shape, and marginal integrity of the crowns revealed acceptable results (i.e., R or S) for all crowns (Table 3). For 38 of the crowns (70%), all dimensions were rated R. No crowns were rated unacceptable, but closer examination of the S (acceptable but not optimal) ratings revealed that a slight mismatch in color and shape was the main reason for not reaching R status (Table 3). The papilla height and fill in approximal spaces according to the papilla index was optimal (score 3) for 30 (56%) of the implants, while 15 (28%) scored 2 and
7 (13%) and two (4%) scored 1 or 0, indicating unacceptable papilla contour (less than half of the optimal height) at the 5-year follow-up. The mean sum score for patient satisfaction based on five items was 21.08 (SD 3.0), being similar for men (n = 17; mean 21.24, SD 2.7) and women (n = 20; mean 20.95, SD 3.3). Single-item means were 4.4 for crown form and overall appearance and 4.1 for crown color, appearance when smiling, and harmony with adjacent teeth (see Table 4 for frequency distributions per item). According to the overall satisfaction item, 21 of the 37 patients completing the questionnaire were completely satisfied with the treatment (Table 4). Twelve patients reported a desire for crown replacement (i.e., form, two; color, three; visible abutment, three; harmony with adjacent teeth, two; fracture, one; and unspecified, one). Comparing the 12 patients desiring crown replacement with the rest of the patients revealed that 64% of those requesting a remake were in the age span of 20 to 25 compared with 42% among the rest of the patients. There were more nonoptimal CDA assessments (S) for surface and color in the group desiring a remake (25% vs 8%; ns), while the proportions with nonoptimal CDA assessments of anatomic shape were similar between groups (8%). Papilla index values 22 were more
TABLE 2 Marginal Bone Level (mm) in Relation to the IAJ and Bone Loss from Baseline to 1- and 5-Year Follow-Up Bone Level in Relation to IAJ (mm)
Baseline 1 year 5 years
Bone Loss Between Examinations (mm)
n
Mean
SD
43 37 41
0.5 0.8 1.1
0.8 0.7 0.8
Number of implants analyzed (n). IAJ, implant/abutment junction; SD, standard deviation.
Baseline to 1 year 1 year to 5 years Baseline to 5 years
n
Mean
SD
34 30 36
0.3 0.3 0.6
0.5 0.5 0.7
Implants in Agenesis of Maxillary Laterals
5
TABLE 3 Percentage Distribution of Implant-Supported Crowns with Respect to Evaluation in Accordance with the CDA System at Follow-Up Satisfactory
Surface and color Anatomic shape Marginal integrity Final score
Not Acceptable
R
S
Total
T
V
Total
87 93 91 70
13 7 9 30
100 100 100 100
0 0 0 0
0 0 0 0
0 0 0 0
CDA, California Dental Association; R, Romeo; S, Sierra; T, Tango; V, Victor.
frequent in the group of patients desiring crown replacement (58% vs 37.5%; ns). When the papilla index, CDA assessment of surface and color, and age were all taken into account, the papilla index was, although nonsignificant, the strongest variable possibly determining the desire for crown replacement (Table 5). DISCUSSION The present study confirms earlier findings concerning good implant and ISC survival from a 5-year or longer perspective.13,14,21 However, the patient questionnaire results indicated that despite acceptable CDA ratings for ISC color and form, 12 patients were interested in having their crowns replaced, for a patient dissatisfaction rate of 32%. The reason for considering a replacement of the existing crown differed between patients,
although patients with lower papilla index scores tended to be more dissatisfied. The small sample did not allow subgroup analyses, but the desire for crown replacement was proportionally distributed between patients with different implant diameters and abutment materials. In the present study, the patients were not specifically asked to judge the soft tissue. However, all patients citing visible abutments as the reason for desiring crown replacement were provided with ceramic abutments. The high success rate of ISCs has been demonstrated in previous studies.22 From an aesthetic perspective, particularly when implants are installed in the anterior region of the maxilla, the soft tissue topography around the ISC is an important factor determining treatment success.17,23 It has been postulated that mucosa thickness and the level of bone support adjacent
TABLE 4 Patient Assessments of Satisfaction/Importance of Esthetic Aspects of the Implant-Supported Crown (Valid Data n = 37) Not at All Satisfied = 1 (Count)
Crown form* Color of the crown* Appearance when smiling* Harmony with adjacent natural teeth* Overall appearance* Overall satisfaction
Abutment visibility Optimum esthetics *Item included in sum score.
2 (Count)
3 (Count)
4 (Count)
Completely Satisfied = 5 (Count)
1 1 1 1
5 5 7 5 2 2
13 20 16 20 16 14
19 11 13 11 18 21
Not at All Important = 1 (count)
2 (count)
3 (count)
4 (count)
Very Important = 5 (count)
4 1
2 2
2 9
12 12
17 13
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Clinical Implant Dentistry and Related Research, Volume *, Number *, 2014
TABLE 5 Logistic Regression Analysis with Desire for Remake of the Crown as Dependent Variable and Potential Discriminatory Variables as Independents Independent Variable
Age group 0/1 (20–25 = 1; older = 0) Papilla index 0/1 (22 = 1; 3 = 0) CDA, surface, and color (Sierra = 1, Romeo = 0)
Odds Ratio
95% CI
p Value
3.08 4.33 1.66
0.57–16.74 0.83–22.60 0.15–18.87
.193 .082 .684
Method: ENTER; Included in analyses n = 34 patients; Nagelkerke R2, 187. CDA, California Dental Association; CI, confidence interval.
to implant-supported reconstructions determine the height of the supracrestal soft tissue portion around dental implants.24 In addition, the facial–lingual width of the papilla base, the contact point distance between the crowns, and the bone level at the tooth, as well as implant/crown dimensions and design, have been suggested as factors potentially affecting the degree of embrasure fill.5 The papilla index score in the current study was suboptimal in 44% of ISCs at 5-year followup. In cases of congenitally missing teeth, the facial– lingual width of the papilla base and the bone volume at the site of the agenesis are often compromised and could therefore be the reason for the poorer embrasure fill in these cases. In the present study, most implants used were of the narrow platform type, indicating reduced available bone volume. The CDA rating of all ISCs examined in the current study was high, and for 70% of the crowns, all dimensions were rated R. One probable explanation for the S rating of color and surface at the 5-year follow-up could be time-dependent natural changes of the adjacent teeth. Agenesis of maxillary lateral incisors has been found to be a significant predictor of tooth size as well. Patients with congenitally missing lateral incisors have smaller teeth, except for maxillary first molars, than do control subjects.4 This information could be of importance for clinicians choosing crown width in such cases, as crown width must be in harmony with the neighboring teeth and overall dentition. This study has some clear limitations. The study group was small and did not allow for deeper statistical evaluation of the variables of interest. The lack of pretreatment plaster models and standardized photographs at baseline also limited the evaluation of changes in ISC vertical positioning in relation to adjacent teeth. With the continuous eruption of the adjacent teeth with infraocclusal positioning of the implant restoration as a consequence might explain aesthetic dissatisfaction and
should be considered when planning future prospective research with long-term follow-ups of implants and ISCs from an aesthetic perspective. Further, in the present study, the ISC was evaluated clinically using the CDA index, and the peri-implant soft tissue was only evaluated using the papilla index according to Jemt.20 Thus, differences in crown length and soft tissue discrepancies in color, texture, and contour were not evaluated. An objective score for the assessment of the peri-implant soft tissue has been invented and tested by Fürhauser and colleagues, the so called pink esthetic score (PES). PES uses a reference tooth (i.e., the corresponding tooth and seven variables for the assessment of the peri-implant soft tissue: mesial papilla, distal papilla, soft tissue level, soft tissue contour, alveolar process deficiency, soft tissue color, and texture).25 In the present study, 18 of the patients had bilateral agenesia of the laterals, and six had a contralateral tooth with an atypical shape. Hence, this index was not easily adapted for most of the ISCs and therefore not used. A more thorough evaluation of the ISC using a modified PES and WES may have provided a better description of the aesthetic outcome. CONCLUSIONS In conclusion, from a professional perspective, the 5-year follow-up outcome of implant-supported singlecrown restorations in cases of maxillary lateral agenesis was very good. However, from a patient perspective, although most were satisfied with the aesthetics and function, a third of patients desired crown replacement, and soft tissue adaptation was indicated to be an important factor affecting satisfaction. Further and prospective clinical studies, taking the patient perspective into account, are needed. ACKNOWLEDGMENTS The authors would like to thank Dr. Per Häger, Department of Prosthetic Dentistry in Karlstad, Sweden, and
Implants in Agenesis of Maxillary Laterals
associate professor Björn Svensson, Department of Oral Radiology in Örebro, Sweden, for their invaluable assistance in this study. The authors declare that they have no conflict of interest.
13.
14.
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