Brian Stevenson Dipali Patel, David Ricketts and Alison Cord

The Orthodontic-Restorative Interface in Patients with Hypodontia: The Patient’s Journey Abstract: Congenitally absent teeth may pose aesthetic and functional problems for patients. Treatment is often complex and involves a multidisciplinary team. Using retrospective data, the patient’s pathway, when a combined orthodontic-restorative dentistry approach was used, will be summarized. It was found that the number of teeth missing ranged from 1 to 8 with a mean of 3.4 per patient. Combined treatment was found to take on average around 38 months, using over 20 appointments. Clinical Relevance: Hypodontia is a relatively common condition. It is important that practitioners and patients are aware of the length of time treatment can take. Dent Update 2013; 40: 354–360

Hypodontia is a common condition that affects around 4% of the British population.1 The treatment of hypodontia can often be complex and involves a multidisciplinary approach that includes numerous members of the dental team (paediatric dentists, orthodontists, restorative specialists, oral surgeons, general dental practitioners and dental therapists). In addition, the condition, and possibly the length and complexity of treatment, has been shown to reduce objective measures of quality of life in this patient group.2

Brian Stevenson, BDS, PhD, MFDS FHEA, Consultant/Hon Senior Clinical Lecturer in Restorative Dentistry, Dipali Patel, BDS, MFDS, Specialist Registrar in Orthodontics, David Ricketts, BDS, MSc, PhD, FDS FDS(Rest Dent), Professor of Cariology and Conservative Dentistry and Alison Cord, BDS, MMedSc FDS, MOrth FDS(Ortho), Consultant in Orthodontics, Dundee Dental Hospital, Park Place, Dundee, UK.

354 DentalUpdate

The most common teeth to be congenitally missing (after third molars) are, the second mandibular premolars, maxillary lateral incisors and maxillary second premolars.3 Congenitally missing teeth are often categorized into hypodontia (≤6 teeth), severe hypodontia (>6 teeth) and anodontia (no teeth). Overall, 48% of patients with hypodontia have a single missing tooth whilst 35% have 2 teeth missing.3 However, concerning maxillary lateral incisors, it is more common for patients to be missing both than a solitary one.3 One of the most common clinical scenarios that requires treatment is when at least one maxillary lateral incisor is congenitally absent. The aetiology of hypodontia is complex with genetic factors (autosomal dominant trait with variable expressivity and penetrance), homeobox gene mutations (PAX9, MSX1, AXIN2),4 systemic disturbances (rubella,5 radiation therapy) and localized disturbances all contributing. The condition is 1.37 times more common in females than in males and individuals of European descent are more commonly affected than Caucasian Americans, who in turn are more commonly

affected than African Americans.3 Treatment of individuals with hypodontia is often complicated by other dental factors (microdontia, spacing, dentoalveolar disproportion, altered eruption, infra-occlusion of deciduous teeth, tipping and over-eruption) and other conditions (Cleft Lip and Palate, Ectodermal Dysplasia, van der Woude syndrome, Down’s syndrome). Several of these problems are illustrated in Figure 1. Aesthetic and occlusal problems can often occur due to these dental factors. Treatment usually begins with an initial joint consultation to assess the patient, and then treatment can involve a solely restorative or solely orthodontic approach or, more commonly, combined orthodontic-restorative treatment. Combined treatment planning clinics usually involve at least one consultant restorative dentist and his/her specialist registrar (part-way through a five-year training programme), a consultant orthodontist and his/her orthodontic specialist registrar (part-way through a three-year training programme) and an orthodontist who has completed a specialist June 2013

© MA Healthcare Ltd. Downloaded from by on September 30, 2017. Use for licensed purposes only. No other uses without permission. All rights reserved.


training programme and has subsequently been appointed to a FTTA (Fixed Term Training Appointment) position that lasts for 2 years. The British Orthodontic Society (BOS) guidelines, on gaining informed consent for orthodontic treatment, recommend that patients should receive sufficient information about the proposed treatment, including a realistic estimate of the timescale.6 As part of the consent process, patients should be informed as to the duration of treatment, time period between the orthodontic and restorative phases of treatment and possible risks/ benefits of treatment. There is little evidence in the literature on duration of treatment for patients with hypodontia who require a


combined orthodontic-restorative dentistry approach to their management. It is essential during the consent process that the patient has a clear understanding of the restorative options that are available at the end of orthodontic treatment. For example, it would be wrong for a patient to undergo protracted orthodontic treatment to create space for a prosthetic replacement if the long-term maintenance and expected survival were not emphasized. This paper aims to outline the treatment pathway of a cohort of patients with congenital hypodontia requiring a combined orthodontic-restorative dentistry approach; data from a retrospective audit in NHS Tayside will be used as a basis for this discussion. Twenty-one consecutive patients who were assessed on a joint orthodonticrestorative clinic between March 2003 and December 2004 were included. All patients had completed fixed appliance treatment in one or both arches and had commenced or completed the restorative phase of their treatment.

Who receives treatment?


There was a wide age range of patients that were treated following joint consultation between orthodontic and restorative clinicians. The majority of

patients were adolescents, the mean age at the start of treatment when adult patients were excluded was 13 years and 4 months, however, patients were aged between 11 years 4 months and 51 years 3 months. The maxillary lateral incisor was the most common tooth to be absent in this group of patients, with the maxillary upper second premolar being the next most common. Table 1 demonstrates the distribution of the missing teeth in this group of patients. The majority of patients that accepted treatment in the hospital service were missing 1, 2 or more than 6 teeth. Table 2 shows the severity of hypodontia found in these patients: 38% were missing a solitary tooth, whilst patients missing 2 teeth accounted for 24%, with the same number missing six or more teeth. The number of teeth missing ranged from 1−8 teeth with a mean of 3.4 per patient (excluding third molars).

What is the usual patient pathway (Figure 2)? The patient is diagnosed with hypodontia (usually in general practice) and a referral is sent to an orthodontic, paediatric dentistry or restorative dentistry new patient referral clinic in secondary care.

Tooth Type Number of Teeth Missing


Maxillary Lateral Incisor


Maxillary Second Premolar


Mandibular Second Premolar


Maxillary First Premolar


Mandibular First Premolar


Mandibular Second Molar


Mandibular Central Incisor


Mandibular Lateral Incisor


Table 1. Distribution of missing teeth.

Number of Missing Teeth

Number of Patients

1 8 Figure 1. Examples of problems associated with hypodontia. (a) Hypodontia UR2 and associated microdontia of UL2. (b) Mirror image of altered eruption of UL3. (c) Microdontia (LR3), Hypodontia (UR5, UR4, UR3, UR2, LR1, LR2, LR4, LR5), Infra-Occlusion (URE, URD, LRD, LLE), Tipping (LR6).

June 2013

2 5 6 and greater 5 3 2 4 0 5 1 Table 2: Severity of hypodontia.

DentalUpdate 355 © MA Healthcare Ltd. Downloaded from by on September 30, 2017. Use for licensed purposes only. No other uses without permission. All rights reserved.


Referral from GDP, Specialist Practitioner, AVERAGE other secondary care 4 months provider

Orthodontic new patient clinic

RANGE 1–13 months

Restorative Dentistry new patient clinic

4 months

0–19 months

Joint Orthodontic/ Restorative Dentistry clinic 7 months

0–29 months

Orthodontic Treatment Waiting List

Orthodontic Treatment 21 months

6–44 months


Referral to Restorative 6 months

0–23 months

Restorative Treatment 2 months

0.5–6 months

Figure 2. Flowchart of patient pathway through treatment.

The patient is examined, records made and the likelihood of combined care assessed. Treatment in either orthodontics or restorative dentistry is commenced or a review appointment is arranged for the patient to be assessed at a more appropriate stage of dental development or dental health. However, most patients with hypodontia could benefit from combined care and therefore a referral is made to an orthodontic-restorative joint planning clinic. The combined clinic allows the patient to be assessed by both specialties at one appointment. This allows for many treatment options to be fully discussed amongst the clinicians and the patient and his/her family. In addition, the referring specialty has often arranged for special tests

356 DentalUpdate

to be available, for example, appropriate radiographs, study models, Kessling set-ups, diagnostic wax-ups. Orthodontic treatment is commenced after appropriate pre-operative models and written consent is secured. As orthodontic treatment approaches completion, the patient is often reviewed by both specialties to assess tooth and root position, spacing, etc. If both parties agree on the appropriateness of the orthodontic outcome, the patient is appointed for removal of the orthodontic appliance(s) and the patient receives his/her appliance to achieve retention. Referral to restorative dentistry is completed after this, although restorative treatment does not usually begin until 6−9

months after active, orthodontic therapy to allow for maturation of the periodontal architecture. It must be stressed that each patient would have been provided with an orthodontic retainer(s) to wear during this period.

How long does treatment take? The flowchart detailing the time taken for each phase of treatment is shown in Figure 2. The average, total time from the initial joint planning appointment until the completion of both the orthodontic and restorative treatment was over 3 years (38 months), with a range of 15−61 months for the 19 patients who completed both aspects of treatment in the secondary care setting. It demonstrates that orthodontic treatment was completed after a mean of 21 months (range 6−44 months), whilst the restorative phase on average took 2 months (range 2−24 weeks). It must be noted that this restorative phase was usually an intermediate phase using minimally invasive techniques (resinbonded bridges and composite additions) as the patients were generally not of suitable age to commence implant therapy.

Who carries out the treatment? The majority of orthodontic treatment was completed by specialist registrars under the supervision of their consultant(s), whereas most restorative treatments were completed either by a senior house officer (SHO) or a consultant in restorative dentistry. Approximately 10% of patients received their restorative care in primary dental care.

How many appointments are required? The number and type of appointments required to complete each phase of treatment are shown in Figure 3. There were substantially more appointments required for orthodontic treatment. A mean of 17 appointments plus one emergency appointment was required for orthodontic treatment. However, it must be noted that the range of orthodontic June 2013

© MA Healthcare Ltd. Downloaded from by on September 30, 2017. Use for licensed purposes only. No other uses without permission. All rights reserved.



b Orthodontic Appointments

Restorative Appointments





0.8 Scheduled






Emergency 3


Figure 3. (a) The mean number and type of appointments required for orthodontic treatment. FTA = Failed to attend. (b) The mean number of appointments required for restorative treatment. FTA = Failed to attend.


b Orthodontic Treatment 1

Restorative Treatment 2

1 3

11 8




Composite Additions



URA 18

Figure 4 (a) Pie chart of the type of orthodontic appliance used. ULFA = Upper and lower fixed appliances; UFA = Upper fixed appliances; LFA = Lower fixed appliances; URA = Upper removable appliance. (b) Pie chart of the type of restorative treatment provided. RRB = Resin-retained bridge.

appointments needed was from 6 to 30. In contrast, the restorative phase usually (around 50% of the cases) only required 3 or 4 appointments (range 2 to 7). The mean, total number of appointments (orthodontic and restorative) over this period was 23 (range 9 to 34 appointments). This figure has to be regarded with some caution: the number of treatment planning visits was counted as one, however, in many instances there would have been many more, both in the initial single specialty referral, joint treatment planning and subsequent single specialty planning, consent and baseline record stages.

What type of treatment was completed? The type of orthodontic appliance(s) utilized and the restorations placed are shown in Figures 4a and 4b,

358 DentalUpdate

respectively. Almost all patients had fixed orthodontic appliance therapy: 11 of the 21 patients required upper and lower fixed appliances, with 8 patients having upper fixed appliance treatment only. The majority of patients were restored after orthodontic treatment with resin-retained bridges (18 patients). Two patients had both composite additions and resin-bonded bridges, whilst two patients did not complete the restorative phase of treatment.

Discussion For the purpose of this article, the pathway of patients with hypodontia, requiring a combined orthodonticrestorative dentistry approach, has been presented. It should be noted that the data were taken from clinical notes retrospectively and one has to assume that the dates entered were accurate and

therefore the time-scales depicted are truly representative. Some clinical data is described, however, as the number of clinicians involved in care of these patients was relatively large, and no calibration was completed, there could be some inconsistencies. It was interesting to note that the majority of patients that underwent treatment were missing 1, 2 or more than 6 teeth. Table 1 shows that the most commonly congenitally absent tooth in this group was the maxillary lateral incisor. Both reviews of the literature discussed earlier1,3 found the mandibular second premolar to be absent most commonly, but the difference between the epidemiological data and that in this audit can be explained by the fact that treatment is more likely to be sought if a lateral incisor is missing due to the aesthetic problems encountered. The data describes the timescale and pathway of patients through June 2013

© MA Healthcare Ltd. Downloaded from by on September 30, 2017. Use for licensed purposes only. No other uses without permission. All rights reserved.


a combined orthodontic-restorative dentistry approach. However, the patients completed their treatment over eight years ago and many changes have occurred since then: automated reception diaries, changes in personnel and treatment/ referral protocols. In addition, government waiting time targets have been introduced for new patient consultations and time from referral to treatment targets are now common place, as discussed below. If the audit were to be repeated for a cohort of patients today, these changes would likely reduce the initial delay before treatment begins. However, both the length of orthodontic treatment and the delay between orthodontic debond and restorative treatment commencing (to allow for healing/remodelling of the periodontal tissues) would be similar today. Treatment on average took 38 months (involving on average 23 appointments), from the initial joint assessment clinic until the completion of the restorative phase. Patients and their guardians should be aware of the treatment time and that many appointments are required to complete both aspects of treatment. It must be borne in mind that, a study of patient’s undergoing orthognathic surgery found that, when accurate information is given to patients, more satisfaction with overall treatment is observed.7 Patients with hypodontia often have complex orthodontic requirements (large edentulous spaces, lack of alveolar processes, non-coincident midlines, orthodontic anchorage problems). It could be surmised that this would lead to extended orthodontic treatment times. Seventy percent of this group completed their orthodontic treatment within 2 years, which would be considered within the accepted range.8 Restorative treatment time was, on the whole, considerably shorter, with the vast majority of patients having either resin-retained bridgework and/or composite resin additions (examples are seen in Figure 5). No patients received dental implant therapy. It was surmised that this was owing to the relatively young age of the patients who were treated, where implant placement would be inappropriate. If these patients were recalled now, it might be expected that June 2013

several would have had implants placed. If implant therapy is planned, then initial orthodontic treatment can be delayed until the patient is 15 or 16 years old to allow ‘treatment run through’, eliminating the need for intermediate restorations or longer-term wear of removable prosthesis. However, the effect of the malocclusion on the patient’s current quality of life has to be considered. Delaying treatment may also interfere with future education and examinations and, in addition, the patient may move away from the area, thus complicating care even further. Having discussed all of these issues, the patient/ parent can make an informed decision as to when he/she wishes treatment to commence. The majority of patients that were treated had 1 or 2 teeth missing (61% of patients in this cohort). A systematic review3 revealed that 83% of patients with hypodontia were missing 1 or 2 teeth. This difference may indicate that some patients missing only 1 or 2 teeth are not seeking treatment, or that they are being treated solely in a primary care setting. Alternatively, the data from the systematic review was taken from the Caucasian populations in North America, Australia and Europe, but differences were found across these continents and therefore the proportion missing 1 or 2 teeth may have been different in our sample population. Most orthodontic treatment was provided by specialist registrars. This may be a result of the greater number of orthodontic specialist registrars compared to restorative dentistry (currently in Scotland there are 9 orthodontic specialty registrars and 3 post-CCST trainees but only 8 trainees in restorative dentistry). Restorative care was generally provided by either SHOs or by consultants in restorative dentistry. This difference may reflect the complexity of the different treatments. For example, straightforward restorative treatments, like composite additions or resin-retained bridgework, would be completed by more junior members of staff, but more complex treatment would more likely be completed by a consultant member of staff. Alternatively, a shortage of an appropriately trained workforce employed in the departments may have necessitated these differences. This data compares favourably



Figure 5 (a) Example of a patient who received composite additions to treat congenital absence of maxillary lateral incisors. (b) Example of a patient who received a resin-retained bridge to treat congenital absence of the upper right maxillary lateral incisor.

with a survey of all the orthodonticrestorative cases in an NHS hospital,9 that indicated that the majority of orthodontic treatment was completed by FTTAs, whilst most of the restorative procedures were completed by consultants. It is important that communication and the referral process between primary and secondary care and between the dental specialties is reliable to ensure that the patients are transferred at the appropriate time. It is therefore essential that a pre-debond examination completed by both the orthodontic and restorative teams is completed. If this is not completed, it could have an adverse effect on the outcome and may possibly lead to orthodontic appliance therapy being re-commenced to create or reduce the amount of space present. If implant therapy is planned, it is important that orthodontic treatment has created a sufficient mesio-distal width to allow implant placement in line with biological principles. A Kessling set-up can be used in the assessment of these dimensions and is often used in planning, regardless of the intended restorative treatment. In addition, the roots of the teeth adjacent to DentalUpdate 359

© MA Healthcare Ltd. Downloaded from by on September 30, 2017. Use for licensed purposes only. No other uses without permission. All rights reserved.



Figure 6. Implant placement would be impossible in this case owing to the mesial inclination of the canine root.

360 DentalUpdate


degree and presence of relapse was dependent on the type of orthodontic appliance used (fixed appliance or URA). If retainers are not worn, then tooth movement can occur and can result in poor aesthetic appearance (Figure 7a). For this reason, immediately following the completion of restorative treatment a vacuum-formed orthodontic retainer (Essix retainer) is made to fit over the completed restorations (Figure 7b). Following this audit, some local recommendations were made:  Consent for orthodontic treatment should advise that treatment will last for 2 years, but around one-third of patients will take longer;  All patients should have a pre-debond check by both the orthodontic and restorative consultants;  Clearer communication (by letter) between the different phases of treatment is recommended; and  The necessity of life-long orthodontic retention should be emphasized to prevent relapse. In summary, patients and their guardians should be informed that treatment may be complex, requiring excellent compliance, both with respect to oral hygiene measures and attendance. The average time from the first new patient consultation until the end of treatment was approaching four years, with at least 23 appointments; fixed appliance therapy in both arches was usually required and restoration following orthodontic treatment was usually with resin-retained bridgework and/or composite resin additions in the younger patient cohort.

the implant site should, as a minimum, be parallel or, ideally, slightly divergent (Figure 6). The treatment of this cohort of patients was commenced in 2003/2004, prior to waiting time directives for new patient consultations and any subsequent treatment. The average delay until a new patient consultation was 4 to 5 months; this breaches the current waiting time directive. If the time until a combined clinic appointment (mean of 8−9 months) is considered, this indicates a substantial delay and reflects the complexity of these cases and the demand for joint clinic appointments. The time lag between the assessment visit and the start of treatment is accounted for by the complex treatment planning procedures often required, lack of staff and the length of the existing treatment waiting list. Recent advances in the local service provision has reduced the orthodontic treatment waiting list time considerably and efforts are underway to reduce the wait time for both restorative dentistry appointments and joint clinic appointments. Whilst enhanced communication between the orthodontic and restorative specialties has enabled restorative treatment to commence at the appropriate time (approximately 6 months after orthodontic debond), this is despite the relatively long restorative dentistry waiting list. Orthodontic retention is discussed with all patients as there is a risk of relapse after treatment. Fox and Chadwick10 found that 61−100% of all orthodontic cases had a ‘deterioration of (their) occlusion’ at least 1 year after all retention measures had ceased. The

1. Larmour CJ, Mossey PA, Thind BS, Forgie AH, Stirrups DR. Hypodontia − a retrospective review of prevalence and aetiology. Part I. Quintessence Int 2005; 36: 263−270. 2. Locker D, Jokovic A, Prakash P, Tompson B. Oral health-related quality of life of children with oligodontia. Int J Paediatr Dent 2010; 20(1): 8−14. 3. Polder BJ, Van‘t Hof MA, Van der Linden FP, Kuijpers-Jagtman AM. A meta-analysis of the prevalence of dental agenesis of permanent teeth. Community Dent Oral Epidemiol 2004; 32(3): 217−226. 4. Cobourne MT. The genetic control of early odontogenesis. Br J Ortho 1999; 26: 21−28. 5. Gullikson JS. Tooth morphology in rubella syndrome. J Dent Child 1975; 42: 479−482. 6. Jones JW. A medico-legal review of some current UK guidelines in orthodontics: a personal view. Br J Orthod 1999; 26(4): 307−324. 7. Cunningham SJ, Hunt NP, Feinmann C. Perceptions of outcome following orthognathic surgery. Br J Oral Maxillofac Surg 1996; 34(3): 210−213. 8. Mavreas D, Athanasiou AE. Factors affecting the duration of orthodontic treatment: a systematic review. Eur J Orthod 2008; 30(4): 386−395. 9. Sayers MS, Banner AJ. A survey on orthodontic-restorative dental services in a NHS hospital. Eur J Prosthodont Restor Dent 2008; 16(2): 56−60. 10. Fox NA, Chadwick SC. The first 100 cases of orthodontic treatment: one year out of retention. Dent Update 1994; 21(7): 294−297.


Figure 7. (a) The patient stopped wearing her retainer after 2 years and was now disappointed with the aesthetic appearance. Substantial relapse is observed. (b) Essix retainer and the model with which it was fabricated.

June 2013 © MA Healthcare Ltd. Downloaded from by on September 30, 2017. Use for licensed purposes only. No other uses without permission. All rights reserved.

The orthodontic-restorative interface in patients with hypodontia: the patient's journey.

Congenitally absent teeth may pose aesthetic and functional problems for patients. Treatment is often complex and involves a multidisciplinary team. U...
269KB Sizes 0 Downloads 0 Views