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Consultant in Orthodontics, University of Manchester Dental Hospital, Higher Cambridge Street, Manchester, M15 6FH, Salford Royal NHS Foundation Trust, Stott Lane, Manchester and Northenden House Orthodontics, Sale Road, Manchester, M23 0DF
Adult patients are increasingly seeking orthodontic treatment. It is essential to establish optimal periodontal health in these patients before embarking on such treatment, which demands the interaction between the general dental practitioner (GDP) and orthodontist for effective management. This article focuses on the management of periodontal disease in orthodontic patients, orthodontic considerations, retention and complications that may arise. This is demonstrated throughout a series of clinical cases treated within a multidisciplinary team. The management of patients with periodontal disease is often challenging; the clinical issues that require consideration are discussed throughout this article.
CPD/Clinical Relevance: This article provides a summary of the orthodontic and periodontal implications of different treatment techniques and management for the general practitioner.
Article
Adult patients are increasingly requesting orthodontic treatment. An epidemiological study at the Eastman Dental Hospital revealed that the number of adults undertaking orthodontic treatment has increased significantly, especially since 1985.1 This may be due to social acceptability of appliance therapy, with the main motivation of adult patients being the desire to improve their dental appearance.2
Adults can be excellent candidates for orthodontic treatment. They are motivated and co-operative, however, consideration must be given to the periodontal condition in this group of patients. Periodontitis is a common problem in adults. It has been found that 72% of adult patients have at least one site with clinical attachment loss (CAL) equal to or more than 3 mm.3 Furthermore, the cumulative impact of periodontal challenges over a lifetime may result in older patients having more CAL.
Though plaque has a significant role in the aetiology of periodontal disease, the seminal work of Löe and colleagues4 demonstrated that plaque alone is not the critical factor in disease progression. There is a complex interaction in the subgingival environment between disease-causing bacteria, their numbers and virulence within the biofilm and the host inflammatory response.5 It is this inflammatory response that results in the collateral damage of tissue breakdown.6 Many risk factors have been identified that may influence periodontal disease progression which are listed in Table 1.
Systemic
Local
Diabetes
Poor oral hygiene
Decreased immunity, eg Leukaemia, HIV/AIDS
Poorly contoured dental restorations
Smoking
Plaque
Hormonal changes
Calculus
Genetics
Gingivitis
Age
The destruction of bone, periodontal ligament and connective tissue fibres joining adjacent teeth has a significant role in stabilization of the tooth position within the soft tissue environment.7,8 Loss of this connective tissue attachment can lead to drifting, tilting or rotation of teeth (Figure 1).
Figure 1. Patient presenting with proclined incisors, spacing and drifting of teeth.
Periodontally compromised patients often present with:
Mobile teeth;
Proclined incisors;
Spacing due to drifting of teeth or early loss of teeth;
Rotations;
Overeruption of teeth.
It is essential that referring practitioners control periodontal disease before referral. The signs of periodontal disease include:
Presence of plaque or calculus with inadequate oral hygiene;
Subgingival calculus;
Recession;
Bleeding on probing (BOP);
Mobility;
Radiographic evidence of alveolar bone loss;
Probing depths >4 mm (CAL).
However, especially for those patients that self-refer into orthodontic practices, it is important that orthodontists undertake a basic periodontal examination (BPE) on new patients to screen for disease. Should a formal diagnosis of chronic periodontitis be made, any orthodontic ambitions must be put on hold and the disease investigated. It is imperative to liaise with the patient's GDP at this point. The GDP should pick up the referral with a thorough patient examination including BPE, radiographs and, if necessary, a six point periodontal chart. The choice of radiograph is dependent upon extent of disease and the improved diagnostic yield of vertical bitewings and selected periapicals over orthopantomograms cannot be understated. The British Society of Periodontology updated its guidelines in 2016 indicating that all BPE code 3 and 4 sextants should have relevant radiographs.9 The Faculty of General Dental Practice (FGDP) indicates that vertical bitewings should be taken when a patient has pocketing of more than 6 mm (BPE score 4), which should be supplemented with periodical radiographs at sites where alveolar bone image is not included.10
Periodontal management prior to orthodontic treatment
The sequence of disease management includes three fundamental stages:
Cause-related therapy (initial therapy);
Corrective therapy;
Supportive periodontal therapy (maintenance).
Cause-related therapy
This includes patient education, motivation, oral hygiene instruction and smoking cessation advice. This instruction phase underpins the success of any future care and cannot be underestimated. From here, removal of subgingival plaque and calculus with targeted root surface instrumentation of all pockets >3 mm should be performed. This should be undertaken with local anaesthetic over multiple visits. It also important to identify and remove any plaque retentive restorations. Once completed, no further probing should be undertaken until a review (for 6-point charting and bleeding on probing) in 2–3 months, depending upon risk factors.11 On review, an absence of bleeding on probing is suggestive of disease stability.12
Corrective therapy
If, after initial therapy, the oral hygiene has improved but there are some isolated, residual active periodontal pockets, these may benefit from more targeted treatment. Further non-surgical treatment could be undertaken using site-specific curettes but, when residual pockets exceed 6 mm and show disease activity with bleeding on probing, it may be necessary to consider surgical instrumentation.13 Surgery allows the following:
Access for root surface instrumentation;
Modification of gingival morphology to improve plaque control; and
Facilitation of pocket reduction via healing with long junctional epithelium or simply by recession.
Surgery should not be considered in patients with poor oral hygiene, smokers or medically compromised patients.
Supportive periodontal therapy
Following active treatment, maintenance therapy must be planned for the patient. This will involve targeted instrumentation of residual pockets and bleeding sites, reiteration of oral hygiene and continued motivation. The intervals for supportive periodontal therapy should be based upon patient risk factors.11 The GDP should aim for pocket depths less than 5 mm without bleeding and bleeding and plaque scores less than 15%; ideally BPE scores of 0. By definition, many patients requiring orthodontic treatment will have imbrications and crowding automatically generating BPE scores of 2, as crowding automatically generates a plaque retention factor.
Periodontal screening for children and adolescents assesses six index teeth (UR6, UR1, UL6, LL6, LL1 and LR6) using a simplified BPE to avoid the problem of false pockets.14 BPE codes 0–2 are used in the 7-to 11-year-olds, while the full range of codes 0, 1, 2, 3, 4 and * can be used in the 12-to17-year-olds.
Once the GDP is satisfied that the periodontal disease is under control, consideration can then be given for orthodontic treatment, an example of which is shown in Figure 2. If the GDP feels that specialist support is necessary to control the periodontal disease, the British Society of Periodontology has published useful guidance and levels of complexity for when to refer a patient. A referral should be made to a specialist when there is severe horizontal alveolar bone loss (>50%) with evidence of true pocketing of 6 mm or more.15
Figure 2. Patient who has undergone periodontal treatment and is now ready for orthodontic treatment. Note the excellent oral hygiene and healthy gingivae.
Alternatives to orthodontic treatment should be explored with the patient. This may include restorative camouflage with directly bonded restorations and/or extraction of more severely displaced teeth.
Orthodontic considerations
In patients with stabilized periodontal disease, it is critical to maintain effective plaque control, therefore it is ideal to keep appliances and mechanics simple. Placement of a fixed orthodontic appliance can induce plaque accumulation due to the difficulty of cleaning adequately around bands and brackets. A study comparing the microbial populations before and after orthodontic treatment showed that all bacterial categories increased in number after fixed appliance placement. It was also found that the greater the number of orthodontic auxiliaries, the greater the increase in microbial populations.16
Considerations should be given to:
Avoiding hooks, elastics and excessive composite following bracket placement;
Wire ligatures should be used where possible instead of elastomeric modules;
Consider bonds/tubes on molar teeth instead of molar bands (Figure 3a, b) Throughout treatment it is important for the patient to continue to see the GDP or hygienist for regular 3-monthly scaling and maintenance with a full periodontal re-examination every 6-months. Close communication is essential between orthodontist and GDP and patients should be warned that appliances will be removed if oral hygiene and/or periodontal disease deteriorates.
Figure 3. Case demonstrating molar tubes being used to avoid gingival overgrowth (a) in comparison to (b) in which bands have been used, leading to overgrowth of gingivae.
Orthodontic mechanics often need to be adapted for patients with previous periodontal disease. Where there is a reduced periodontium, there is a reduced periodontal ligament (PDL) surface to receive orthodontic forces. The centre of resistance of the tooth is displaced more apically and therefore there is an increase in the extrusive component of the applied force. This has been demonstrated in Figure 4. Teeth tend to tip rather than move bodily due to the repositioning of the centre of resistance. The use of a light force and rigid working archwire will reduce this tendency.
Figure 4. Diagram to illustrate the apically repositioning of the centre of resistance following periodontal disease which has led to reduced periodontal support.
Reduced periodontal support with the same force against the crown produces greater pressure in the PDL, therefore lighter orthodontic force should be used to move teeth with reduced periodontal support to reduce the risk of undermining resorption.
Correcting an increased overbite in adult patients can be challenging. Since adults lack growth potential, any attempt to correct the overbite by extruding posterior teeth will not be stable and will risk further reduction of periodontal support of molar teeth. Overbite reduction can be achieved either by surgical methods (segmental osteotomy) or orthodontic methods alone (intruding anterior teeth).
Utility arches such as the Burstone arch can reduce overbite by relative intrusion of anterior teeth. Care should be taken to avoid extrusion of molars. Temporary Anchorage Devices (TADs) inserted at the posterior region can be used to prevent the extrusion of molars. TADs can also be used directly to intrude anterior teeth. When TADs are inserted between incisors they should have a low profile so that the direction of traction is not labial to the crown surface to prevent proclination of incisors during intrusion.
Orthodontic consent
The consent process is extremely important for patients with previous periodontal disease. Risks discussed should include:
Risk of disease progression and risk to dental health;
Treatment outcomes may be limited;
Stopping treatment early if periodontal disease becomes active;
Enforced extractions;
Longer treatment time;
Relapse.
Orthodontic retention
Orthodontic retention is a crucial part of any orthodontic treatment, but particularly important for teeth that have been periodontally involved, as the potential for relapse is high. A long-term permanent (bonded) retainer prevents relapse by maintaining alignment, but allows some physiological movement. However, this bonded retainer should be cleanable to prevent plaque accumulation and allow adequate oral hygiene.
Orthodontic complications
Complications that can arise following orthodontic treatment in the periodontally compromised patient can include gingival inflammation, gingival recession, alveolar bone loss, dehiscences, fenestrations, black triangles forming between incisor teeth and root shortening. Figure 5 shows gingival defects and mucogingival surgery. Complications can be minimized by ensuring patient factors are addressed and monitored alongside careful orthodontics.
Figure 5.
(a, b) Gingival defect and mucogingival surgery.
Case 1
The following case shows pre- and post-treatment images of a 58-year-old female who presented with periodontal disease. The patient was keen to improve her smile with orthodontic treatment. She presented with crowding in the upper and lower arches with rotation of the lower left canine and drifting of the upper left lateral incisor (Figures 6 a–e).
Figure 6.
(a–e) Case 1: Pre-treatment intra-oral images of 58-year-old woman who presented with periodontal disease.
After a period of periodontal and restorative treatment from the patient's GDP, orthodontic fixed appliances were commenced (Figures 7a–c). The final result is shown in Figures 8a–e, which was a compromised finish with some areas of gingival recession and black triangles present between incisors and premolars. However, the patient was extremely happy, with the final result improving her self-confidence.
Figure 7.
(a-c) Case 1: Molar tubes were used to avoid gingival ovegrowth. A push coil was used in the lower right quadrant to create space for the lower right second premolar with a premolar extraction in the lower left quadrant. The patient maintained an excellent standard of oral hygiene throughout.Figure 8.
(a-e) Case 1: Post-treatment views. Upper and lower bonded retainers placed to avoid relapse.
Case 2
The following case shows pre- and post-treatment images of a 47-year-old female who had a previous history of periodontal disease (Figures 9 a–e). The pre-treatment OPG radiograph in Figure 10 shows moderate horizontal alveolar bone loss, particularly in the lower incisor region. The patient maintained an excellent standard of oral hygiene so treatment involved extraction of the maxillary second premolars and fixed appliances.
Figure 9.
(a–e) Case 2: Pre-treatment intra-oral views.Figure 10. Case 2: Pre-treatment OPG radiograph showing moderate horizontal bone loss.
Figures 11 a–e shows the final result, which is a compromise. However, the patient was extremely happy with the result. This case shows an example of the standard of oral hygiene expected throughout treatment and how an excellent result can still be achieved.
Figure 11.
(a–e) Case 2: Post-treatment views. Upper and lower bonded retainers placed to avoid relapse.
Summary
This article has described the different orthodontic treatment techniques and considerations when undertaking orthodontic treatment in patients following appropriate periodontal management. It is imperative to ensure that any patient with periodontal disease has had successful periodontal treatment before embarking on a course of orthodontic treatment.
