From Volume 5, Issue 3, July 2012 | Pages 70-76
This second article aims to outline the role of combined paediatric dentistry-orthodontic planning in the management of complex cases of the developing dentition. Case studies have been used to highlight those patients who would most benefit from such a combined approach.
Following a six-month survey of joint paediatric-orthodontic clinics (CDHCC – Child Dental Health Consultant Clinic), it became evident that over a third of patients presented to these clinics with uncommon yet complex needs. The cases ranged from those with delayed or unerupted teeth, abnormalities of tooth size and form, as well as those with complex medical needs. This article will highlight some of those cases.
Dental infra-occlusion has been defined as when teeth are below the occlusal plane. Infra-occlusion is usually associated with primary molars.1 It is also frequently associated with ankylosis, which is a direct bony union between tooth and bone. The infra-occluded deciduous molars are believed to remain static while the adjacent teeth move vertically with growth and development of the alveolar process.2 The exact aetiology of infra-occlusion is unknown but a number of possible causes have been identified:
The prevalence of infra-occluded primary molars ranges from 1.3–38.5%. The use of differing diagnostic criteria, such as ages of patients in the sample groups, account for the large variation of prevalence.8,9 It appears that mandibular first deciduous molars are the most frequently affected teeth, followed by the mandibular second and maxillary second deciduous molars, respectively.10 Infra-occlusion usually occurs in the mixed dentition stage.11 The possible effects on the developing occlusion are as follows:
Management of infra-occluded deciduous teeth depends on the severity of infra-occlusion and the presence or absence of the permanent successor. The severity of infra-occlusion is usually measured by the relation of the crown of the infra-occluded tooth with the contact points of the adjacent teeth. Evidence suggests that, when infra-occlusion is not too severe and the permanent successor is present and in a normal position, these teeth will usually exfoliate albeit with a short delay of six months.6 Infra-occluded deciduous teeth without permanent successors do not often exfoliate. If left in situ, root resorption might continue and an impaired vertical position might occur due to the ankylosis. This development might be slow after 12 or 13 years of age. Kurol11 explains that the problem facing the clinician is often predicting which ankylosed teeth will, with time, have good bone support, minimal infra-occlusion and good roots. It is recommended that a mildly infra-occluded tooth can be restored with a stainless steel crown or composite resin build-up to help prevent the tipping of the neighbouring teeth, as well as preventing over eruption of the opposing teeth. Generally, early infra-occlusion in a growing child with the absence of a permanent successor is an indication for extraction.2
Occasionally, the infra-occlusion is so severe that the deciduous tooth is at gingival level, resulting in tipping of adjacent teeth. Its removal can necessitate the loss of surrounding teeth in order to gain access for its extraction leading to more significant potential space loss. An option in these cases is to consider the orthodontic alignment of adjacent teeth to facilitate extraction and then space maintenance. The following two cases illustrate this approach.
IB was a fit and healthy 12-year-old female who was referred by her general dental practitioner to the paediatric department of Bristol Dental Hospital regarding an infra-occluding upper left second deciduous molar (ULE). She presented in her late mixed dentition phase complicated by infra-occluded lower second deciduous molars (LRE and LLE) and upper left second deciduous molar (ULE). Clinical and radiographic examinations revealed the presence of all permanent teeth (Figures 1 a–e and 2).
In order to facilitate the extraction and eruption of the permanent successors, it was decided to distalize the upper left permanent molar (UL6) with a removable appliance (Figures 3–5).
It was assessed that this patient could be treated on a non-extraction basis and, if UL5 could be allowed to erupt into the arch, then further appliance treatment may not be necessary. It was planned to space maintain post-operatively with a simple removable appliance while awaiting the eruption of the second premolar.
AM was a fit and healthy 5-year-old male patient referred to the orthodontic department of Bristol Dental Hospital regarding infra-occluding lower right second deciduous molar (LRE). This tooth, although deemed as a problem, was not extracted at this stage owing to the possibility of damage to its developing successor (Figures 6 a–c and 7). Arrangements were made to review him in a year's time on the CDHCC.
At this stage, the lower right first permanent molar (LR6) had significantly tipped mesially. It was decided to upright and distalize this tooth orthodontically prior to the extraction of the infra-occluding tooth (Figures 8 a, b and 9). This phase of treatment was completed in six months. LRE was extracted and a band and loop retainer was fitted to allow eruption of the lower right second premolar (Figure 10 a, b).
Even at this early stage of dental development it was assessed that, potentially, AM had an occlusion that would not require extensive appliance intervention if the space for the LL5 could be maintained. With this in mind, it was felt that a short course of limited fixed appliance treatment at this young age was appropriate.
Excessive mesio-distal width of a clinical crown might indicate a dental fusion or gemination. Dental fusion is characterized by the partial or complete union of the dentine and/or the enamel of two or more separate teeth at some stage of development. Fusion may occur between teeth of the same dentition or between supernumerary teeth. Clinically, ‘double’ teeth present as broad crowns with a vertical groove extending toward the gingival sulcus. The pulp chamber and the root canals can be joined or separated. The aetiology of these teeth is unclear, although they can cause a number of problems:12
The treatment of ‘double’ teeth includes extraction, endodontic treatment and sectioning of the tooth, orthodontic treatment or a combination of treatment. It is in the management of these cases where the combined paediatric-orthodontic input can be invaluable to preserve a healthy dentition and restore aesthetics. This interaction is demonstrated in the following case.
JU was a fit and healthy 9-year-old male patient referred by the specialist orthodontic practitioner to the department of paediatric dentistry of Bristol Dental Hospital regarding malformed upper central incisors. He was assessed on the joint paediatric-orthodontic clinic. Clinical and radiographic examinations revealed a Class II div 1 malocclusion on a Class 1 skeletal base, with average lower anterior face height and mildly incompetent lips. The upper central incisors were enlarged due to the fusion of these teeth with bilateral supernumeraries involving the full length of the roots. The upper lateral incisors and permanent canines were crowded buccally. The initial plan involved the aesthetic improvement of these teeth using composite additions. JU was reviewed once more on the joint clinic at 11 years of age. The plan at this stage was to fit a space maintainer and remove the crowded upper lateral incisors to allow the upper canines to erupt more mesially next to the double teeth (Figures 11 and 12 a–d).
JU will still require restorative maintenance in the future and continued monitoring of his malocclusion. However, he has an acceptable appearance in the interim before further possible definitive treatment.
In the United Kingdom, there are approximately 1,200 new cases of childhood cancer each year.13 Up to 90% of the paediatric oncology patients may suffer oral complications, with implications for longevity and quality of life during and after therapy. The oral cavity is a site where complications frequently develop as a direct result of the malignancy or as an unwanted effect of treatment.14 Child cancer patients largely reflect the child population in general since they represent a cross-section of the population. The survival rates following cancer treatment has significantly improved in the last three decades. Therefore, dentists are increasingly likely to find that they have children in their care that may have been treated for malignant disease.15
Treatment of cancer is approached in one or more of the following ways; chemotherapy, radiotherapy, a combination of both or, in the case of more solid tumours, surgery. Bone marrow transplantation (BMT) using marrow ablative doses of chemotherapy or chemoradiotherapy, followed by an infusion of hematopoietic stem cells, are being used in an increasing number of children as treatment of malignant and non-malignant disorders. Radiotherapy is also often used as an adjunct to bone marrow transplantation and may involve total body irradiation to kill all the bone marrow cells, including the leukaemic cells. Following this, bone marrow cells from the donor are transplanted.
Most chemotherapeutic agents have selective toxicity towards tumour cells. However, some damage to normal tissues is inevitable. The cytotoxic action of these drugs affects the odontoblasts, which are the cells responsible for laying down dentine. However, cells in the non-proliferative, germinal stages are unaffected.16 Because of the short half life of most chemotherapeutic drugs, dental defects are usually localized, resulting from transient changes in the odontoblast function instead of odontoblast death. Dental defects attributed to chemotherapy include arrested root development, inhibition of dentine formation and enamel defects.17,18 Narrow pulp chambers, localized enamel defects and shortened thin roots are some of the consequences of chemotherapy.
Radiotherapy is employed to eradicate the malignant cells with minimal damage to normal tissue. The short-term complications (0–2 months) of radiotherapy to the head and neck region are:
In the long term, these patients may have orofacial asymmetry, tooth agenesis, enamel hypoplasia, arrested root development, osteoradionecrosis and pituitary insufficiency, thereby giving rise to growth defects.19 Dentists should play a significant role in the team that manages childhood cancer. Long-term follow-up by the MDT clinic, often indicated as ‘orthodontic treatment’, is focused around management of the developing dentition with an interceptive approach to limit the need for the use of appliances.
ET was a female patient diagnosed with rhabdomyosarcoma when she was 18 months of age. The tumour was excised surgically and chemotherapy was commenced. Owing to a low neutrophil count, she was given only 44% of the usual regime of chemotherapy. At six years of age, ET was seen in the paediatric dentistry department of Bristol Dental Hospital following a referral from her general dental practitioner. On presentation, she had a Class III malocclusion and was in her mixed dentition with a carious lower left permanent molar (LL6) and missing lower second premolars. Her first premolars were diminutive. She also had upper arch crowding and crossbite associated with the UR2 (Figures 13 a–e and 14).
After undergoing acclimatization, prevention and restoration of LL6 in paediatric dental clinic, she was seen on the CCDH where a decision was made to extract the diminutive upper first premolars, correct the single tooth crossbite with a removable appliance and, subsequently, fixed appliances were used to increase the space for the UL5 to erupt (Figures 15 a–e and 16).
Unfortunately, the sealant restoration initially undertaken in the LL6 had subsequently partially failed and there was further caries development in this tooth. This tooth has now been permanently restored.
ET is still undergoing joint review at the present time to monitor her Class III skeletal growth. The lower diminutive premolars remain unerupted, although they are maintaining alveolus in the area.
Regional odontodysplasia (RO) is an uncommon anomaly of unknown aetiology in which the development of one or several teeth in a localized area is adversely affected.20 Generally, the disturbance is localized to one arch and the maxilla is involved twice as often as the mandible.21 Clinically, the affected teeth are atypically shaped with surface pits and grooves, hypoplastic, hypocalcified and show yellow/brown discoloration.22 The eruption of the affected teeth is delayed or does not occur at all.23 Radiographically, the affected teeth show abnormal morphology. The enamel and dentine are less radio-opaque than unaffected counterparts and there is little demarcation between enamel and dentine.24 Pulp necrosis is often noted as a result of the communication with the oral cavity through the dentinal clefts and pulp horns.25 Diagnosis of RO often coincides with the eruptive periods of the primary and permanent teeth, the main patient concerns being delayed eruption or a non-inflammatory gingival swelling in the area close to the affected teeth.26 Some may even present with pain and abscesses, which have been attributed to bacterial access to the pulp through clefts in the defective enamel and dentine.27
Management of RO remains controversial. Some authors advocate early extraction of the involved teeth as it is presumed that, if they erupt, they would display defective enamel and have undesirable aesthetics.28 Others believe that removal of teeth in a young child may not only lead to undesirable psychological effects, but also a significant reduction in alveolar ridge height, resulting in difficulties for future restorative treatment.21 A case of RO which was followed radiographically for six years demonstrated the ability of these teeth to show continued dentine formation and a relative normalization of the pulp and roots.29
It is recommended that, if the teeth affected by RO erupt and are functional, then they should be retained wherever possible.30 If orthodontic treatment is then indicated and the affected teeth are to be moved, low forces will be required as the roots are often short and the surrounding bone has lower density.31 Before any treatment commences, the team need to consider factors such as age of patient, the number of affected teeth, the presence or absence of any pathology, as well as the attitude and wishes of the child and parent.32 Again, the combined approach to planning these cases can try to encourage spontaneous alignment or help plan for alignment and restorations in the long term.
HG was a 15-year-old patient who presented with a Class II div 1 malocclusion on a mild skeletal Class II base with mild crowding in her lower arch and moderate crowding in the upper arch. The overjet was increased at 7 mm. There was an unusual pattern of hypoplasia affecting all the incisor teeth and the posterior teeth on the right-hand side. The UR4 was carious as well as being significantly hypoplastic (Figure 17 a–e).
The patient was referred for combined planning and it was decided to undertake upper and lower fixed appliance treatment, extracting the UR6 and both upper first premolars. Following the completion of orthodontic treatment, definitive restoration will be undertaken to improve the appearance of the anterior teeth and longevity of the posterior teeth.
In summary, we have tried to demonstrate the advantages of undertaking combined paediatric dentistry-orthodontic planning in some of the more challenging cases that present in our surgeries.
Working together and viewing the issue from different angles can facilitate excellent outcomes in these young patients.
