Volume 33 (2017): Issue 2 (January 2017)

Timely referrals of appropriately screened cases are essential for the effective delivery of orthodontic treatment. Dental therapists are intimately involved with the orthodontic screening process in New Zealand, given that they are the primary oral health providers for child and adolescent patients.

(1) To investigate New Zealand dental therapists’ orthodontic screening and referral practices; and, (2) to quantify the perceived need for supplementary orthodontic resources by New Zealand dental therapists.

An online questionnaire was distributed via email to 659 actively practising dental therapists in New Zealand. Participants answered questions related to their socio-demographic characteristics, orthodontic screening and referral practices, and further orthodontic education.

All surveyed dental therapists viewed orthodontics as an important treatment priority. Most (64.6%, N = 148) agreed that the orthodontic screening process should be a joint undertaking between general dental practitioners and dental therapists. Most practitioners (63.3%, N = 145) had access to (and used) an orthodontic screening guideline. While almost all dental therapists (98.7%, N = 226) were confident in assessing cases that were suitable for orthodontic referral, 63.8% felt that they could gain from further education, and virtually all (99.6%, N = 228) believed that continuing professional development (CPD) courses in orthodontics would be beneficial. Over three-quarters were in favour of a standardised national guideline for orthodontic screening, while the remainder were either satisfied with their current guidelines (15.3%, N = 35) or believed that such guidelines were unnecessary (7.0%, N = 16). Several patterns were observed by therapist characteristics, particularly related to working sector (private or public) and length of professional experience.

There were differences in the orthodontic screening and referral practices of dental therapists in New Zealand. Dental therapists were receptive to the idea of standardised guidelines for orthodontic screening and there was a perceived need for CPD courses in orthodontics.

The present multicentre study assessed the prevalence and patterns of impacted and transmigrated maxillary and mandibular canines in a Turkish subpopulation.

The study identified 1625 patients who had impacted teeth from a group of 10,700 patients (referred to three university hospitals between January 2014 and December 2015) and examined the accompanying records, panoramic and periapical radiographs, and cone-beam computed tomographic images (if available). An impacted canine was considered to be transmigrated when at least part of the tooth had crossed the midline.

Out of 1625 patients, 163 (10.0%) had impacted canines (comprising a total of 170 affected teeth). Impacted canines were found in the maxilla in 114 patients (69.9%) and 49 patients (30.1%) showed mandibular canine impaction. Thirty-eight patients (2.3%) had transmigrated canines, of which twenty (52.6%) were located in the mandible, while 18 (47.4%) were found in the maxilla. No significant difference was evident between the genders, the site (right/left) and the impacted/transmigrated canines (p > 0.05). However, it was determined that canine impaction was significantly more frequent in the maxilla than in the mandible (p < 0.05). In addition, of the 38 patients presenting with transmigrated canines, eight (21.6%) had a history of alpha thalassemia.

Canine transmigration occurs in both the mandible and maxilla. The prevalence of impacted/transmigrated canines in the studied population was 10.0% and 2.3%, respectively. The mechanism of transmigration of maxillary canines remains unclear and requires further investigation. However, a possible correlation with genetic disorders (like alpha thalassemia) should not be overlooked.

Orthodontically-induced inflammatory root resorption (OIIRR) is an unwelcome side effect of orthodontic treatment. Mechanical vibration has been suggested as a preventative measure but evidence is limited. The aim of this study was to investigate whether whole body mechanical vibration has a positive influence on OIIRR.

Thirty-six 10-week-old Wistar rats were divided into three groups, which received either 30 Hz vibration, 60 Hz vibration or no vibration to serve as a control group. A heavy mesial force of 100 g was applied to the left maxillary first molar using nickel-titanium closed-coil springs. The right maxillary first molar served as an internal control. The vibration groups received 30 Hz or 60 Hz of whole body vibration for 10 minutes per day for 14 days. A volumetric analysis of the extent of root resorption on the mesial-buccal root of the first maxillary molar was examined using micro-computed tomography.

When compared with the control group, the animals that received 30 Hz (p = 0.21) and 60 Hz (p = 0.16) of mechanical vibration did not show a statistically significant reduction in OIIRR. The results did not show a statistically significant difference in the extent of OIIRR between 30 Hz and 60 Hz vibration groups (p = 0.78).

Mechanical vibration at 30 Hz and 60 Hz, when applied in an experimental model of whole body vibration, showed no significant effect on either physiological root resorption or OIIRR in rat molars loaded by a heavy orthodontic force.

To seek information regarding the relationship between the quantity of alveolar bone and the angle and sagittal position of the incisors. This was to be further determined in relation to the basal bones and facial pattern with the aim of establishing a predictive model based on the study of a lateral cephalogram.

The distance from the cemento-enamel junction to the labial alveolar crest and the bone thickness half-way along the root of the most prominent upper and lower incisor were measured in a sample of 100 cone beam computed tomography (CBCT) scans of patients aged between 15 and 34 years. Lateral cephalograms of the patients were extracted from the scans and used to measure the buccolingual angle and antero-posterior position of the incisors in addition to the facial pattern of each patient.

A correlation was found between bone thickness around the upper incisor and the variables of the incisal angle and its sagittal position. The inclination of the lower incisor (IMPA) was related to cortical bone thickness. The cemento-enamel junction to alveolar crest measurement (bone height) was related to the antero-posterior position of the lower incisor in men. The facial pattern was unrelated to any of the variables.

The angle and sagittal position of the upper and lower incisors were associated with alveolar bone thickness in men. Only the antero-posterior position of the lower incisor was related to its alveolar bone height. In women, only the angle of the lower incisor was associated with bone thickness.

The assessment of hand-wrist films to identify skeletal maturation stage is a commonly used method for the determination of the status of a growing patient. However, there is limited information available regarding skeletal growth evaluation in subjects with a unilateral cleft lip and palate (UCLP). Therefore, the current study aimed to examine skeletal and chronological ages in subjects with a UCLP for comparison with those of a non-cleft control group to derive clinical guidelines.

Hand-wrist films of 45 UCLP subjects (24 male, 21 female) and 45 Angle Class I orthodontic patients (17 male, 28 female) were evaluated. Skeletal age was assessed by comparing ossification events with standard radiographs illustrated in the Greulich-Pyle atlas and recording based on the best match of maturity criteria.

A high correlation coefficient was observed between skeletal and chronological ages in the overall study sample (p < 0.01) (N = 90). Skeletal age (11.4 years) was delayed in the UCLP group when compared with chronological age (12.3 years), although the difference between the two was statistically insignificant. Skeletal age (13.6 years) was similar to chronological age in the control group (13.1 years).

The discrepancy between chronological and skeletal age was greater in UCLP subjects compared with controls. Given that the skeletal age of male and female UCLP subjects was delayed in comparison with their chronological ages, it is of particular importance that hand-wrist films should be used instead of chronological age to assess the growth status of UCLP subjects.

The aim of this study was to evaluate the short- and long-term effects of hybrid-Hyrax, Alt-RAMEC and applied, miniscrew reinforced, heavy intermaxillary elastics on a modified lingual arch in growing skeletal Class III patients.

Fifteen subjects (seven male, eight female) were included, with an average age of 12.52 ± 0.94 years, of cervical vertebrae maturation (CVM) stage CS2-CS4 and skeletal Class III malocclusions due to a retrognathic maxilla. Nine weeks of Alt-RAMEC were followed by eight to nine weeks of maxillary protraction with heavy 400 gm Class III elastics worn 24 h/day. Treatment was finalised with orthodontic fixed appliances. Cone beam computed tomographic (CBCT) scans were taken initially (T1), at the end of maxillary protraction (T2) and four years after active orthopaedic treatment (T3). Cephalometric measurements were performed on reconstructed lateral cephalograms and the differences between time intervals were calculated using an analysis of variance (ANOVA).

A positive overjet was achieved in all but one subject. From T1 to T2, A point advanced 3.12 ± 3.42 mm and from T2 to T3 advanced a further 2.21 ± 3.49 mm. Significant initial increases in SNA of 1.05° ± 1.10° (p = 0.004), ANB of 2.71° ± 1.01° (p = 0.00), Wits of 4.49 ± 2.21 mm (p = 0.00) and overjet of 4.90 ± 1.66 mm (p = 0.00) were accomplished and maintained without significant changes in the vertical dimension. Upper and lower incisor inclinations were not affected by the protraction protocol but significantly increased (U1-PP: 8.39° ± 5.59°) between T2 and T3. SNB decreased initially by 1.67° ± 1.34° (p = 0.00) but relapsed due to residual mandibular growth and a counterclockwise rotation of the mandibular plane.

The hybrid-Hyrax Alt-RAMEC combined with miniscrew reinforced heavy Class III elastics resulted in a favourable and stable Class III correction.

The objective of this comparative study was to determine the proportion and distribution of tooth number anomalies in the permanent dentition in a sample of Chinese, Indian and Malay orthodontic patients in Singapore.

The cross-sectional study was carried out using radiographic and clinical data from the National Dental Centre of Singapore. Panoramic radiographs and clinical records of 1080 (Chinese (N = 415), Indian (N = 317) and Malay (N = 348)) orthodontic patients aged 12 to 16 years were examined for evidence of tooth number anomalies. Fisher’s exact test was applied to compare the occurrence of hypodontia and hyperdontia between the ethnicities and genders.

The prevalence of hypodontia in Chinese, Indian and Malay orthodontic patients was 13.7%, 6.0% and 14.4%, respectively. Chinese patients had a significantly higher prevalence of hypodontia compared with Indian patients (OR 2.50, 95% CI 1.29–4.83, p < 0.001). Malay patients had a significantly higher prevalence of hypodontia compared with Indian patients (OR 2.63, 95% CI 1.34–5.17, p < 0.001). The most commonly missing tooth in the Indian patients was the upper lateral incisor (39.0%), whereas that in the Chinese and Malay patients was the lower second premolar (26.1% and 26.2%, respectively).

The prevalence of hyperdontia in Chinese, Indian and Malay patients was 7.0%, 3.8% and 7.8%, respectively. Male patients had a significantly higher prevalence of hyperdontia compared with female patients (OR 1.87, 95% CI 1.14–3.07, p = 0.015). Supernumerary teeth occurred more frequently in the anterior maxilla (34.1%) than in other regions of the jaws. Supernumerary teeth also occurred more frequently in the maxilla (76.9%) than in the mandible (23.1%).

There are significant differences in the presentation of anomalies in tooth number in the permanent dentition of Chinese, Indian and Malay orthodontic patients in Singapore.

This review provides a comprehensive assessment of the benefits of adjunctive orthodontic treatment with or without periodontal regenerative surgery in the treatment of angular bony defects, defect volume, and periodontal tissue conditions in adult patients.

An electronic keyword search was conducted in the literature database PubMed as well as in Google Scholar.

Originally, studies describing all types of orthodontic tooth movement (tipping, bodily movement, intrusion, extrusion) in relation to bone defects such as periodontal, furcation and extraction site defects were reviewed. Only those articles depicting tooth movement after periodontal therapy and the control of inflammation were included.

Evidence indicates that orthodontic tooth movement can result in the reduction or elimination of periodontal bony defect dimensions, a reduction in probing pocket depth and a gain in clinical attachment level. Furthermore, the published data show that orthodontic tooth movement before or after regenerative surgery can provide therapeutic benefits in the recovery of angular bony defects.

This review supports the premise that adjunctive orthodontic treatment in adults with reduced but healthy periodontal tissues is a solution for the modification of bony defect contours with or without periodontal regenerative therapy.

To investigate the applicability of Pont’s index for predicting maxillary and mandibular dental arch widths in a Pakistani population.

A Hirox digital stereomicroscope (SM) (HIROX KH7700 Japan) was used to construct digital models of fabricated plaster casts. Gender differences in the measured totals of the incisor widths, arch widths and expansion indices were evaluated. Pont’s correlations were computed between measured and predicted arch widths. An analysis of variance (ANOVA) was applied to determine the differences between arch length and arch perimeter groups.

Males had significantly larger mean values for the sums of the incisors, arch widths and expansion indices compared with females (p ≤ 0.05). There were significant differences observed between the large and small, average and small and the average and large arch length groups (p ≤ 0.05) in the maxilla, while a significant difference was observed only between the large and small arch length groups in the mandibular arch. Pont’s index predictions were consistently less than the actual interpremolar and intermolar arch widths for both genders. The dissimilarity in the predictions for interpremolar width averaged -4.33 mm for males and -4.21 mm for females while the intermolar width averages were -4.93 mm for males and -4.92 mm for females.

The results indicated that Pont’s index should not be applied to the Pakistani population. Maxillary and mandibular arch length groups and arch perimeters should be carefully investigated before applying any prediction formulae.

To evaluate and compare the skeletal, dentoalveolar and soft tissue effects of two different alternate rapid maxillary expansion (RMEs) and constriction (Alt-RAMEC) procedures.

Thirty-two consecutive patients presenting with a skeletal Class III malocclusion were placed into two comparative groups. Group 1 consisted of 16 patients (5 females and 11 males; mean age: 11.45 ± 1.87 years) who had an Alt-RAMEC procedure for five weeks and Group 2 consisted of 16 patients (6 females and 10 males; mean age: 11.52 ± 1.29 years) who had an Alt-RAMEC procedure for nine weeks. The parents of the patients were instructed to open the screw twice per day for one week and to close it twice per day for the following week (0.20 mm per turn). Nine angular and 20 linear cephalometric variables were measured.

The groups were well matched in relation to patient gender distribution, chronological age and initial cephalometric values. Both Alt-RAMEC procedures showed similar effects with no statistically significant differences. The maxillae moved slightly forward and the mandible moved slightly downward, the changes of which caused an improvement in the maxillo-mandibular relationship in both groups. The overjet slightly increased and the overbite decreased in both groups. The upper lip moved slightly forward during the nine-week treatment Alt-RAMEC group.

Despite the favourable and similar effects of both procedures, neither seems to be sufficient for the complete correction of a skeletal Class III malocclusion.

This case report describes the orthodontic treatment of a 20 year-old female who presented with a severe anterior open bite, increased lower facial height and mandibular asymmetry. The patient was diagnosed with a Class I skeletal pattern but a Class III dental relationship, an anterior and unilateral posterior open bite, a canted posterior occlusal plane, a clockwise rotation and vertical growth pattern of the mandible incorporating a chin deviation to the right.

The aim of treatment was to correct identified adverse oral habits, improve the facial profile and mandibular asymmetry, provide a satisfactory occlusion and restore TMJ health, which could not be guaranteed.

An occlusal splint was used in the first stage of treatment to intrude the posterior teeth, eliminate the occlusal disturbance and control the adverse oral habits. Two micro-implant anchorage devices were placed on the buccal and lingual sides of the left buccal segment to further intrude the left posterior teeth. MEAW technology was used after aligning and levelling the teeth.

Satisfactory overbite, overjet and molar relationships were obtained and the facial profile greatly improved after orthodontic treatment, the outcome of which was stable at 24 months’ review.

Clinical practice encounters the unfortunate consequences of dental trauma. The avulsion of permanent teeth is seen in 0.5–3% of all dental traumatic injuries, and when re-implanted, a tooth can undergo ankylosis in the form of replacement resorption. When ankylosis of a maxillary incisor occurs in a pre-adolescent, the affected tooth gradually becomes infra-occluded with time, which results in severe local dentoalveolar disturbances in normal growth and development, along with aesthetic concerns that challenge orthodontic management. To achieve an ideal dental outcome, an interdisciplinary approach is often required.

To detail a case report of an infra-occluded ankylosed central incisor successfully treated with a single tooth osteotomy and distraction osteogenesis in conjunction with mechanotherapy to correct the osseous and gingival margins.

This combined orthodontic/surgical case report was completed in stages by (1) pre-surgical orthodontics to diverge the roots of the adjacent teeth from the surgical site, (2) a single tooth osteotomy followed by distraction osteogenesis, (3) postsurgery orthodontics, and (4) retention. Consent and complete records were obtained, including pre-treatment photographs, radiographs and cephalometric superimpositions over an eight-year period from initial presentation until retention.

Distraction osteogenesis in combination with orthodontics successfully managed the dentoalveolar and soft tissue defect. If tooth replacement is eventually needed, donor site morbidity associated with conventional bone and soft tissue grafting procedures may be eliminated.

This combined interdisciplinary treatment is an effective alternative to bony and soft tissue augmentation procedures that may not be as predictable in restoring vertical and horizontal osseous and soft tissue defects resulting from severe infraocclusion of anterior teeth.