Orthodontic Waves最新文献

Purpose

To evaluate the literature on the stability of open bite treatment using extraction or non-extraction methods.

Methods

Medline, Scopus, and Cochrane library were electronically searched until December 2017. Studies were considered for evaluation if they reported overbite measurements pre-treatment, post-treatment, and at least 1-year post-retention for non-surgical orthodontic patients with permanent dentition, treated by extraction or non-extraction methods The risk of bias of the selected articles was assessed.

Results

The search retrieved 985 articles, only 6 articles were included after applying the selection criteria. Two articles were case-control studies, and the other four were case series studies. The mean stability rates were 93.53% and 73.68% in extraction and non-extraction cases, respectively. Because each included study presented data of either the extraction or non-extraction method, it was not possible to perform a meta-analysis by pooling the results of the studies to compare the two methods. However, meta-analysis was conducted to compare the overbite between post-treatment and post-retention within each method. The results showed no significant change in extraction cases (mean difference (MD) 0.49, 95% CI −0.18–1.16; P = 0.15), but showed a significant change in non-extraction cases (MD 1.12, 95% CI 0.77–1.46; P < 0.00001).

Conclusions

Our findings indicated no significant relapse in extraction cases, but a significant relapse in non-extraction cases. However, due to no direct comparison, the optimum treatment method for open bite patients with permanent dentition remains questionable. Further studies with a high level of evidence that compare both treatment methods are needed to draw a definitive conclusion.

Purpose

To evaluate and compare the long term stability of treatment outcome in patients treated with fixed orthodontic treatment with and without premolar extractions.

Material and methods

Fifty five debonded patients (35 females and 20 males) with complete pre-treatment (T0) and post-treatment (T1) records with at least 3 years of post-retention (T2) were included in the study. These patients were divided into two groups; Extraction group comprising of 30 patients who had undergone 4 premolar extractions and non-extraction group had 25 patients. Long term stability of post-treatment occlusion was assessed with Little’s irregularity index, intercanine width and ABO model grading system.

Results

The incisor irregularity score increased in both extraction and non-extraction groups from post-treatment (T1) to post-retention (T2) and the mean changes were statistically significant. The results of Mann–Whitney test for Little’s irregularity index and intercanine width showed no statistically significant differences between the extraction and the non-extraction groups at T1 to T2. The overall mean changes in the ABO variables showed no statistically significant differences (P > 0.05) from post-treatment (T1) to post-retention phase (T2) in extraction and non-extraction groups except interproximal contacts, which showed a statistically significant difference.

Conclusion

There was significant relapse in the alignment of maxillary and mandibular anterior teeth with a change in Little’s irregularity score, intercanine width and ABO scores from post-treatment to post-retention. The comparison of relapse in extraction and non-extraction groups did not show significant differences from T1 to T2. Therefore, similar relapse may be expected irrespective of treatment plan.

Objective

The purpose of this study was (a) to establish hard tissue cephalometric norms for the population of Himachali Mongoloid tribes, (b) to study the sexual dimorphism in hard tissue cephalometric norms of this population and (c) to compare the Himachali Mongoloid norms with the norms established by Downs.

Material and method

Sixty Himachali Mongoloid subjects were selected on the basis of Angle’s Class I molar relationship, well aligned arches, full complement of teeth, having clinically acceptable facial esthetics, no previous history of Orthodontic treatment, subjects native of the tribal belt of Himachal Pradesh. Lateral head films were traced and Downs cephalometric parameters were recorded. Statistical analysis was done to compare the difference between the established norm and the norm established by Downs for the Caucasian population.

Result

Significant difference was seen in the Angle of convexity, with Himachali Mongoloid tribe population having a more forwardly positioned middle part of the face. This population had less steeper cant of occlusal plane, more acute interincisal angle, more inclined lower incisors in relation to the mandibular and the occlusal plane and more forwardly positioned maxillary incisor in relation to the A-pog line.

Conclusion

These findings suggested that ethnic differences in the facial traits exist and awareness of dentofacial pattern of each ethnic group will ensure better success of the treatment in establishing optimal facial harmony.

This case report describes the orthodontic treatment of a 29-year-old male who lost the maxillary bilateral central incisors as a result of a traffic accident. After emergency treatment for facial fracture by a plastic surgeon, the patient visited our orthodontic clinic. He had a concave profile, Class I molar relationship with slight maxillary retrusion, and crossbite of the maxillary bilateral lateral incisors. The interdental space was insufficient for prosthetic treatment of the missing maxillary incisors. Therefore, we planned to distalize the maxillary and mandibular molars to obtain appropriate interdental space for the prosthetic treatment of the missing teeth and to correct the crowding of the mandibular anterior teeth. The anterior crossbite was corrected, and appropriate overjet and overbite were obtained with functional occlusion after prosthetic treatment. This case report shows that the favorable occlusion and facial profile are obtained by the interdisciplinary treatment and discusses the specific problems which seen after the traffic accident.

Purpose

The purpose of this study is to determine variations in cortical bone heights and thickness of the hard palate for placing orthodontic mini screws. Additionally it was evaluated whether there are any significant variations between males and females, adolescents and adults, right and left sides of the hard palate in the study population.

Materials and methods

CBCT images of 50 patients were retrospectively analysed. Patients were divided into sub-groups: 25 males and females, 24 adolescents (age range 10–19 years) and 26 adults (age range 20–27 years). Hard palate heights and thicknesses were analysed from the incisive fossa to the inter-embrasure region between the 1st and 2nd molars were analysed.

Results

The data revealed that the overall greatest thickness was at the canine-1st premolar embrasure region and the greatest height at the inter-premolar embrasure region. Males showed greater cortical thickness in almost all areas of the palate with significantly greater values in the inter-premolar region. Adolescents showed greater palatal heights than adults in almost all areas with significantly greater values in the inter-molar embrasures. The mid palatal regions showed significantly greater palatal heights in all subgroups.

Conclusion

Orthodontic Mini screws can be optimally placed in the anterior regions of the hard palate for all the groups studied. Males and adolescents showed greater cortical heights as compared to the female and adult population studied.

Purpose

The purpose of the present study was to examine the three-dimensional (3D) lip morphology in cases of skeletal Class I malocclusion with labial inclination of the upper central incisors.

Materials and methods

Thirty-five Japanese patients with malocclusion were divided into 2 groups: 20 patients (Test group; 9 males and 11 females; 7 years 5 months–14 years 2 months) who exhibited Class I malocclusion with labial inclination of the upper central incisors and 15 patients (Control group; 7 males and 8 females; 8 years 0 month–14 years 4 months) who exhibited skeletal Class I malocclusion with standard inclination of the upper central incisors. The 3D morphology of the facial soft tissue was recorded using a 3D surface-imaging device for both groups. The differences in the lip morphology variables between the Test and Control groups were then analyzed statistically.

Results

The central, right and left upper lip inclination angle in the lateral and three-quarter views in the Test group were significantly larger than those in the Control group. The upper lip base area, protrusion surface area, protrusion volume, and protrusion depth were significantly increased compared with the Control group, as were also the lower lip protrusion volume and depth. However, no significant differences in the lower lip base area and surface area were determined between the Test and Control groups.

Conclusions

The upper lip wholly showed labial inclination and forward protrusion in Class I malocclusion with labial inclination of the upper central incisors.

Purpose

To assess buccal cortical bone thickness of the alveolar process in the maxilla and mandible in subjects with different skeletal relationship as an aid in orthodontic miniscrew placement.

Materials and methods

The study was carried out using cone-beam computed tomography (CBCT) images of 94 adult subjects with skeletal Class I, II or III sagittal relationship and normal mandibular plane angle. Buccal cortical bone thickness was obtained at the alveolar processes from canine to second molar at 2 different vertical levels (6, and 8 mm) from the cementoenamel junction (CEJ). Analysis of variance (ANOVA) was used to analyse differences in cortical bone thickness.

Results

The difference in mean values of buccal Cortical thickness was significant between the three skeletal classes in both arches and all sites except for the site between first and second mandibular molars (P < 0.05). In the mandible, buccal cortical plate was thickest between first and second molar in all skeletal classes. In the maxilla, the highest cortical bone thickness for Class I subjects was between first and second molar, for Class II subjects was between canine and first premolar, and for Class III subjects was between first and second premolar. Mandibular measurements increase apically and posteriorly in all skeletal classes.

Conclusions

Buccal cortical bone thickness could be influenced by skeletal relationship. The mandible shows a similar pattern for all skeletal classes. In the maxilla each skeletal relationship shows a different pattern. Skeletal relationship need to be considered in site choice for miniscrew placement.

This is a case report of comprehensive treatment describing the management of an adult patient with bilateral cleft lip and palate who showed severe maxillary transverse deficiency caused by bilateral alveolar clefts. Since the residual alveolar clefts were extremely wide, we performed bone graft into the alveolar clefts first and then expanded the asymmetrically narrowed maxilla by asymmetric transverse distraction osteogenesis, in which an incision for osteotomy was made at the repaired bone bridge. The treatment accomplished successful reconstruction of the dental arches and occlusion. Aesthetic improvement was noted, with no discernible post-treatment relapse of occlusion after two years’ retention.

Purpose

The purpose of this study was to assess hyoid bone position related to gender and aging using lateral cephalometric radiographs in 22 to 84 years old patient.

Materials and methods

Lateral cephalometric radiographs of 459 patients were reviewed retrospectively. The position of the hyoid bone was assessed in terms of horizontal position, rotation, and vertical position. Data were compared between age groups for both genders. Two-factor analysis of variance and Tukey’s honest significant difference (Tukey’s HSD) test were performed.

Results

Mean vertical distance in the 22–29-year age group and the 60–84-year age group was 0.2 mm and 9.7 mm, respectively, among males, and −4.3 mm and −0.3 mm, respectively, among females. There was a trend toward larger measurements in the vertical position in older males (P < 0.001). Among males, all measurements tended to increase significantly with age (P < 0.001). In the over 60-year age group, the posterior position and rotation of the hyoid bone were almost the same for males and females.

Conclusion

Age-related changes in hyoid bone position may decrease swallowing safety. Oral frailty, an early sign of orofacial muscle weakness and functional deterioration, negatively influences dental treatment and swallowing. The hyoid bone shifted to a posterior, rotated, and lower position with increasing age. Especially among males in the over 60-year age group, the hyoid bone had shifted significantly to a lower position. We should focus into the hyoid bone position in lateral cephalometric radiograph.