Obstructive sleep apnea: a follow-up program in its relation to temporomandibular joint disorder, sleep bruxism and orofacial pain.

OBJECTIVE: To evaluate the correlation between obstructive sleep apnea (OSA) and temporomandibular joint (TMJ) morphology, tooth wear condition, orofacial pain through a follow-up program. MATERIALS AND METHODS: Seventy one OSA patients were divided into three groups according to their (apnea hypopnea index) AHI: mild group (n = 23), moderate group (n = 24), and severe group (n = 24). All patients had OSA therapies around six months after confirm the diagnosis of OSA. The tooth wear score and orofacial pain condition of all patients were recorded via clinical examination. Cone beam computed tomography (CBCT) images were also taken when confirm the diagnosis of OSA (T0), 6 months after the diagnosis (T1), and 6 months after the OSA treatment (T2). Parameters indicating the condylar morphology and joint space were evaluated. The differences of clinical symptoms and TMJ conditions among T0, T1 and T2 time point were detected in the three groups respectively. The changes in T1-T0 and T2-T1 of all descriptions among three groups were also compared. The correlations between AHI and clinical symptoms were detected with Spearman correlation analysis. RESULTS: In mild group, there was no difference in all clinical symptoms and TMJ morphology among the three time points. Both in moderate and severe group, the condylar volume, superficial area, wear score, visual analogue scales (VAS), and R value (indicating condyle position) displayed significant differences among the three time points (P < 0.05). From T0 to T1, mild group displayed fewer decreases in the condylar volume and superficial area and fewer increases in wear score than that in moderate and severe group (P < 0.05). From T1 to T2, there was a greatest reduction in severe group for R value, and significant difference in the description of VAS and R value were found among the three groups. AHI was negatively correlated condylar volume and condylar superficial area, and was positively correlated with tooth wear score and VAS (P < 0.05). CONCLUSION: Moderate to severe OSA will aggravate orofacial pain and tooth wear, affect TMJ volume and superficial area, even change the location of condyles. Appropriate OSA therapies may be effective ways to alleviate these adverse effects in long-term.

Treatment effects after maxillary expansion using tooth-borne vs tissue-borne miniscrew-assisted rapid palatal expansion appliance.

INTRODUCTION: The study investigated the skeletal effects and root resorption in young adults with maxillary transverse deficiency after tissue-borne or tooth-borne mini-implant anchorage maxillary expansion. METHODS: Ninety-one young adults with maxillary transverse deficiency, aged 16-25 years, were divided into 3 groups according to the treatment method: group A (n = 29) comprising patients treated with tissue-borne miniscrew-assisted rapid palatal expansion (MARPE), the group B (n = 32) comprising patients treated with tooth-borne MARPE, and the control group (n = 30) comprising patients only treated with fixed orthodontic therapies. Pretreatment and posttreatment cone-beam computed tomography images were used to assess the change of maxillary width, nasal width, first molar torque and root volume by paired t test in the 3 groups, respectively. Analysis of variance and Tukey least significant difference analysis were used to detect the changes of all descriptions among the 3 groups P <0.05. RESULTS: In the 2 experimental groups, we observed significant increases in the width of the maxilla, nasal, and arch width, as well as the molar torque. In addition, the height of the alveolar bone and the root volume decreased significantly. There were no significant differences in the maxilla, nasal, and arch width change between the 2 groups. Group B displayed more increases in buccal tipping, alveolar bone loss, and root volume loss than group A (P <0.05). Compared with groups A and B, the control group showed negligible tooth volume loss, with no expansion effect in both skeletal and dental descriptions. CONCLUSIONS: Tissue-borne MARPE produced the same expansion efficiency as tooth-borne MARPE. However, tooth-borne MARPE causes more dentoalveolar side effects in buccal tipping, root resorption and alveolar bone loss.

Evaluation of root resorption in the lower incisors after orthodontic treatment of skeletal Class III malocclusion by three-dimensional volumetric measurement with cone-beam computed tomography.

OBJECTIVES: To investigate the volumetric changes of the lower incisor roots in skeletal Class III orthodontic patients with anterior crossbite after premolar extraction therapy. MATERIALS AND METHODS: Thirty-six adults, aged 18-28 years, had four-premolar extraction treatment. Pre- and posttreatment cone-beam computed tomography (CBCT) images were used to assess the thickness and height of alveolar bone, root volume, and length. A paired t-test was used to detect changes in root volume and length before and after treatment. Pearson's correlation analysis was applied to estimate the correlation between root volume and dentoskeletal morphology. RESULTS: Both the central and lateral incisors had intrusion and tipping movement after treatment. Compared with pretreatment data, root length decreased significantly. The lingual root volume of root cervical, apical third, and the labial root volume of the root apical third decreased significantly (P < .05), among which the percentage of tooth loss at the tip volume was the highest. The pretreatment height of the alveolar ridge crest, thickness of the alveolar bone, and type of incisor movement were related to the volume and length loss. CONCLUSIONS: Volume and length loss in the apical third of the lower incisor roots in skeletal Class III patients treated with a Class III bicuspid extraction pattern is common. The pretreatment height of the alveolar ridge crest, thickness of the alveolar bone, and type of tooth movement are related to the loss.

Effects of occlusal splint and exercise therapy, respectively, for the painful temporomandibular disorder in patients seeking for orthodontic treatment: a retrospective study.

OBJECTIVE: To evaluate the effect of hard stabilization splints (HSS), counselling and exercise therapies, respectively, for the painful temporomandibular disorder (TMD) in patients seeking for orthodontic treatment through magnetic resonance imaging (MRI) and clinical examination. MATERIALS AND METHODS: Eighty-seven TMD patients were divided into two groups according to their therapies: the HSS group (n = 43) comprising of patients treated with HSS, counselling and masticatory muscle exercises; the control group (n = 44) comprising of patients treated with counselling and masticatory muscle exercises alone. All patients had orthodontic therapies after the first treatment phase. The joint pain and clicking of all patients were recorded via clinical examination. MRIs of HSS groups were taken before (T0), after the first phase (T1), and after the orthodontic treatment (T2). Parameters indicating the condyles and articular discs were evaluated. Clinical symptom (pain and clicking) changes among T0, T1 and T2 time point were detected in the two groups respectively. The significant differences between HSS and control groups, as well as between male and female were tested at T1 and T2. Position changes of condyles and discs in HSS group among T0, T1 and T2 were detected in male and female respectively. RESULTS: After the first treatment phase, there was no difference in the decrease of facial pain between the two group, as well as between male and female in the two groups (P > 0.05). Clicking decreasing was not statistically significant. After the whole orthodontic periods, the TMJ pain relapsed in female of the control group, and the number of female's pain joints was more than male's (P < 0.05). In the HSS group, the posterosuperior movements of discs and the anteroposterior movements of condyles were recorded in closing position (P < 0.05). After the whole orthodontic periods, female's disc-condyle angles increased, the discs to HRP distance decreased and condyles to VRP distance increased when compared with the data of T1 (P < 0.05). CONCLUSIONS: For the orthodontic patients with painful TMD, HSS combined with counselling and exercise therapies before orthodontic treatment could provide pain relief. HSS is helpful to improve the position and relation of discs and condyles. In addition, male's prognosis is better than female's in terms of stability.

Effect of premolar extraction on upper airway volume and hyoid position in hyperdivergent adults with different mandibular length.

INTRODUCTION: The objective of this study was to investigate the morphological changes of the upper airway and the position of the hyoid bone in hyperdivergent adults with different mandibular lengths after premolar extraction. MATERIALS: The data of 57 hyperdivergent adults, aged 20-35 years, who had 4 premolar extractions were included for the study. Mandibular length (CoGn) was used for grouping (A: long CoGn, B: short CoGn). Pretreatment and posttreatment lateral cephalograms and cone-beam computed tomography images were used to assess the position of mandible, hyoid bone, and upper airway using paired t test. An independent sample t test was used to detect changes of the airway and hyoid position between groups A and B. Pearson correlation analysis was applied to estimate the correlation between pharyngeal spaces and dentoskeletal morphology at P <0.05. RESULTS: In all subjects, we observed retraction of the upper incisors, mesial movement of the lower molars, and reduction of the mandibular planes. In group A, differences were found in anterior and posterior movements of the hyoid bone, increase of airway volume, minimum cross-sectional area (MCA) and anteroposterior linear distance (APL) (P <0.05). There were notable differences in the change of hyoid position, airway volume, MCA, and APL between group A and group B. Glossopharyngeal and hypopharyngeal volumes, MCA, and APL were correlated with articular angle, mandibular plane, and hyoid bone position (P <0.05). CONCLUSIONS: With a comprehensive diagnosis and treatment, premolar extraction in hyperdivergent adults with favorable CoGn can facilitate improvement of esthetics, hyoid bone position, and the increase in glossopharyngeal and hypopharyngeal volumes and MCA.

Maxillary width and hard palate thickness in men and women with different vertical and sagittal skeletal patterns.

INTRODUCTION: The objective of this research was to compare maxillary width and hard palate thickness in men and women with different vertical and sagittal skeletal patterns. METHODS: A total of 241 adults (93 men and 148 women aged from 18 to 25 years) were divided into male and female groups. Subjects were then separately divided into 3 sagittal skeletal groups and 3 vertical skeletal groups. A lateral cephalogram and a cone-beam computed tomography were taken for each subject. We measured the parameters to make statistical analyses and compared them between the different groups. RESULTS: Women had smaller craniomaxillofacial bone width and palatal thickness than men. In sagittal groups, maxillary width, maxillary alveolar width, and external temporomandibular joint fossa width in Class II and Class III malocclusion groups were smaller than in the Class I group for both women and men. The internal temporomandibular joint fossa width was the same results in men and women. In vertical groups, palate thickness, maxillary width, and maxillary alveolar width of the high-angle group were smaller than those of the low-angle group, regardless of sex. CONCLUSIONS: To an extent, maxillary width is correlated with vertical and sagittal skeletal patterns, and insufficient maxillary width would lead to unfavorable skeletal patterns. Differences exist in the morphology of craniomaxillofacial bone between men and women. Therefore, these findings can provide clinicians with references for differential diagnosis and treatment plans.