Thai Journal of Orthodontics

Correction of Severe Skeletal Class II Discrepancy with Orthodontic Treatment Combined with Bimaxillary Orthognathic Surgery: A Case Report

Thanapat Sangwattanarat — 2024-10-11

Background: A 53-year-old Thai female patient came to the orthodontic clinic with upper anterior teeth protrusion and insecurity while smiling as the chief complaints. Her expectation was to correct these problems. The examination showed severe skeletal Class II discrepancy with hyperdivergent facial pattern, orthognathic maxilla but retrognathic mandible, and anterior gummy smile. An orthodontic treatment combined with bimaxillary orthognathic surgery was planned. The treatment objectives were to correct the upper anterior teeth protrusion and gummy smile and improve the patient’s skeletal, dental, and soft tissue morphology. The treatment duration was 34 months to achieve normal skeletal, dental, and soft tissue structure in the anteroposterior, vertical, and transverse dimensions. At 30 months after completing treatment, the patient was recalled. We found acceptable function, improved esthetic results, and stability. The patient was pleased with the treatment outcome.

Orthodontist and Obstructive Sleep Apnea Screening Tools

Tuangporn Jessadapornchai — 2024-10-11

Obstructive sleep apnea (OSA) is a sleep disorder that contributes to disrupted sleep due to a cessation of breathing or a decrease in airflow. OSA is diagnosed by polysomnography (PSG), which is considered to be the gold standard. However, conducting a PSG has limitations that include, time consumption, inconvenience, and cost. Also, all institutions may not have the equipment, technicians, or expert sleep physicians for a definitive diagnosis of OSA. Patients who have subclinical symptoms may go undiagnosed because of its non-specificity and patient unawareness. OSA should be examined in a timely manner. If the disease goes undiagnosed for an extended time, many short- and long-term unsatisfactory outcomes may occur that affect a person’s lifestyle leading to dramatic consequences. Recent literature encourages orthodontists to know how to investigate OSA and the upper airway using questionnaires and radiography as screening tools before undergoing polysomnography.

Obstructive Sleep Apnea Prevalence, Upper Airway Dimensions, and Sleep Parameters in Skeletal Class III Malocclusion Patients Undergoing Orthognathic Surgery with Different Vertical Skeletal Patterns

Thanakorn Kaewja — 2024-10-11

Background: Craniofacial morphology’s relationship with airway dimensions has been extensively studied. Despite this, evidence regarding obstructive sleep apnea (OSA) prevalence and differences in airway dimensions among vertical skeletal patterns in skeletal Class III malocclusion patients undergoing orthognathic surgery is limited. Objective: To determine the prevalence of OSA and compare upper airway dimensions and sleep parameters among skeletal Class III patients with different vertical skeletal patterns. Materials and methods: The study involved 98 adult patients (39 male and 59 female) with skeletal Class III malocclusions undergoing orthognathic surgery. Patients were divided into three groups according to vertical skeletal patterns: high-angle (SN-GoGn > 33°; 47 patients), low-angle (SN-GoGn < 25°; 20 patients), and normal-angle (SN-GoGn 25-33°; 31 patients) groups. OSA prevalence and sleep parameters, including the apnea-hypopnea index and lowest oxygen saturation, were assessed using a portable level III polysomnography device. Cone beam computed tomography was performed, and upper airway dimensions, including nasopharyngeal, oropharyngeal, hypopharyngeal, and total upper airway volumes and minimum cross-sectional area, were measured using Dolphin Imaging software. Group differences were analyzed using ANOVA and post hoc Tukey tests (P < 0.05). Results: The prevalence of OSA among skeletal Class III malocclusion patients was 11 of 98 (11.22 %). Upper airway dimensions and sleep parameters did not differ significantly among vertical skeletal pattern groups. Conclusion: Despite a comparable OSA prevalence in skeletal Class III patients, screening for OSA is crucial in those with Class III malocclusion undergoing mandibular setback surgery, irrespective of vertical patterns.

Comparison of Masticatory Muscle Effort when Chewing on an Anterior Bite Plane Fabricated from Hard and Soft Materials

Passakorn Wasinwasukul — 2024-10-11

Background: Different anterior bite plane materials may affect masticatory muscle effort (ME) differently. ME is defined in this study as the electrical activity used per unit of bite force. Objective: We aimed to compare the effects of a hard acrylic resin anterior bite plane (HARD) and a semi-soft thermoplastic anterior bite plane (SOFT) on ME over a 3-month period in children with deep bites. Materials and methods: Thirty-eight children with deep bites were randomly assigned to either the HARD or SOFT group (n = 19 each). Masseter and anterior temporalis activity along with maximum bite force (MBF) were measured during appliance placement. Anterior and posterior ME were calculated by dividing muscle activity by the anterior and posterior MBF, respectively. Data were collected at baseline (T0), at one month (T1), and at three months (T2). Within- and between-group comparisons were performed (α = 0.05). Results: Neither significant intra-group nor between-group of ME was found throughout the study period (P > 0.05). Conclusion: Neither a hard nor soft anterior bite plane had a disadvantageous effect on ME as none of the ME values exceeded the baseline values during treatment.

Effect of Predrilling Diameter on Orthodontic Miniscrew Primary Stability

Chutimont Teekavanich — 2024-10-11

Background: Predrilling diameter is a factor that is associated with miniscrew primary stability. However, no studies have reported on the relationship between predrilling sizes and shear force loaded as anchorage during orthodontic treatment. Objective: The purpose of this study was to evaluate the effect of 0.70, 0.80, 0.90, 1.00, 1.10, and 1.20 mm predrilling sizes on insertion torque and shear test using 1.30-mm diameter miniscrews in 1-mm thick synthetic cortical bone. Materials and methods: Insertion torque was recorded using a torque driver. The shear test was performed using a universal testing machine by loading a tangential force perpendicularly to the miniscrew at 1 mm/min until it was displaced by 0.50 mm. Results: Overall, the insertion torque tended to significantly decrease as the predrilling diameters increased. The exceptions were in the 0.70 and 0.80 mm groups that had insertion torque values lower than those in the 0.90 mm and 1.00 mm groups. Regarding the shear test, although there were no significant differences among the groups, the 1.20-mm predrilling diameter group demonstrated a much lower value, suggesting that it might be easier to dislodge after receiving an orthodontic force. Conclusion: Predrilling diameter size up to 77 % of the 1.30-mm outer diameter miniscrew can be used to achieve optimal orthodontic miniscrew primary stability.

Factors Influencing Orthodontic Patient Compliance with Removable Retainers

Lalita Jeamkatanyoo — 2024-10-11

Background: Maintaining the results of orthodontic therapy requires adherence to the use of removable retainers. However, compliance-related variables remain debatable. Objective: This study aimed to measure patient compliance in wearing a retainer and explore the factors that affect compliance. Materials and methods: Random sampling was conducted on 1,078 patients who had completed full-fixed appliance therapy from 2019 to 2022. The selected patients were stratified by the number of years (1 to 2, > 2 to 3, and > 3 to 4 years) after debonding. A telephone questionnaire consisted of four parts: patient characteristics, retainer utilization, knowledge, and attitude factors related to compliance. Descriptive statistics and binary logistic regression were used for the analysis. Results: There were 295 patients participating in this study. The response rate was 97 %. The percentage of compliance in wearing retainers for 1 to 2, > 2 to 3, and > 3 to 4 years after debonding were 64.30, 64.70, and 60, respectively. There were 5 factors significantly associated with patient compliance in wearing a removable retainer. Patients with scores of 8-10 in self-assessment of compliance had significantly more compliance than patients with scores of 0-7 (odds ratio = 20.40, 95 % CI 10.25-40.61). Conclusion: The percentage of compliance in wearing a retainer during four years after debonding was 63.10. Factors significantly associated with compliance in wearing a retainer were age, number of recall visits, loss of retainer, self-assessed level of compliance in wearing a retainer, and knowledge of the frequency of wearing a retainer.