Accuracy and reliability of the expected root position setup on clinical decision making of root position at midtreatment.

INTRODUCTION: Accurate root position is imperative for successful orthodontic treatment that is stable and functional. Current methods to monitor root position are either inaccurate or use relatively high levels of radiation. A method to generate an expected root position (ERP) setup has been reported to have the potential to accurately evaluate root position with minimal radiation. The purpose of this study was to determine the accuracy and reliability of the clinical decisions made on root position using the ERP setup. METHODS: This retrospective study included 10 subjects who had pretreatment and midtreatment cone-beam computed tomography (CBCT) scans and study models. An ERP setup was generated for all patients at midtreatment. Four examiners assessed both the CBCT scan and ERP setup and made clinical decisions regarding the root position with each method. Cohen's kappa was determined to assess intraoperator and intermethod reliability. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated to determine the accuracy of the ERP setup. RESULTS: The kappa values for intraoperator reliability for both the CBCT scan and ERP setup fell within the 0.61-0.80 range. The kappa values for intermethod reliability between the CBCT scan and ERP setup fell within the 0.61-0.80 range for all tooth groups. The sensitivity of the ERP setup ranged from 0.72 to 0.90, specificity ranged from 0.89 to 0.97, positive predictive value ranged from 0.57 to 0.85, and negative predictive value ranged from 0.93 to 0.99. CONCLUSIONS: This study demonstrated that the ERP setup, when compared with the gold standard CBCT scan, was accurate and reliable in making clinical decisions regarding root position at midtreatment.

Short-term cone-beam computed tomography evaluation of maxillary third molar changes after total arch distalization in adolescents.

INTRODUCTION: Our objectives were to evaluate changes in the position of maxillary third molars with cone-beam computed tomography images in adolescents after total arch distalization using a modified C-palatal plate (MCPP) and to compare them with the changes in a matched control group. METHODS: We included 68 maxillary third molars of 40 adolescent patients (mean age, 12.6 years). They were divided into MCPP and control groups. Cone-beam computed tomography images were taken before and after molar distalization (mean duration, 14.4 months) in the MCPP group and also in the control group (mean duration, 12.9 months). The changes in the position, angulation, and rotation of the third molars were assessed, and the volumes of maxillary tuberosity were measured. RESULTS: After distalization, the third molars moved backward (1.2 mm) and upward (0.5 mm) in the MCPP group with a significant difference (P <0.003), and they moved downward and forward in the control group. The changes in rotation and angulation were insignificant. The volumes of maxillary tuberosity increased in both groups. CONCLUSIONS: Maxillary total arch distalization caused unerupted third molars to move backward and upward, with an insignificant difference in the posttreatment volume of maxillary tuberosity. Therefore, it may be possible to perform maxillary total arch distalization in adolescents with unerupted third molars without a germectomy, at least in the short term.

Accuracy and reliability of the expected root position setup methodology to evaluate root position during orthodontic treatment.

INTRODUCTION: Current methods to evaluate root position either are inaccurate (panoramic radiograph) or expose patients to relatively large amounts of radiation (cone-beam computed tomography [CBCT]). A method to evaluate root position by generating an expected root position (ERP) setup was recently reported but has not been validated. The purpose of this study was to quantitatively assess the accuracy and reliability of the ERP setup with adequate statistical power. METHODS: This retrospective study included 15 subjects who had completed phase 2 orthodontic treatment. An ERP setup was generated for all patients after treatment. The ERP setup was compared with the posttreatment CBCT scan, which served as the control. The mesiodistal angulation and buccolingual inclination of all teeth in both the ERP setup and the posttreatment CBCT scan were measured and compared. Bland-Altman analysis was used to assess interoperator reliability, intraoperator reliability, and agreement between the ERP setup and the posttreatment CBCT scan. RESULTS: Bland-Altman plots showed high interoperator and intraoperator reliabilities. These plots also showed strong agreement between the ERP setup and the posttreatment CBCT scan; 11.8% of teeth measured for mesiodistal angulation and 9.6% of teeth measured for buccolingual inclination were outside the ±2.5° range of clinical acceptability. CONCLUSIONS: We validated that the method to generate an ERP setup to evaluate root position for posttreatment orthodontic assessment is accurate and reliable.

Comparison of treatment effects between four premolar extraction and total arch distalization using the modified C-palatal plate.

OBJECTIVE: The purpose of this study was to compare the skeletal, dental, and soft-tissue treatment effects of nonextraction therapy using the modified C-palatal plate (MCPP) to those of premolar extraction (PE) treatment in adult patients with Class II malocclusion. METHODS: Pretreatment and posttreatment lateral cephalographs of 40 adult patients with Class II malocclusion were retrospectively analyzed. The MCPP group comprised 20 patients treated with total arch distalization of the maxillary arch while the PE group comprised 20 patients treated with four PE. Fifty-eight linear and angular measurements were analyzed to assess the changes before and after treatment. Descriptive statistics, paired t-test, and multivariate analysis of variance were performed to evaluate the treatment effects within and between the two groups. RESULTS: The MCPP group presented 3.4 mm of retraction, 1.0 mm of extrusion, and 7.3° lingual inclination of the maxillary central incisor. In comparison, the PE group displayed greater amount of maxillary central incisor retraction and retroclination, mandibular incisor retraction, and upper lip retraction (5.3 mm, 14.8°, 5.1 mm, and 2.0 mm, respectively; p < 0.001 for all). In addition, the MCPP group showed 4.0 mm of distalization and 1.3 mm of intrusion with 2.9° distal tipping of the maxillary first molars. CONCLUSIONS: These findings suggest the MCPP is an effective distalization appliance in the maxillary arch. The amount of incisor retraction, however, was significantly higher in the PE group. Therefore, four PE may be recommended when greater improvement of incisor position and soft-tissue profile is required.

Three-dimensional evaluation of root position at the reset appointment without radiographs: a proof-of-concept study.

BACKGROUND: Accurate root position is integral for successful orthodontic treatment. Current methods of monitoring root position are either inaccurate, exhibit poor resolution, or use relatively large amount of radiation relative to the benefits for the patient. The purpose of this study was to present an approach that can monitor root position during orthodontic treatment with minimal radiation. METHODS: Cone-beam computed tomography (CBCT) scans were taken for a patient at pre-treatment and at a dedicated reset appointment. An extra-oral laser scan of a poured up cast was taken at the reset appointment. An expected root position (ERP) setup, an approximation of the root position at the reset appointment, was generated using the pre-treatment CBCT scan and reset appointment cast. The ERP setup was compared to the CBCT scan taken at the reset appointment which served as the control. Color displacement maps were generated to measure any differences between the expected and true root positions. RESULTS: Color map displacement analysis after indirect superimposition found displacement differences of 0.021 mm ± 0.396 mm for the maxillary roots and 0.079 mm ± 0.499 mm for the mandibular roots. CONCLUSIONS: This approach was demonstrated in a patient at the reset appointment to have the potential to accurately monitor root positions during treatment in three dimensions without the need for additional radiographs.