Quantitative evaluation of palatal bone thickness in patients with normal and open vertical skeletal configurations using cone-beam computed tomography

PURPOSE: To perform a comparative analysis of the palatal bone thickness in Thai patients exhibiting class I malocclusion according to whether they exhibited a normal or open vertical skeletal configuration using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Thirty CBCT images of Thai orthodontic patients (15–30 years of age) exhibiting class I malocclusion with a normal or open vertical skeletal configuration were selected. Palatal bone thickness was measured in a 3.0-mm grid pattern on both the right and left sides. The palatal bone thickness of the normal-bite and open-bite groups was compared using the independent t-test. The level of significance was established at P < .05. RESULTS: The palatal bone thickness in the normal-bite group ranged from 2.2±1.0 mm to 12.6±4.1 mm. The palatal bone thickness in the open-bite group ranged from 1.9±1.1 mm to 13.2±2.3 mm. The palatal bone thickness was lower at almost all sites in patients with open bite than in those with normal bite. Significant differences were found at almost all anteroposterior sites along the 3 most medial sections (3.0, 6.0, and 9.0 mm lateral to the midsagittal plane) (P < .05). CONCLUSION: Class I malocclusion with open vertical skeletal configuration may affect palatal bone thickness, so the placement of temporary anchorage devices or miniscrew implants in the palatal area in such patients should be performed with caution.

Comparison of 2 root surface area measurement methods: 3-dimensional laser scanning and cone-beam computed tomography

PURPOSE: The aim of this study was to compare the use of 3-dimensional (3D) laser scanning and cone-beam computed tomography (CBCT) as methods of root surface measurement. MATERIALS AND METHODS: Thirty teeth (15 maxillary first premolars and 15 mandibular first premolars) from 8 patients who required extractions for orthodontic treatment were selected. Before extraction, pre-treatment CBCT images of all the patients were recorded. First, a CBCT image was imported into simulation software (Mimics version 15.01; Materialise, Leuven, Belgium) and the root surface area of each tooth was calculated using 3-Matic (version 7.01, Materialise, Leuven, Belgium). After extraction, all the teeth were scanned and the root surface area of each extracted tooth was calculated. The root surface areas calculated using these 2 measurement methods were analyzed using the paired t-test (P<.05). Correlations between the 2 methods were determined by calculating the Pearson correlation coefficient. The intraclass correlation coefficient (ICC) was used to assess intraobserver reliability. RESULTS: The root surface area measurements (230.11±41.97 mm²) obtained using CBCT were slightly greater than those (229.31±42.46 mm²) obtained using 3D laser scanning, but not significantly (P=.425). A high Pearson correlation coefficient was found between the CBCT and the 3D laser scanner measurements. The intraobserver ICC was 1.000 for 3D laser scanning and 0.990 for CBCT. CONCLUSION: This study presents a novel CBCT approach for measuring the root surface area; this technique can be used for estimating the root surface area of non-extracted teeth.

Distances from the root apices of posterior teeth to the maxillary sinus and mandibular canal in patients with skeletal open bite: A cone-beam computed tomography study

PURPOSE: This study determined and compared the distances from the maxillary root apices of posterior teeth to the floor of the maxillary sinus, or maxillary sinus distances (MSDs), and the distances from the mandibular root apices of the posterior teeth to the mandibular canal, or mandibular canal distances (MCDs), in Thai subjects with skeletal open bite and skeletal normal bite. MATERIALS AND METHODS: Pretreatment cone-beam computed tomography (CBCT) images were obtained from 30 Thai orthodontic patients (15 patients with skeletal normal bite and 15 with skeletal open bite) whose ages ranged from 14 to 28 years. The CBCT images of the patients were processed and measured using the Romexis Viewer program. The MSDs and MCDs from the root apices of the maxillary and mandibular second premolar, first molar, and second molar to the maxillary sinus floor or the mandibular canal were measured perpendicularly to the occlusal plane. The Student t test was used for comparisons between the 2 groups. RESULTS: The greatest mean MSDs were from the root apex of the second premolars in both groups, whereas the least mean MSDs were from the mesiobuccal root apex of the second molars. The greatest mean MCDs were from the mesial root apex of the first molars, whereas the least mean MCDs were from the distal root apex of the second molars. CONCLUSION: There were no differences in the mean MSDs or the mean MCDs between the skeletal normal bite group and the skeletal open bite group.

Root surface areas of maxillary permanent teeth in anterior normal overbite and anterior open bite assessed using cone-beam computed tomography

PURPOSE: The aim of this study was to compare the root surface areas of the maxillary permanent teeth in Thai patients exhibiting anterior normal overbite and in those exhibiting anterior open bite, using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT images of maxillary permanent teeth from 15 patients with anterior normal overbite and 18 patients with anterior open bite were selected. Three-dimensional tooth models were constructed using Mimics Research version 17.0. The cementoenamel junction was marked manually. The root surface area was calculated automatically by 3-Matic Research version 9.0. The root surface areas of each tooth type from both types of bite were compared using the independent t-test (P < .05). The intraclass correlation coefficient was used to assess intraobserver reliability. RESULTS: The mean root surface areas of the maxillary central and lateral incisors in individuals with anterior open bite were significantly less than those in those with normal bite. The mean root surface area of the maxillary second premolar in individuals with anterior open bite was significantly greater than in those with normal bite. CONCLUSION: Anterior open-bite malocclusion might affect the root surface area, so orthodontic force magnitudes should be carefully determined.

Comparison of interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns using cone-beam computed tomography

PURPOSE: This study evaluated and compared interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns, using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Pretreatment CBCT images of 24 Thai orthodontic patients with Class I and Class II skeletal patterns were included in the study. Three measurements were chosen for investigation: the mesiodistal distance between the roots, the width of the buccolingual alveolar process, and buccal cortical bone thickness. All distances were recorded at five different levels from the cementoenamel junction (CEJ). Descriptive statistical analysis and t-tests were performed, with the significance level for all tests set at p<0.05. RESULTS: Patients with a Class II skeletal pattern showed significantly greater maxillary mesiodistal distances (between the first and second premolars) and widths of the buccolingual alveolar process (between the first and second molars) than Class I skeletal pattern patients at 10 mm above the CEJ. The maxillary buccal cortical bone thicknesses between the second premolar and first molar at 8 mm above the CEJ in Class II patients were likewise significantly greater than in Class I patients. Patients with a Class I skeletal pattern showed significantly wider mandibular buccolingual alveolar processes than did Class II patients (between the first and second molars) at 4, 6, and 8 mm below the CEJ. CONCLUSION: In both the maxilla and mandible, the mesiodistal distances, the width of the buccolingual alveolar process, and buccal cortical bone thickness tended to increase from the CEJ to the apex in both Class I and Class II skeletal patterns.

Molar Intrusion for Treating Anterior Open Bite: A Review of the Literature

Molar intrusion is an option for treating skeletal open configuration cases. Molar intrusion causes counter-clockwise mandibular rotation and anterior open bite closure. Many techniques have been used to intrude maxillary and mandibular teeth by various mechanisms, such as passive posterior bite-blocks, active vertical correctors, functional appliances, and multi-loop edgewise arch wire techniques. Anchorage systems have included high-pull head gear, and recently, miniscrew implants. This article aimed to review all those non-surgical techniques and their mechanisms for molar intrusion.

Raised Chondroitin Sulphate (WF6 Epitope) Levels around Maxillary Molars and Miniscrew Implants during Orthodontic Molar Intrusion

This study aimed to monitor chondroitin sulphate (CS; WF6 epitope) levels in crevicular fluid around maxillary molars and miniscrew implants during orthodontic molar intrusion.              One miniscrew implant was placed in the midpalatal area of each of ten patients with open skeletal configurations, who required orthodontic molar intrusion, and two Sentalloy® closed-coil springs (100 g) were used for molar intrusion.  Gingival crevicular fluid (GCF) around experimental and control molars, and peri-miniscrew implant crevicular fluid (PMICF) were collected before and during load application. Competitive ELISA with monoclonal antibody WF6 and colorimetric protein assay were used to detect CS (WF6 epitope), and total protein concentration, respectively.The results showed that the median CS (WF6 epitope) levels around experimental molars during the loaded period (12 weeks) (2.099 ng/µg of total protein) and those during each two-week interval of the loaded period (1.952, 1.854, 2.604, 2.414, 1.844, 1.44 ng/ µg of total protein respectively) were significantly greater than those during the unloaded period (2 weeks) (0.832 ng/ µg of total protein) (P