Degree and pattern of expansion of commercially available and custom-fabricated miniscrew-assisted rapid palatal expansion systems in young adult patients: A retrospective comparative analysis.

BACKGROUND: Miniscrew-assisted rapid palatal expansion (MARPE) has emerged as a noteworthy non-surgical method for treating maxillary transverse deficiency, especially in young adult patients. Studies have shown that MARPE can achieve significant dentoalveolar and skeletal expansion with long-term stability. The primary objective of this study was to assess the skeletal changes in the maxillary transverse dimension, and the secondary objective was to evaluate the dentoalveolar changes, following the use of a commercially available maxillary skeletal expander (MSE) in comparison to a custom-fabricated MARPE. METHODS: This retrospective study involved 50 young adult patients diagnosed with skeletal transverse maxillary deficiency, divided into two groups (MSE and custom MARPE), with 25 patients in each group. Pre- and post-expansion cone-beam computed tomography (CBCT) images were used to analyse skeletal, alveolar, and dental changes. RESULTS: Both MSE and custom MARPE groups achieved significant skeletal and dentoalveolar expansion. However, the custom MARPE group exhibited notably greater expansion in several metrics; in the axial plane, the average expansion was 4.68±1.35mm and 3.37±1.53mm at the anterolateral maxillary walls and 3.99±1.35mm and 3.28±1.19mm at the greater palatine foramen region for custom MARPE and MSE groups, respectively (P<0.01). In coronal plane, the custom MARPE showed significantly greater transverse expansion at the mid-nasal, basal, alveolar, and dental levels. CONCLUSION: Both MARPE systems are effective for maxillary expansion. However, the custom-fabricated MARPE may offer more favourable results, with broader and more uniform skeletal expansion. This can be especially beneficial for patients with specific anatomical requirements.

Comparative biomechanical analysis of four different tooth- and bone-borne frog appliances for molar distalization : A three-dimensional finite element study.

PURPOSE: The purpose of this study was to analyze the biomechanical effects of four different designs of frog appliances for molar distalization using finite element analysis. METHODS: A three-dimensional finite element model including complete dentition, periodontal ligament, palatine, and alveolar bone was established. Four types of frog appliances were designed to simulate maxillary molar distalization: tooth-button-borne (Type A), bone-borne (Type B), bone-button-borne (Type C), and tooth-bone-borne (Type D) frog appliances. A force of 10 N was applied simulating a screw in the anteroposterior direction. To assess the von Mises stress distribution and the resultant displacements in the teeth and periodontal tissues, geometric nonlinear theory was utilized. RESULTS: Compared to the conventional tooth-borne frog appliance (Type A), the bone-borne frog appliances showed increased first molar distalization with enhanced mesiolingual rotation and distal tipping, but the labial inclination and intrusion of the incisors were insignificant. When replacing the palatal acrylic button with miniscrews (Types B and D), more anchorage forces were transmitted from the first premolar to palatine bone, which was further dispersed by the assistance of a palatal acrylic button (Type C). CONCLUSIONS: Compared to tooth-borne frog appliances, the bone-borne variants demonstrated a clear advantage for en masse molar distalization. The combined anchorage system utilizing palatal acrylic buttons and miniscrews (Type C) offers the most efficient stress distribution, minimizing force concentration on the palatine bone.

A comparison of maxillofacial growth in Chinese children with isolated cleft palate treated with two different palatoplasty techniques without relaxing incisions: a preliminary study.

OBJECTIVE: To assess the maxillofacial growth of patients with isolated cleft palate following the Sommerlad-Furlow modified technique and compare it with the effect of the Sommerlad technique. STUDY DESIGN: A Retrospective Cohort Study. METHODS: A total of 90 participants, 60 patients with non-syndromic isolated soft and hard cleft palate (ISHCP) underwent primary palatoplasty without relaxing incision (30 patients received the Sommerlad-Furlow modified (S-F) technique and 30 received Sommerlad (S) technique). While the other 30 were healthy noncleft participants with skeletal class I pattern (C group). All participants had lateral cephalometric radiographs at least 5 years old age. All the study variables were measured by using stable landmarks, including 11 linear and 9 angular variants. RESULTS: The means age at collection of cephalograms were 6.03 ± 0.80 (5-7 yrs) in the S group, 5.96 ± 0.76 (5-7 yrs) in the S-F group, and 5.91 ± 0.87 (5-7 yrs) in the C group. Regarding cranial base, the results showed that there were no statistically significant differences between the three groups in S-N and S-N-Ba. The S group had a significantly shortest S-Ba than the S-F & C groups (P = 0.01), but there was no statistically significant difference between S-F and C groups (P = 0.80). Regarding skeletal maxillary growth, the S group had significantly shorter Co-A, S- PM and significantly less SNA angle than the C group (P = < 0.01). While there was no significant difference between S-F & C groups (P = 0.42). The S group had significantly more MP-SN inclination than the C group (P = < 0.01). Regarding skeletal mandibular growth, there were no statistically significant differences in all linear and angular mandibular measurements between the three groups, except Co-Gn of the S group had a significantly shorter length than the C group (P = 0.05). Regarding intermaxillary relation, the S-F group had no significant differences in Co-Gn-Co-A and ANB as compared with the C group. The S group had significantly less ANB angle than S-F & C groups (P = 0.01 & P = < 0.01). In addition, there were no significant differences in all angular occlusal measurements between the three groups. CONCLUSION: As a preliminary report, Sommerlad-Furlow modified technique showed that maxillary positioning in the face tended to be better, and the intermaxillary relationship was more satisfactory than that in Sommerlad technique when compared them in healthy noncleft participants.

Impact of relaxing incisions on maxillofacial growth following Sommerlad-Furlow modified technique in patients with isolated cleft palate: a preliminary comparative study.

OBJECTIVE: To estimate the impact of relaxing incisions on maxillofacial growth following Sommerlad-Furlow modified technique in patients with isolated cleft palate. STUDY DESIGN: A Retrospective Cohort Study. METHODS: A total of 90 participants, 60 patients with non-syndromic isolated soft and hard cleft palate underwent primary palatoplasty (30 patients received the Sommerlad-Furlow modified technique without relaxing incision (S.F-RI group), and 30 received Sommerlad-Furlow modified technique with relaxing (S.F+RI group) with no significant difference found between them regarding the cleft type, cleft width, and age at repair. While the other 30 were healthy noncleft participants with skeletal class I pattern as a Control group. The control group (C group) was matched with the patient groups in number, age, and sex. All participants had lateral cephalometric radiographs at least 5 years old age. The lateral cephalometric radiographs were taken with the same equipment by the same experienced radiologist while the participants were in centric occlusion and a standardized upright position, with the transporionic axis and Frankfort horizontal plane parallel to the surface of the floor. A well-trained assessor (S. Elayah) used DOLPHIN Imaging Software to trace twice to eliminate measurement errors. All the study variables were measured using stable landmarks, including 12 linear and 10 angular variants. RESULTS: The mean age at collection of cephalograms was 6.03 ± 0.80 in the S.F+RI group, 5.96 ± 0.76 in the S.F-RI group, and 5.91 ± 0.87 in the C group. Regarding cranial base, the results showed no statistically significant differences between the three groups in S-N and S-N-Ba. While the S.F+R.I group had a significantly shortest S-Ba than the S.F-R.I & C groups (P = 0.01 & P < 0.01), but there was no statistically significant difference between S.F-R.I & C groups (P = 0.71). Regarding the skeletal maxilla, there was no significant difference between the S.F+R.I and S.F-R.I groups in all linear measurements (N-ANS and S-PM) except Co-A, the S.F+R.I group had significantly shorter Co-A than the S.F-R.I & C groups (P = < 0.01). While the angular measurement, S.F+R.I group had significantly less SNA angle than the S.F-R.I & C groups (P = < 0.01). Regarding mandibular bone, there were no statistically significant differences in all linear and angular mandibular measurements between the S.F+R.I and S.F-R.I.groups. Regarding intermaxillary relation, the S.F+R.I group had significant differences in Co-Gn-Co-A and ANB compared to the S.F-R.I & C groups (P = < 0.01). While there was no statistically significant difference in PP-MP between the three groups. CONCLUSION: As a preliminary report, the Sommerlad-Furlow modified technique without relaxing incisions was found to have a good maxillary positioning in the face and a satisfactory intermaxillary relationship compared to the Sommerlad-Furlow modified technique with relaxing incisions.

Three-dimensional assessment of the favorability of maxillary posterior teeth intrusion in different skeletal classes limited by the vertical relationship with the maxillary sinus floor.

BACKGROUND: Understanding the anatomical relationship between the maxillary sinus floor (MSF) and the posterior maxillary teeth (PMT) is important when planning the orthodontic intrusion of the posterior teeth. This study aimed to determine the vertical relationship between posterior maxillary teeth and maxillary sinus floor in different skeletal classes in the Chinese adult population. METHODS: This is a retrospective cross-sectional study involved cone beam computed tomography images of 298 adult patients (145 males and 153 females) between 20 and 45 years old. The sample was categorized according to A point, Nasion, B point (ANB) angle into 102 Class I, 102 Class II, and 94 Class III malocclusion. Non-parametric Wilcoxon Mann-Whitney U and Kruskal-Wallis tests were used to compare the studied groups. The Intra-class Correlation Coefficient (ICC) was used to assess the intra- and inter-observer reliability analysis. RESULTS: Overall, there was a statistically significant difference in the mean distance between both genders (P < 0.001). The measured distance increased with age in all posterior tooth roots (P < 0.001). The root apex in the sagittal view appeared to be closer to the maxillary sinus than in the coronal view; 2.2 ± 4.3 and 3.1 ± 5.5 mm, respectively. The most frequent root scores were Type 1 and Type 2P. In both sagittal and coronal views, Class I demonstrated a higher Type 2P prevalence, whereas Class III showed a lower prevalence. The second molars' mesiobuccal root had the largest number of penetration in the three examined skeletal classes. CONCLUSIONS: Maxillary molars of Class I malocclusion with the majority of Type 2P root-sinus relationship have the highest possible risk of root resorption during molar intrusion due to cortical bone encroachment, while Class III malocclusion showed the least possible risk.

Comprehensive three-dimensional positional and morphological assessment of the temporomandibular joint in skeletal Class II patients with mandibular retrognathism in different vertical skeletal patterns.

BACKGROUND: Only a few studies have used 3D cone-beam computed tomography (CBCT) analysis to evaluate the positional and morphological characteristics of the temporomandibular joint (TMJ) in adults with skeletal Class II. No studies have focused on the case of skeletal Class II with mandibular retrognathism in different vertical skeletal patterns. As a result, this study aimed to evaluate and compare the position and morphology of TMJ in adults with skeletal Class II with mandibular retrognathism in different vertical skeletal patterns to the position and morphology of TMJ in the normal Chinese adult population in three dimensions. METHODS: This retrospective study analyzed CBCT images of 80 adult patients. Subjects with skeletal Class II with a normal sagittal position of the maxilla and mandibular retrognathism were classified according to the mandibular angle and facial height ratio into three groups of 20 subjects each: hypodivergent, normodivergent, and hyperdivergent groups, as well as a control group of 20 subjects. The following 3D measurements of TMJ were evaluated: (1) position, parameters, and inclination of the mandibular fossa; (2) position, parameters, and inclination of the mandibular condyle; (3) condyle centralization in their respective mandibular fossae; (4) anterior, posterior, superior, and medial joint spaces; and (5) 3D volumetric measurements of the TMJ spaces. Measurements were statistically analyzed by one-way ANOVA test, followed by Tukey's post hoc test. RESULTS: Significant differences were found in the hyperdivergent and hypodivergent groups compared with the normal group in the vertical and anteroposterior mandibular fossa position, vertical condylar inclination, and condylar width and length. The hyperdivergent group showed the significantly highest condylar inclination with the midsagittal plane; anterior and superior positioning of the condyle; smallest anterior, superior, and medial joint spaces; and largest volumetric total joint space relative to the two other groups. CONCLUSIONS: The condyle-fossa position and morphology differ with various vertical facial patterns in individuals with skeletal Class II mandibular retrognathism. These differences could be considered during TMD diagnosis and orthodontic treatment.