Marziyeh Shafizadeh; Azita Tehranchi; Saeed Reza Motamedian
Abstract
Context: The labial cortical bone may influence the outcomes of several treatments including fresh socket implant placement and orthodontic treatments. A thin labial plate may contribute to increased risks of periodontal consequences during dental procedures. Acknowledgment of the average values may ...
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Context: The labial cortical bone may influence the outcomes of several treatments including fresh socket implant placement and orthodontic treatments. A thin labial plate may contribute to increased risks of periodontal consequences during dental procedures. Acknowledgment of the average values may guide clinicians to take particular considerations in making treatment decisions. Therefore, this study aimed to systematically review the labial cortical bone thickness (LBT) in the anterior maxillary teeth.
Objective: The primary purpose of this study was to review the LBT in the anterior maxillary teeth to present the range of average LBT in the global population.
Evidence Acquisition: An electronic search was conducted in PubMed, Embase, ProQuest, Web of Science, and Scopus databases. English studies that measured the LBT in the maxillary anterior teeth using CT or CBCT scans were deemed relevant. Only studies performed on adult patients with a lack of periodontal disease were included.
Results: A total of 49 studies were included. Mean LBT ranged 0.13 - 3.08, 0.29 - 4.2, and 0.36 - 4.5 mm in maxillary central incisor, lateral incisor, and canine, respectively. Expectedly, LBT was affected by the vertical level of the measurement point and increased toward the apex. In total, the LBT in the anterior maxilla ranged from 0.13 to 4.5 mm. In comparison with other populations, a relatively thin labial plate was evidenced in the Iranian populations.
Conclusions: This study showed a wide range of LBT in the esthetic zone. A thin plate in the esthetic area necessitates caution in orthodontic treatments, particularly when tooth expansion or proclination is required. Additionally, wide ranges of reported values which are mostly under 2 mm, highlight the importance of CBCT acquisition before any fresh socket implant placement.
Azita Tehranchi; Nazila Ameli; E. Hasanrezaee
Abstract
Background and aim: The objective of this study was to investigate the relationship between the gonial angle changes and occlusal plan steepness in patients underwent Bilateral Sagittal Split Osteotomy (BSSO) surgery.Materials and method: In this analytical retrospective clinical trial, 18 males and ...
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Background and aim: The objective of this study was to investigate the relationship between the gonial angle changes and occlusal plan steepness in patients underwent Bilateral Sagittal Split Osteotomy (BSSO) surgery.Materials and method: In this analytical retrospective clinical trial, 18 males and 12 females were studied who had been underwent BSSO surgery for mandibular advancement in. Cephalometric landmarks were calculated on the patients' lateral radiographs taken before and 1-6 months postsurgery using Dolphin software. The patients assigned into 3 groups according to different occlusal plan steepness. Landmarks' changes before and after surgery were analyzed by Paired t-test. The changes occurred regarding the normal and flat facial types assessed by Student t-test while the relationship between the presurgical occlusal plan and the landmark changes was evaluated using the Pearson Coefficient.Results: After BSSO, the gonial angle had increased in all patients with the mean value of 6.83ᴼ (P˂0.0001) but occlusal plan steepness increased to an insignificant value (mean 2.82ᴼ). Increased values of the gonial angle were similarly reported in the patients with normal occlusal plan steepness and flat occlusal plan while no significant relationship was found between occlusal plan steepness before the surgery and the gonial angle changes after surgery. However, fair more increase occurred in patients with normal steepness than lower ones. Conclusions: The results showed that there is no significant relationship between the gonial angle changes after surgery and the occlusal plan steepness prior the surgery of BSSO for mandibular advancement.
Azita Tehranchi; Hossein Behnia; Sepideh Soheilifar
Abstract
Background and aim: Bilateral mandibular distraction osteogenesis (BMDO) has been suggested as a suitable method for correcting severe mandibular deficiencies. The purpose of this study was to evaluate the cephalometric changes of patients undergoing BMDO.Materials and methods: Seven patients were selected ...
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Background and aim: Bilateral mandibular distraction osteogenesis (BMDO) has been suggested as a suitable method for correcting severe mandibular deficiencies. The purpose of this study was to evaluate the cephalometric changes of patients undergoing BMDO.Materials and methods: Seven patients were selected for BMDO, all suffering from severe mandibular retrognathia as a result of previous trauma. Pre-treatment (T1), post-treatment (T2) and follow up (T3) cephalograms were obtained. The changes in skeletal and soft tissue parameters were assessed by paired t-test within two time intervals (T1-T2 and T2-T3). Results with a P value <0.05 were considered statistically significant. Results: In patients treated by extra-oral distractor, BMDO improved jaw relationships by increasing SNB (12.1˚) and mandibular length (22.5mm) and decreasing ANB (10.3˚) and Wits (17.2mm). Lower facial height increased significantly (4.5mm). Dental relationships were changed by increasing interincisal angle (24.8˚) and decreasing IMPA (23.2˚) and overjet (8.8mm). Reduction in the distance between upper and lower lip to E-line led to changes in the soft tissue profile. Airway space analysis revealed an increase in the nasopharyngeal space (Nph2) (4.7 mm), the oropharyngeal space (Oph2) (5.4mm) and the posterior airway space (PAS) (9mm). The available cases remained stable during the follow up period.
Conclusion: BMDO improved maxillomandibular discrepancy by lengthening mandibular body. Lower anterior facial height was increased significantly. Lip prominency relative to the nose and the chin was decreased and dental relationships were corrected by the treatment. DO procedure significantly improves the pharyngeal spaces.
Azita Tehranchi; Hossein Behnia; Majid Heidarpour; Bahman Toutiaee; Mohammad Javad Khosropour
Abstract
Aim: Analyzing the changes made during distraction osteogenesis (DO) in asymmetric mandibles.Materials and methods: This study was performed on a three dimensional model of a desiccated mandible, based on a finite element method. The distraction devices were placed with an angle of 90, 60 or 30 degrees ...
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Aim: Analyzing the changes made during distraction osteogenesis (DO) in asymmetric mandibles.Materials and methods: This study was performed on a three dimensional model of a desiccated mandible, based on a finite element method. The distraction devices were placed with an angle of 90, 60 or 30 degrees to the oblique surgical cut. The directions of the pins were such that the 30 and 60 degree pins were placed in a counterclockwise direction relative to the perpendicular pin. The distractors were opened for 15 and 30 mm. The amount and direction of movement of proximal and distal segments and the displacement of pogonion were evaluated in all three planes of space.
Results: In the distal segment, the maximum change in pogonion was seen in 30 degree angle. In the proximal segment, if the distraction device was used with 90 degree angle, the condylar process rotated in the clockwise rotation. In 30 degree angle, this process rotated in a counterclockwise direction and the minimum rotation was seen in 60 degree angle.Conclusion: If gonial angle is to be augmented in a downward direction maximally, the angle of distraction device to the surgical cut is critically important (that is, it should be perpendicular to surgical cut). By use of perpendicular mode, ramus slops more posteriorly. It is better to use the distraction pin with a thirty degree angle if the ramus needs to be uprighted. The oblique surgical cut, irrespective of the distraction pin angle, increases the anterior facial height.
