Lower incisor position vs. symphyseal morphology
Manea I, Abascal-Pineda I, Solano-Mendoza B, Solano-Reina A, Solano-Reina JE. Facial growth pattern: Association between lower incisor position and symphyseal morphology. J World Fed Orthod 2017; 6:147-151
The position of the lower incisors to the underlying mandibular symphysis should be maintained in a healthy relationship throughout orthodontic treatment. The aim of the current study was to analyze and determine if there is a statistically significant correlation between facial growth pattern, Holdaway ratio, symphyseal morphology, and lower incisor position, as well as validate a previous analysis performed by Aki et al. A sample of 100 white adult patients was randomly selected from the University of Seville in Spain. Manual measurements were made from the pre-treatment cephalograms at four different time points by two separate operators. The operators assessed symphyseal height/width (H/A) ratio using the Aki analysis, symphyseal morphology (constructed by point B–menton line and the mandibular plane), and facial growth pattern (determined using the Jarabak-MSE analysis retro-occlusion variable). Facial growth pattern, the Holdaway ratio, and H/A were found to be statistically significant ( P < 0.05). The study concluded that anterior mandibular bone support and lower incisor position differs among patients, and that symphyseal morphology is related to both facial growth pattern and lower incisor inclination. Dolichofacial patterns trend towards a narrower symphysis, while broader symphyses are indicative of brachyfacial patterns. These facial patterns can then be further related to lower incisor position using the Holdaway ratio and symphyseal H/A ratio, which showed that larger degrees of lower incisor proclination are associated with dolichofacial patterns and a narrow symphysis, and more upright lower incisors are associated with brachyfacial patterns and a wider symphysis. Therefore, orthodontists must understand the limitations on lower incisor movements depending on each patient’s symphyseal morphology and facial growth pattern.
Reviewed by Evan Perkins and Spencer White
Panoramic evaluation of microimplant success rate
Park JH, Chae JM, Bay RC, Kim MJ, Lee KY, Chang NY. Evaluation of factors influencing the success rate of orthodontic microimplants using panoramic radiographs. Korean J Orthod 2018; 48(1):30-38
In orthodontics, maintaining adequate anchorage is a common challenge for clinicians. Orthodontic microimplants (OMIs) have allowed orthodontists to achieve maximum anchorage in situations where conventional biomechanics failed to accomplish the desired results, but their failure rates can be problematic. The purpose of this prospective study was to utilize panoramic radiographs to evaluate factors that may influence the success rate of OMIs. The study included 80 participants who received bilateral maxillary buccal OMIs placed between the second premolar and first molar. The OMIs placed were 1.20-1.30 mm in diameter and were placed using a self-drilling hand driver in the attached gingiva adjacent to the mucogingival junction between the roots of the adjacent teeth. The implants were immediately loaded with 50-200 g of force and a panoramic radiograph was captured to evaluate OMI positioning. In this study, treatment success was defined as the OMIs being adequate anchors in the alveolar bone for a minimum of 1 year during the orthodontic treatment. The overall success rate of the OMIs of this study was 85%. OMIs were determined to be more successful in adults than in teens. In addition, placing the OMI more apically and increasing its length increased success by 1.53% and 1.81%, respectively. Finally, this study concluded that placing the OMI on the interradicular midline rather than placing it mesial or distal proved to have a success rate of 92.9% compared to 87.0% and 81.8%, respectively. Although this study is limited by the fact that the OMI position was determined based on panoramic radiographs, the results still provide important clinical insight for improving OMI success rates.
Reviewed by Courtney Burns and Laurel Cook
Panoramic evaluation of microimplant success rate
Park JH, Chae JM, Bay RC, Kim MJ, Lee KY, Chang NY. Evaluation of factors influencing the success rate of orthodontic microimplants using panoramic radiographs. Korean J Orthod 2018; 48(1):30-38
In orthodontics, maintaining adequate anchorage is a common challenge for clinicians. Orthodontic microimplants (OMIs) have allowed orthodontists to achieve maximum anchorage in situations where conventional biomechanics failed to accomplish the desired results, but their failure rates can be problematic. The purpose of this prospective study was to utilize panoramic radiographs to evaluate factors that may influence the success rate of OMIs. The study included 80 participants who received bilateral maxillary buccal OMIs placed between the second premolar and first molar. The OMIs placed were 1.20-1.30 mm in diameter and were placed using a self-drilling hand driver in the attached gingiva adjacent to the mucogingival junction between the roots of the adjacent teeth. The implants were immediately loaded with 50-200 g of force and a panoramic radiograph was captured to evaluate OMI positioning. In this study, treatment success was defined as the OMIs being adequate anchors in the alveolar bone for a minimum of 1 year during the orthodontic treatment. The overall success rate of the OMIs of this study was 85%. OMIs were determined to be more successful in adults than in teens. In addition, placing the OMI more apically and increasing its length increased success by 1.53% and 1.81%, respectively. Finally, this study concluded that placing the OMI on the interradicular midline rather than placing it mesial or distal proved to have a success rate of 92.9% compared to 87.0% and 81.8%, respectively. Although this study is limited by the fact that the OMI position was determined based on panoramic radiographs, the results still provide important clinical insight for improving OMI success rates.
Reviewed by Courtney Burns and Laurel Cook
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