The Maxilla-Mandibular Discrepancies through Soft-Tissue References: Reliability and Validation of the Anteroposterior Measurement.

This research aimed to identify a new measurement to diagnose the sagittal maxillary and mandibular difference that considers the patient's profile (soft tissue Wits appraisal: obtained by projecting points A and B on the occlusal plane and subsequently measuring the linear distance between the two points). This new measurement was compared to the conventional Wits appraisal obtained to diagnose sagittal jaw discrepancy. In total, 300 subjects (162 males, 138 females) aged between 6 and 50 years requiring orthodontic treatment were analyzed. The cephalometric tracings on the pre-treatment lateral cephalometric radiographs were obtained and the two measurements taken were the Wits appraisal and a new measurement which were both calculated and compared. The analysis of the linear correlations between the conventional Wits value and the measurement obtained on the soft-tissue were undertaken. The relevance was established at 5% (p < 0.05). The mean values were also calculated within sex and age classes, and comparisons between sexes were obtained employing the t test Student's for independent samples. Subsequently, chi-square analysis was also utilized to verify the sex distributions in the age groups considered. The results obtained suggested that these two measurements were significantly correlated with each other, with no characteristic patterns of sex or age. These data allowed an estimation of the reference values of the new measurement (-1.9 mm and 5.4 mm for patients with Class I molar relationship) showing that the former was more variable than the latter. The new measurement could allow for an accurate evaluation of the jaws sagittal discrepancy from soft tissue analysis.

Tratamiento de la clase III esquelética máxilo-mandibular con twin block / Treatment of skeletal Class III maxillo-mandibular relationship with the twin block appliance

RESUMEN Introducción: la clase III esquelética máxilo-mandibular se caracteriza por la relación no fisiológica de los arcos dentarios, perfil cóncavo, discrepancia sagital máxilo-mandibular y alteraciones funcionales que perturban el funcionamiento del sistema estomatognático. En la literatura nacional e internacional no existe evidencia de la eficacia del tratamiento con twin block de la clase III esquelética máxilo-mandibular. Objetivo: evaluar el tratamiento de la clase III esquelética máxilo-mandibular con el uso de twin block. Material y Métodos: se realizó un estudio de intervención de tipo cuasi-experimental, en 43 pacientes con clase III esquelética máxilo-mandibular, en la Clínica Universitaria de Especialidades Estomatológicas "Manuel Cedeño", en el período de enero de 2018 a junio de 2019. Se estudiaron las variables: relación de oclusión, clasificación esquelética máxilo-mandibular, disfunción de la articulación temporomandibular y estética facial. A todos los pacientes se les aplicó el twin block como parte del tratamiento ortopédico-funcional. Resultados: inicialmente el 86,04% de los pacientes tenían una mesioclusión, la que se modificó a neutroclusión en el 81,39%. La clasificación esquelética se corrigió en el 88,37% de los casos. La disfunción de la articulación temporomandibular mejoró, a leve, en el 51,16% de los pacientes. La estética facial resultó no afectada en el 83,72%. Conclusiones: Con el uso de twin block se corrige la relación de oclusión dentaria y la clase III esquelética máxilo-mandibular, además de ser una opción terapéutica que mejora la disfunción de la articulación temporomandibular y la estética facial en pacientes con esta anomalía dentomaxilofacial.

ABSTRACT Introduction: Skeletal Class III maxillo-mandibular relationship is characterized by the non-physiological relationship between the dental arches, concave profile, maxillo-mandibular sagittal discrepancy and functional alterations that disturb the functioning of the stomatognathic system. In the national and international literature, there is no evidence of the effectiveness of treatment of Skeletal Class III maxillo-mandibular relationship with the use of twin block appliance. Objective: To evaluate the treatment of skeletal Class III maxillo-mandibular relationship with the use of twin block appliance. Material and Methods: A quasi-experimental intervention study was conducted in 43 patients with skeletal Class III maxillo-mandibular relationship at Manuel Cedeño Dental Specialties University Clinic during the period between January 2018 and June 2019. The study variables were: occlusion ratio, maxillo-mandibular skeletal classification, temporomandibular joint dysfunction and facial esthetics. The twin block appliance was applied to all patients as part of the orthopedic functional treatment. Results: Initially, 86,04 % of the patients had a mesioclusion, which was modified to neutroclusion in 81,39 %. Skeletal classification was corrected in 88,37 % of cases. Temporomandibular joint dysfunction improved to mild in 51,16 % of patients. Facial esthetics was not affected in 83,72 %. Conclusions: The ratio of dental occlusion and class III maxillo-mandibular skeletal relationship are corrected with the use of a twin block appliance, besides being a therapeutic choice that improves dysfunction of the temporomandibular joint and facial esthetics in patients with this dentomaxillofacial anomaly.