Cambios en incisivos y su relación con el punto A y el ángulo nasolabial en pacientes Clase II división 2 tratados con y sin extracciones en el Centro Dental Docente UPCH / Changes in incisors and their relationship with point A and nasolabial angle in Class II division 2 patients treated with and without extractions at the UPCH Teaching Dental Center

RESUMEN Antecedentes : Diversos estudios describen las características de la maloclusión clase II-2, sin embargo, son escasos los estudios que evalúan las repercusiones del tratamiento sobre tejidos blandos y esqueléticos. Objetivo : Evaluar los cambios post tratamiento en inclinación y posición incisiva y su relación con el ángulo nasolabial (ANL) y el punto A (PA) en pacientes Clase II división 2, con y sin extracciones en casos de la especialidad de Ortodoncia de la Universidad Peruana Cayetano Heredia. Material y métodos: se realizaron trazados manuales y mediciones de 62 radiografías cefalométricas laterales (31 pre y 31 post-tratamiento), de pacientes con maloclusión de Clase II división 2. El análisis estadístico se realizó con SPSS 21.0 para Windows. Resultados : Se observan proinclinación y protrusión incisiva en todos los pacientes. En pacientes con exodoncias el ANL presentó cambios no significativos, pero correlaciones significativas: cuando aumentó la inclinación incisiva inferior disminuyó el ANL; cuando aumentó el ANL, aumentó el ángulo interincisal (AII). El punto A (PA) experimentó cambios y correlaciones, pero no significativas. En pacientes sin exodoncias no se encontraron correlaciones ni cambios significativos en PA ni en ANL. Las mujeres tratadas sin exodoncia no presentaron cambios significativos, en los hombres los cambios más significativos fueron la inclinación y protrusión incisiva inferior. En los casos con exodoncias en hombres fue el AII; y en las mujeres el AII y el ángulo incisivo superior/ plano palatino. Conclusiones: Existe una relación entre los cambios que se producen en los incisivos y el ANL y PA, aunque la mayoría no son estadísticamente significativos.

ABSTRACT Background : There are studies evaluating cephalometric parameters in Class II division 2 patients. There are no similar investigations in Peru. Objective : To evaluate post-treatment changes in incisor inclination and position and their relationship with the nasolabial angle (ANL) and point A (PA) in Class II division 2 patients, with and without extractions in cases of the Orthodontic specialty program of the Universidad Peruana Cayetano Heredia. Material and methods : manual tracing and measurements of 62 lateral cephalometric radiographs (31 pre and 31 post-treatment) were performed, of patients with Malocclusion Class II division 2. Statistical analysis was performed with SPSS 21.0 for Windows. Results : There was proinclination and incisive protrusion in all patients. In patients with extractions, the ANL presented non-significant changes, but significant correlations: when the lower incisor inclination increased, the ANL decreased; when ANL increased, the interincisal angle (AII) increased. Point A (PA) experienced changes and correlations, but not significant. In patients without extractions, no correlations or significant changes were found in BP or ANL. Women treated without extraction did not show significant changes, in men the most significant changes were lower incisor inclination and protrusion. In the cases with extractions in men it was AII; and in women the AII and the upper incisor angle / palatal plane. Conclusions: There is a relationship between the changes that occur in the incisors and the ANL and PA, although most are not statistically significant.

Midpalatal suture density ratio after rapid maxillary expansion evaluated by cone-beam computed tomography.

INTRODUCTION: Identifying the stage of midpalatal suture (MPS) fusion is essential for rapid maxillary expansion (RME). The objective of this study was to evaluate the relationship between MPS density ratio and the skeletal response after RME using cone-beam computed tomography (CBCT). METHODS: CBCT scans of 64 patients (age, 13.81 ± 1.68 years; 42 females and 22 males) who underwent RME as part of comprehensive orthodontic treatment were used for this study. Two CBCT records were made at T1 (pre-RME) and T2 (post-RME). MPS density was assessed by gray scale and the skeletal effects through linear measurements: greater palatine foramina, the width of the nasal cavity (NW), infraorbital foramina. The data were collected at 4 different times: baseline, 24 hours, 48 hours, and 4 weeks. RESULTS: There was no statistically significant correlation between MPS density ratio and greater palatine foramina or infraorbital foramina. Negative correlations with MPS density ratio are presented with the difference of age post-RME and pre-RME (r = -0.46, P = 0.033) in males, and NW (r = -0.41, P = 0.007) in females. A significant association between gender and the MPS density ratio was found (P = 0.015) in females. CONCLUSIONS: There is a weak negative correlation between the MPS density ratio and the difference of age post-RME and pre-RME in males and the NW in females. Females presented greater density ratios than males. MPS density ratio through CBCT does not appear to be an adequate parameter to predict the skeletal effect in adolescent patients and young adults.

Evaluation of the nasal septum and depth of palatal arch in different facial vertical patterns: A Cone-Beam Computed Tomography Study.

OBJECTIVE: The purpose of this study was to evaluate the nasal septum and the depth of posterior palatal arch in the different facial vertical patterns using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: A total of 143 CBCTs were analysed (53 normodivergents, 26 hypodivergents, and 64 hyperdivergents) using the software Real Scan 2.2. On the coronal view, the following measurements were taken, palatal interalveolar length (PIL), palatal arch depth (PAD), maxillopalatal arch angle (MPAA), septal vertical length (SVL), deviated septal length (DSL), and deviated septal curve angle (DSCA). Using the program Stata v16.0, we obtained the mean, standard deviation and median values. The identification of significant differences between facial biotypes was performed using the one-way ANOVA test and H of Kruskal-Wallis test, considering a significance level of 0.05. RESULTS: The hypodivergent group got the highest PIL and MPAA (49.6mm and 118.1° respectively), with statistically significant differences (P<0.05) between this group and the hyperdivergent group. Statistically significant differences were found by gender for the SNMeGo, PFH, AFH, and the relationship between the facial heights, where the males had the highest values. Additionally, PIL and SVL also had the highest values for males (48.8mm and 63.6mm respectively). CONCLUSIONS: Patients presenting with greater hyperdivergence have shorter interalveolar distances and smaller maxillopalatal arch angles.

Evaluation of the palatal bone in different facial patterns for orthodontic mini-implants insertion: A cone-beam computed tomography study.

OBJECTIVE: Evaluate the height, thickness and cortical density of the palatal bone of adults with different vertical facial patterns using Cone-Beam Computed Tomography (CBCT). METHODS: This study analyzed 75 CBCTs of patients between 18 and 35 years old (45 men and 30 women). The CBCTs were classified into three groups based on their facial pattern: normodivergent, hypodivergent and hyperdivergent as determined from lateral cephalograms synthesized from the CBCTs. The height, cortical thickness and cortical density of the palatal bone were measured at 4, 8, 12, 16 and 20mm posterior to the incisive foramen, and at 3, 6 and 9mm lateral to the midpalatal suture. ANOVA with Tukey post-hoc tests were used for analysis of the data, at significance level of p< 0.05. RESULTS: The hypodivergent pattern had a significant difference and the greatest height and cortical thickness of the palatal bone, followed by the hyperdivergent and the normodivergent patterns. No significant differences were found in minimum and maximum values of cortical density. CONCLUSION: The palatal bone is a favorable anatomical area to install different orthodontic temporary anchorage devices (TADs), where individuals with the hypodivergent vertical facial pattern have a higher height and cortical thickness of the palatal bone, followed by the hyperdivergent pattern and finally the normodivergent pattern. No significant differences in the cortical density of the palatal bone in the three facial patterns were found.

Mesiodistal sizes and intermaxillary tooth-size ratios of two populations; Spanish and Peruvian. A comparative study.

INTRODUCTION: Adequate tooth-size ratios are required to ensure the satisfactory outcome of orthodontic treatment. Consequently, various methods of measuring tooth-size ratios have been developed being the Bolton ratio the most commonly accepted, known and used one. This ratio depending directly on mesiodistal tooth size has been associated with different ethnic backgrounds. Some authors suggest the need for specific standards for every population. OBJECTIVES: The objectives of our study were; to measure and to compare mesiodistal tooth sizes and the Anterior and Overall Bolton ratios in two different populations, one Peruvian and the other Spanish with the same digital method. MATERIAL AND METHODS: The sample included 149 individuals composed of two groups; 99 Spanish (mean age 14.19), 65 being females and 34 males and 50 Peruvian (mean age 14.46), 18 being males and 32 females. The mesiodistal sizes of each of the patients were measured using a digital method and the Anterior and Overall Bolton ratios were calculated. RESULTS: Tooth size does indeed involve a strong ethnic component, and the Anterior Bolton ratio is specific for each ethnic group. CONCLUSIONS: The conclusions are; tooth sizes of the Peruvian population were greater than those of the Spanish population. The Anterior Bolton ratio of Peruvian individuals was greater than that of the Spanish, whereas no differences were found for Overall Bolton ratio. These differences suggest the need for specific standards for the Spanish and Peruvian population.