Influence of Class II Elastics on Centric Relation and Centric Occlusion Discrepancy after Orthodontic Treatment / Influencia de los Elásticos de Clase II sobre la Discrepancia de Relación Céntrica para la Oclusión Céntrica Después del Tratamiento Ortodóncico

ABSTRACT: The objective of this study was to verify the influence of the use of Class II intermaxillary elastics on centric relation (CR) to centric occlusion (CO) occlusal discrepancy. A total of 30 patients had been at the contention stage for at least three months were divided in two groups: G1 - 15 had been submitted to intramaxillary orthodontic mechanics only, and G2 - 15 had used Class II intermaxillary elastics. Distances of horizontal and vertical overlap and the distance or coincidence of the mandibular dental midline in relation to the maxillary midline were measured in CR and CO positions. Intergroup comparisons were performed using the Mann-Whitney test. No statistically significant differences (P>0.05) were found between G1 and G2. Both in the horizontal and vertical directions, these discrepancies were smaller than or equal to 1mm in 96.66 % of the patients. In the transverse plane, there was no discrepancy in 63.33 % of the patients, and in 33.33 % these discrepancies were equal to 0.5 mm. The use of Class II elastic didn't be capable of increasing the occlusal discrepancies between CR and CO.

RESUMEN: El objetivo de este estudio fue verificar la influencia del uso de los elásticos intermaxilares Clase II en la discrepancia oclusal entre la relación céntrica (RC) y la oclusión céntrica (OC). Un total de 30 pacientes que permanecieron en la fase de contención durante al menos tres meses se dividieron en dos grupos: G1 - 15 fueron sometidos solamente a la mecánica ortodóncica intramaxilar, y G2 - 15 habían utilizado elásticos de clase II intermaxilar. Se midieron las distancias de traslapo horizontal y vertical y la distancia o coincidencia de la línea mediana dentaria mandibular con respecto a la línea mediana maxilar en las posiciones RC y OC. Las comparaciones entre grupos se realizaron mediante la prueba de Mann-Whitney. No se encontraron diferencias estadísticamente significativas (P> 0.05) entre G1 y G2. Tanto en las direcciones horizontal como vertical, estas discrepancias fueron menores o iguales a 1 mm en el 96,66 % de los pacientes. En el plano transversal, no hubo discrepancia en el 63,33 % de los pacientes, y en un 33,33 % estas discrepancias fueron iguales a 0,5 mm. El uso de la clase II elástica no logró aumentar las discrepancias entre RC y OC.

Thickness and marking quality of different occlusal contact registration strips

Objectives Evaluate the thickness and the marking quality of different occlusal contact registration strips (OCRS) and a possible correlation between them. Material and Methods The following OCRS were selected: Accufilm II, BK20, BK21, BK22, BK23, BK28, and BK31. The thickness was measured in three points of the OCRS with an electronic measuring device (TESA), and the mean was calculated. To produce the marks on the strips, composite resin specimens were adapted to a universal testing machine (Versat 2000) with 40 kgf load cell at a speed of 1.0 mm/min. The mark images were photographed with a stereoscopic microscope (Stemi SV11) and processed and analyzed by the 550-Leica Qwin® analyzer. Results Values (μm) found in the 1st and 2nd thickness measurements were: Accufilm II - 16.4 and 14.2; BK20 - 10.0 and 8.1; BK21 - 9.5 and 8.0; BK22 - 9.7 and 8.7; BK23 - 9.8 and 7.9; BK28 - 12.8 and 10.0; and BK31 - 8.4 and 8.0, respectively. The mean (mm2) values found in the mark areas were: Accufilm II - 0.078; BK20 - 0.035; BK21 - 0.045; BK22 - 0.012; BK23 - 0.022; BK28 - 0.024; and BK31 - 0.024. The results were submitted to the Kruskal-Wallis (p<0.05) and Pearson’s correlation tests. Conclusions Only in the 2nd measurement, the OCRS thickness observed was similar to the value indicated by the manufacturers; the Accufilm II and the BK28 strips showed the better marks; and no correlation was found between the thickness and the marking area. .

Proporção divina em indivíduos oclusões classes I, II e III esqueléticas em radiografias cefalométricas laterais / Proporción divina en pacientes con oclusión clases I, II y III esqueléticas en radiografías cefalométricas laterales / Divine proportion in patients with skeletal occlusion classes I, II and III on lateral cephalometric radiographs

Introdução: o conceito inicial de beleza remete a um conjunto que engloba harmonia e equilíbrio das proporções faciais estabelecidas pelas estruturas esqueléticas, dentárias e de tecidos moles. Objetivo: o objetivo deste estudo foi analisara proporção divina em radiografias cefalométricas laterais de 93 indivíduos brasileiros adultos, acima de 18 anos, de ambos os gêneros, com classes I, II e III esqueléticas, não submetidos a tratamento ortodôntico, por meio do software de cefalometria Aurea Ceph. Métodos: para análise estatística, foi aplicada a análise de variância ANOVA, teste Tukey e T de Studentem nível de significância de 5 porcento. Resultados: das sete razões estudadas, quando se avaliou as classes, evidenciou-se diferença estatisticamente significante entre a relação (N-Ena/V1S-DM16) nas classes I e III eas relações (A-Pog/V1-C1MS e A-Pog/V1S-MD16) nas classes II e III. Quando se comparou as razões nas diferentes classes em relação ao número áureo (1 618) houve diferença estatisticamente significante na classe I para as razões (N-Ena/V1S-DM16, V1S-C1MS/C1MS-DM16 e Ena-Me/AB); na classe II para as razões (A-Pog/V1-C1MS e A-Pog/V1S-MD16); e na classe III para as razões (N-Ena/V1S-DM16, Ena-Enp/V1S-C1MS, V1S-C1MS/C1MS-DM16 e Ena-Me/AB). Conclusões: de acordo com a metodologia empregada e os resultados obtidos, concluiu-se que das sete razões analisadas, a classe I apresentou três razões divinas, a classe II duas e a classe III quatro. O grupo classe II apresentou razões divinas com componente dentário e medidas verticais, sugerindo que a magnitude do erro sagital é importante no conceito da estética facial(AU)

Introducción: el concepto inicial de la belleza se refiere a un conjunto con la armonía y el equilibrio de las proporciones faciales establecidos por el tejido óseo, dental y suave. Objetivo: el objetivo de este estudio fue analizar la divina proporción en las radiografías cefalométricas de 93 individuos brasileños adultos, de 18 años, de uno y otro géneros, con las clases I, II y III del esqueleto, y no sometidos a un tratamiento de ortodoncia por medio de software de cefalometría Áurea Ceph". Métodos: el análisis estadístico se aplicó al análisis de varianza ANOVA, prueba de Tukey y prueba t de Student. El nivel de significación fue de 5 por ciento. Resultados: de los siete ratios estudiados, hubo una diferencia estadísticamente significativa entre las proporciones al comparar las clases en (N-Ena/V1S-DM16) clases I y III y (A-Pog/V1-C1MS, A-Pog/V1S-MD16) clases II y III. Cuando se comparó con las proporciones en las diferentes clases en relación con el número de oro (1 618), hubo diferencia estadísticamente significativa en la clase I para las (N-Ena/V1S-DM16, razones V1S-C1MS/C1MS-DM16, Ena-Me/AB), y en clase II de (A-Pog/V1-C1MS razones, A-Pog/V1S-MD16) y clase III para los (N-Ena/V1S-DM16 razones, Ena-Enp/V1S-C1MS, V1S-C1MS/C1MS-DM16, Ena-Me/AB). Conclusiones: de acuerdo con la metodología utilizada y los resultados obtenidos, se concluyó que en siete de las razones expuestas, la clase que tenía tres razones áureas se observó en dos y cuatro, clase II a clase III. El grupo de clase II fueron razones áureas con componente dental y horizontal, lo que sugiere que la magnitud del error es importante en el concepto de estética facial sagital. El grupo de clase II fueron razones áureas con componente dental y medidas verticales, y también sugiere que la magnitud del error es importante en el concepto de estética facial sagital(AU)

Introduction: the original concept of beauty refers to a set of harmony and balance features determined by bone, dental and soft tissue. Objective: the purpose of this study was to analyze divine proportion as reflected on cephalometric radiographs of 93 Brazilian subjects of both sexes aged 18 with skeletal classes I, II and III, not undergoing orthodontic treatment. The analysis was based on cephalometric software Aurea Ceph. Methods: statistical analysis was performed with ANOVA, Tukey's test and Student's t test. The significance level was 5 percent. Results: the seven ratios studied showed a statistically significant difference between proportions when comparing (N-Ena/V1S-DM16) classes I and III, and (A-Pog/V1-C1MS, A-Pog/V1S-MD16) classes II and III. When proportions in the different classes were compared with the golden number (1 618), a statistically significant difference was found in class I for (N-Ena/V1S-DM16, V1S-C1MS/C1MS-DM16, Ena-Me/AB), in class II for (A-Pog/V1-C1MS, A-Pog/V1S-MD16) and in class III for (N-Ena/V1S-DM16, Ena-Enp/V1S-C1MS, V1S-C1MS/C1MS-DM16, Ena-Me/AB). Conclusions: based on the methodology used and the results obtained, it was concluded that in seven of the ratios presented, the class with three golden ratios was found in two and four, class II to class III. The class II group were golden ratios with a dental and horizontal component, suggesting that the magnitude of the error is relevant to the concept of sagittal facial aesthetics. The class II group were golden ratios with a dental component and vertical measurements, also suggesting that the magnitude of the error is relevant to the concept of sagittal facial aesthetics(AU)

Influence of high expansion dental stone used as investing medium on the changes in occlusal vertical dimension of complete dentures

Despite advances in materials and techniques, complete dentures made of acrylic resin experience an increase in the occlusal vertical dimension [OVD] during processing. Many factors that affect the OVD of complete dentures are known. However, no study has examined the effect of using high-expansion dental stone [type V] as an investing material on the OVD. This study investigated the effects of using a high-expansion dental stone as an investing material on changes in the OVD of complete dentures. Twenty sets of simulated upper and lower dentures were processed by the compression molding technique. Specimens were equally divided into 2 groups. In the dental stone type III [DST III] group, the lower, middle, and upper parts of a flask were filled with DST III. In the dental stone type V [DST V] group, the procedure was the same as in the DST III group, except that the middle layer was made of high-expansion DST V. Changes in the OVD were measured before and after denture processing. Collected data were analyzed with t-test statistics. Differences were considered statistically significant at the 95% confidence level. Both groups showed a small increase in the OVD as a result of processing, but the OVD increase was significantly less in the DST V group compared to the DST III group. High-expansion DST V can be recommended as an investing material to reduce the increase in the OVD that may occur while processing complete dentures

Moldagem de transferência e registro interoclusal: técnica diferenciada / Transfer molding and interocclusal record: differentiate technique

O sucesso da reabilitação oral depende de precisão tanto na moldagem quanto na montagem no articulador. Quando temos uma prótese em rebordo de extremidade livre, com grandes espaços edêntulos, a intercuspidação torna-se sujeita a erros e um registro estável e preciso da relação interoclusal é necessário. O objetivo desse artigo é apresentar uma técnica de moldagem de transferência que, ao unir os cilindros para a moldagem, já realizamos o registro interoclusal, obtendo o modelo de trabalho e o registro para o correto relacionamento entre os modelos no mesmo procedimento clínico. A técnica é conveniente, de fácil manuseio e garante bons resultados clínicos (como pode ser observado no resultado final), e poucos ajustes foram necessários para a finalização do trabalho protético

The success of oral rehabilitation depends on the accuracy, both in impression and cast mounting on an articulator. When we have prosthesis in the free end edge, with large edentulous spaces, intercuspation becomes subject to errors and a stable and accurate record of the interocclusal relationship is recquired. The aim of this paper is to present a implant impression technique that, while splinting the cylinders to prepare the impression already makes the interocclusal record, getting the working model and the record for the correct relationship between the models in the same clinical step. The technique is convenient, easy to use and provides good clinical results as observed in final results, requiring only few adjustments for the completion of the prosthetic work

Comparative evaluation of condylar position in symptomatic (TMJ dysfunction) and asymptomatic individuals.

Context: The etiopathogenesis of temporomandibular joint (TMJ) disorders has been attributed to multiple factors and, while the importance of centric relation (CR) has been acknowledged in dental literature, the role of condylar position and CR-CO (CO-centric occlusion) discrepancy in TMJ dysfunction (TMD) has been a source of controversy. Aim: To establish the relationship between condyle position and TMD. Setting and Design: This was a case-control study to evaluate condylar displacement and interarch CR-CO discrepancy in symptomatic subjects (with TMD) and compare them with asymptomatic subjects. Materials and Methods: Forty subjects were screened for TMD based on Helkimo index and grouped into asymptomatic and symptomatic groups. CR was registered using the modified Roth power centric bite registration after neuromuscular deprogramming. Models thus mounted on an Advanced Dental Design (AD2) articulator were evaluated for interarch CR-CO discrepancy. The condylar position discrepancy was recorded on a device MCD (measured condylar deviation). Statistical Analysis: The Student's t test was used to test statistical significance. The paired t test and the unpaired t test were used for comparing results within and between the groups. Pearson correlation coefficient was used to find out the correlation between MCD measurements and dental three-dimensional (3D) model analysis measurements. The Chi-square test was used to evaluate the qualitative data. Results: The average vertical and horizontal condylar displacements were significantly greater in the symptomatic group than in the asymptomatic group. There were significant deviations at the level of the occlusion in both groups. Conclusion: Condyle position may play a significant role in the etiopathogenesis of TMJ disorders.

Single step approach to make diagnostic impressions of both the arches and face bow transfer: A novel technique.

Context: Mounting the maxillary and mandibular dentulous casts for Diagnostic purpose requires many steps (including making maxillary and mandibular impressions, face-bow transfer, and bite registration) or many appointments. A simple new technique of doing all of this together without compromising on the accuracy can save time over the conventional mounting procedure. Aim: To compare the accuracy of a new technique of a single-step diagnostic mounting procedure with that of the conventional diagnostic mounting procedure. Materials and Methods: Ten dentulous patients with the full complement of teeth and without any history of temporomandibular disorder and orthodontic treatment were selected for this study. A detachable metal triple tray to replace the fork part of the face bow fork that further could be attached to face bow was fabricated. Dual-arch impressions and face-bow transfer were made in these subjects using this modified triple tray. These mountings were compared with the ones done with the conventional mounting procedure. Five linear measurements (using stable reference points on the articulator and the cast) were made and the values obtained by both the methods were compared. Statistical Analysis: The Student's 't' test for statistical analysis was used in this study. Results: The measurement values obtained by the single-step method were almost similar to the ones obtained by the conventional method. The various mean measurements for the single step and conventional methods were 37.7 ± 6.8 and 38.5 ± 6.5 mm; 70.0 ± 4.4 and 70.1 ± 4.2 mm; 57.0 ± 4.9 and 57.3 ± 4.2 mm; 71.3 ± 4.5 and 71.0 ± 4.6 mm; and 58.7 ± 2.5 and 58.3 ± 2.3 mm; respectively. The differences between the values obtained by the conventional and single-step methods were not statistically significant. Conclusion: The single-step procedure of diagnostic mounting can be used as an alternative to the conventional method, without compromising the quality of mounting.

A comparative study to evaluate the discrepancy in condylar guidance values between two commercially available arcon and non-arcon articulators: A clinical study.

Aim: The purpose of this study was comparative evaluation of sagittal condylar values of arcon and non-arcon articulators with cephalometric readings and to determine the amount of discrepancy in sagittal condylar guidance values between arcon and non-arcon articulators using same protrusive record. Materials and Methods: Twenty subjects in the age group of 19-35 years, free from temporomandibular joint dysfunction, and occlusal disharmony, with healthy dentition participated in the study. Hanau H2 (non-arcon type) and Hanau Wide-Vue (arcon type) articulators were programmed for sagittal condylar guidance values using the same protrusive record made in polysiloxane bite registration material with edge to edge degree of protrusion. The resultant values for both the articulators on either side were compared with values obtained from tracing of digital lateral cephalogram using Kodak Dental imaging Window software 6.6.3.0-C program. The tabulated data were subjected to statistical analysis, ANOVA (Fishers 'F' test) for group comparison, Tukey's HSD test for inter-comparison, student's unpaired 't' test for intra-group comparison, and level of significance (P) was calculated using the same. Results: The mean sagittal condylar guidance values of the three different groups were found to be very highly significant (P=0.001) and highly significant (P=0.002) on the right and left sides respectively. There was a very highly significant difference (P=0.001) and highly significant difference (P=0.003) between the arcon and non-arcon group on the right and left side respectively. No significant difference was found between the arcon and cephalometric group (P=0.284 right, P=0.853 left) and a statistically significant difference was found between the non-arcon and cephalometric group (P=0.049 right, P=0.015 left). On intragroup comparison there was no statistically significant difference in sagittal condylar values on the right and left sides. Conclusion: The mean difference in the sagittal condylar guidance values obtained from non-arcon and arcon articulators shows a low level of reproducibility, and no significant difference found in mean sagittal condylar values obtained from arcon articulator and cephalometric tracings indicates replication of sagittal condylar guidance value from image of articular eminence.

Fabrication of fixed partial dentures using functionally generated path technique and double casting.

Harmonious occlusion is a critical requirement for successful oral rehabilitation. Conventional techniques of construction have been unsuccessful in producing a prosthesis that can be inserted without intraoral occlusal adjustment. This article discusses the use of functionally generated path technique with double casting to fabricate fixed partial dentures. The merits of this approach and the technique involved are discussed in detail.

A comparative study of inter-abutment distance of dies made from full arch dual-arch impression trays with those made from full arch stock trays: An in vitro study.

Objectives: The dual-arch impression technique is convenient in that it makes the required maxillary and mandibular impressions, as well as the inter-occlusal record in one procedure. The accuracy of inter-abutment distance in dies fabricated from dual-arch impression technique remains in question because there is little information available in the literature. Materials and Methods: This study was conducted to evaluate the accuracy of inter-abutment distance in dies obtained from full arch dual-arch trays with those obtained from full arch stock metal trays. Results and Conclusion: The metal dual-arch trays showed better accuracy followed by the plastic dual-arch and stock dentulous trays, respectively, though statistically insignificant. The pouring sequence did not have any effect on the inter-abutment distance statistically, though pouring the non-working side of the dual-arch impression first showed better accuracy.

Comparative study of dental arch width in plaster models, photocopies and digitized images

The aim of this study was to comparatively assess dental arch width, in the canine and molar regions, by means of direct measurements from plaster models, photocopies and digitized images of the models. The sample consisted of 130 pairs of plaster models, photocopies and digitized images of the models of white patients (n = 65), both genders, with Class I and Class II Division 1 malocclusions, treated by standard Edgewise mechanics and extraction of the four first premolars. Maxillary and mandibular intercanine and intermolar widths were measured by a calibrated examiner, prior to and after orthodontic treatment, using the three modes of reproduction of the dental arches. Dispersion of the data relative to pre- and posttreatment intra-arch linear measurements (mm) was represented as box plots. The three measuring methods were compared by one-way ANOVA for repeated measurements (á = 0.05). Initial / final mean values varied as follows: 33.94 to 34.29 mm / 34.49 to 34.66 mm (maxillary intercanine width); 26.23 to 26.26 mm / 26.77 to 26.84 mm (mandibular intercanine width); 49.55 to 49.66 mm / 47.28 to 47.45 mm (maxillary intermolar width) and 43.28 to 43.41 mm / 40.29 to 40.46 mm (mandibular intermolar width). There were no statistically significant differences between mean dental arch widths estimated by the three studied methods, prior to and after orthodontic treatment. It may be concluded that photocopies and digitized images of the plaster models provided reliable reproductions of the dental arches for obtaining transversal intra-arch measurements.

Development of an experimental optoelectronic device to study the amplitude of mandibular movements

This study aimed to present a wireless mandibular motion tracking device and optoelectronic data acquisition system developed to analyze the real-time spatial motion of the entire mandible during mouth opening and closing with no restriction of any movement. The procedures were divided into three phases: confection of a kinematic arch, dynamic digital video image acquisition, and image processing and analysis by using graphic computation. Four sequences of jaw opening/closing movements were recorded in lateral view: two from the maximum intercuspation (MIC) and the other two from a forced mandibular retruded position. Jaw motion was recorded by a digital video camera and processed as spatial coordinates corresponding to the position variation of the markers in the kinematic arch. The results showed that the method was capable of recording and processing the dynamics of the mandibular movements during jaw opening/closing using pixel-magnitude points. The mandible showed points with less displacement located near the temporomandibular joint during the opening/closing movements from the mandibular retruded position. When the jaw movements were recorded from MIC, these points were located near the mandibular foramen.

Avaliaçäo cefalométrica das relaçöes maxilomandibulares de portadores de fissura transforame incisivo unilateral (6-11 anos): estudo transversal / Cephalometric study of maxillomandibular relationship in unilateral cleft lip and palate patients (6 to 11 years): transversal study

Foi realizado estudo transversal cefalométrico em 120 portadores de fissura transforame incisivo unilateral (76 do sexo masculino e 44 do feminino) com 6 a 11 anos de idade, operados no Hospital de Pesquisa e Reabilitaçäo de Lesöes Lábio-Palatais, sem tratamento ortodôntico, com objetivo de estudar suas relaçöes maxilomandibulares. A análise das 7 grandezas cefalométricas (SNA, SNB, ANB, SN.Gn, SN.GoGn, IMPA e 1.Pp) e 3 lineares (Co-A, Co-Gn e AFAI) foi realizada com amostra dividida em grupos etários (6 - 8 e 9 - 11), para os sexos masculino e feminino, e os dados obtidos foram comparados com valores de amostras de crianças brasileiras näo fissuradas, com oclusäo normal, observando-se as seguintes conclusöes: A maxila e a mandíbula apresentaram-se retropostas e de menor comprimento desde o início da dentura mista; A relaçäo intermaxilar foi positiva; Houve tendência de crescimento no sentido vertical; Existiu retroincliniçäo de incisivos superiores e inferiores; A altura facial ântero-inferior apresentou-se aumentada desde o início da dentadura mista, porém com significância estatística somente para o sexo masculino dos 6 aos 8 anos; As diferenças estatiticamente significativas encontradas para algumas grandezas, entre os sexos e entre as faixas etárias, constituiram eventos casuais, tendo os grupos demonstrado crescimento com comportamento semelhante

El ángulo desoclusivo posterior y la curva de spee en pacientes con sobremordida vertical mayor o igual al 50 por ciento / Different measures in patients with vertical overoclusion greater than 50 por ciento

En esta investigación, se establece el valor promedio del ángulo desoclusivo posterior en pacientes con una sobremordida vertical mayor o igual al 50 por ciento, y se determina, el tipo de relación existente entre el ángulo desoclusivo posterior y la sobremordida vertical; y entre el ángulo desoclusivo posterior y la curva de Spee. Se ecogieron 18 pacientes, a los cuales se les realizó Pantografía Sagital (whip-Mix 2100), y se tomaron impresiones para modelos con el fin de medir la sobremordida vertical y la curva de Spee. Los valores promedio fueron: 1- Angulo desoclusivo posterior 47.53º. 2- Sobremordida vertical 71 por ciento. 2- Curva de Spee 2.542. se determinó, que aunque existe tendencia a una relación directamente proporcional entre el ángulo desoclusivo posterior y la sobremordida vertical e inversamente porporcional ente el ángulo desoclusivo posterior y la curva de Spee, el Indice de Correlación, de 0.168427 para el primer caso y de -0.17381 para el segundo caso, indica que esta relación no es estadísticamente significativa. Se sugiere entonces, y para establecer un punto de partida en el diagnóstico y plan de tratamiento, realizar esta misma investigación, pero con una muestra mayor y con los parámetros de normalidad funcional y oclusal, teniendo en cuenta todas las variables que modifican el Componente Anterior de Descolusión