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.

Golden proportions as predictors of attractiveness and malocclusion.

Objective: In recent years, the golden proportions have been evaluated by various researchers in the general population and orthodontic patients to establish their correlation with facial attractiveness and esthetics, but with conflicting results. The present study aimed to analyze the frontal facial golden proportions for three groups of young adult females, an attractive group, and two malocclusion groups. Our null hypothesis stated that the golden proportions of attractive females were analogous with or closer to the golden number than those with an established malocclusion. Materials and Methods: Frontal facial photographs of 80 female dental students were scored for facial attractiveness by 10 dental specialists. Thirty females with scores greater than the median score of 48 formed the attractive group. Thirteen females with Class I malocclusion and 15 females with Class II division 1 malocclusion formed the two malocclusion groups. Ten landmarks and 19 golden proportions were calculated for all subjects. One‑way ANOVA and unpaired Student’s t‑test was used to analyze the differences in golden proportions between the attractive and malocclusion groups. Results: Significant differences were observed for 10 proportions (P < 0.04 to < 0.0001). Five vertical proportions showed significant differences in both subgroups; Attractive versus Class I and Attractive versus Class II division 1; while one vertical and all transverse proportions showed significant differences only in Attractive versus Class II division 1 subgroup. The average values of these proportions varied both toward and away from the golden number for both attractive and malocclusion groups. Conclusion: Facial proportions of the attractive females were significantly different from those with malocclusion, but did not show a constant trend of being closer to the golden number. Furthermore, the golden proportions were not analogous with the facial esthetics of the attractive females.

Study of face pleasantness using facial analysis in standardized frontal photographs

OBJECTIVE: The purpose of this research was to check if the numeric facial analysis can determine facial attractiveness. METHOD: The sample consisted of frontal and lateral standard facial photographs, in natural head position, of 85 Brazilian Caucasian women, without facial plastic surgery report. The sample mean age was 23 years and 9 months. A group of 5 orthodontists, 5 layman and 5 plastic artists classified the photographs according to their own attractiveness graduation in: pleasant, acceptable and not pleasant. The numeric facial analysis was then performed using a computerized method. Linear, proportional and angular measurements were compared among groups. RESULTS: According subjective analysis the sample was consisted of 18.8% of pleasant, 70.6% of acceptable and 10.6% of not pleasant. In most measurements there were no differences among groups. Just in three of them significant statistical difference was observed and in two of them the comparison value was within decision limit. All the differences found were related to the lower third of the face and to facial pattern. CONCLUSION: On the present research, the numeric facial analysis, by itself, was not capable of detecting facial attractiveness, considering that beauty judgment seems to be very personal.

OBJETIVO: esse estudo foi desenvolvido com o propósito de verificar se a análise facial numérica realizada em fotografias frontais é sensível em detectar a atratividade da face. MÉTODOS: a amostra foi composta por fotografias faciais padronizadas, frontais e laterais, em posição natural da cabeça, de 85 mulheres brasileiras, leucodermas, com idades entre 18 e 30 anos, sem histórico de cirurgia plástica facial. A idade média da amostra foi de 23 anos e 9 meses. As fotografias foram classificadas de acordo com o grau de atratividade da face por uma banca composta de cinco especialistas em Ortodontia, cinco leigos e cinco artistas plásticos. A partir dessa classificação, os indivíduos foram divididos em três grupos: esteticamente agradáveis, esteticamente aceitáveis e esteticamente desagradáveis. Em seguida, foram realizados os traçados fotométricos por meio computadorizado. As médias das variáveis lineares, proporcionais e angulares propostas foram comparadas estatisticamente entre os grupos. RESULTADOS: pela análise subjetiva, 18,8% da amostra foram classificados como esteticamente desagradáveis, 70,6% como esteticamente aceitáveis e 10,6% como esteticamente agradáveis. Na maioria das variáveis, não observou-se diferenças entre os grupos. Em apenas três delas houve diferenças estatisticamente significativas. Todas as diferenças encontradas relacionaram-se ao terço inferior da face e ao padrão facial. CONCLUSÃO: no presente estudo, a análise facial numérica utilizada isoladamente não foi sensível na detecção de padrões de atratividade, já que os critérios de beleza parecem ser altamente subjetivos.

The frontal characteristics of esthetic lips and lips after anterior segmental osteotomy in Korean females / 대한치과교정학회지

OBJECTIVE: The aim of this study was to determine firstly the characteristics of esthetic lips in Korean females and secondly to measure the changes of the lips before and after anterior segmental osteotomy in bimaxillary protruded patients. METHODS: Samples consisted of 30 models and 26 nonmodels, and 10 patients who had received anterior segmental osteotomy. Twelve linear measurements, 5 angular measurements, and the lip perimeter and area were measured. These results were compared for each group using unpaired and paired t-tests. RESULTS: Full face width, nose to chin, upper vermilion height and angle, lateral heights at the point of the tips of Cupid's bow, central bow angle, and the lower lip to chin lengths were significantly greater in nonmodels than in models. However, overall lip width, lower vermilion height and angle, tip-to-tip of Cupid's bow lip perimeter, and lower vermilion area were greater in models than in nonmodels. Comparison of before and after anterior segmental osteotomy revealed that the values for the upper vermilion and lateral heights, the angle to Cupid's bow tip lengths, and upper vermilion area of post-operative patients had become similar to those of Korean female models. Our findings demonstrated that Korean female models have a fuller lower vermilion & thinner upper vermilion compared with nonmodel controls, as determined by the vermilion heights, angles, and areas. CONCLUSIONS: It will be helpful for clinicians to use these measurements as guidelines for improving patients' facial esthetics.

Level of perception of changed lip protrusion and asymmetry of the lower facial height / 대한치과교정학회지

OBJECTIVE: While one of the most prevailing motivations for seeking orthodontic treatment is to achieve good facial esthetics, understanding the level of a person's perception to the changes that have occurred on the face after orthodontic treatment is critical to the process of orthodontic diagnosis and treatment planning. METHODS: 40 students attending art school participated in determining the level of their perception of changed lip position and facial asymmetry. Computer-graphic frontal face and facial profile photographs with balanced proportions were used to evaluate the level of a participant's perception of the changes in facial asymmetry and in lip position. RESULTS: Change of lip position over 2 mm and over a 3 mm change of facial asymmetry was perceived significantly. CONCLUSION: The results indicated that at least a 2 mm change of lip position was needed to be perceived after orthodontic treatment. The level of perception of the change in facial asymmetry was lower than that of the change in lip position. Information about facial changes given prior to the evaluation enhanced the level of perception.

Level of perception related to changes in lower facial height / 대한치과교정학회지

Understanding the level of a person's perception of changes that have occurred on the face after orthodontic treatment is critical to the process of orthodontic diagnosis and treatment planning. The purpose of this study was to determine the level of perception of profile and frontal changes in lower facial height. Forty students attending art school participated in a study evaluating the level of a participant's perception of changes in the lower facial height. Participants compared computer-graphic frontal and profile photographs with balanced proportions and photograph simulations of 1, 2, 3, and 4 mm changes in lower facial height from stomion to the chin. At least a 2 mm change in lower facial height for the profile view and 3 mm in the frontal view was needed to be perceived after orthodontic treatment. The level of a person's perception of the change in lower facial height was more sensitive in the profile view than in the frontal view, and information about facial changes given prior to evaluation enhanced the level of perception.

A study on the characteristics of attractive profiles of Korean young women to orthodontists / 대한치과교정학회지

The perception of facial esthetics is critically important to orthodontists. A viewpoint to facial esthetics is influenced by various factors and dependent on the perception of observer. The purpose of this study was to examine the differences regarding esthetic viewpoints among orthodontists, to identify attractive profiles preferred to orthodontists and to present the characteristic aspects of attractive profiles upon the degree of facial convexity. 35 persons whose faces were judged as attractive one by 5 orthodontists were selected out of 133 young Korean women. Soft tissue profiles identified as a good-profile group were measured and analyzed. And then according to the facial convexity, good-profile group was subdivided to convex (G-Sn-Pg9degrees) and straight (G-Sn-Pg<9degrees) groups for the purpose of this study. There were statistically no significant differences regarding esthetic viewpoints among 5 orthodontists(p<0.05), even if there exists prevailing concept that the standard for facial esthetics is substantially subjective. N-Pg-Sn and N-Pg-Pn, measured for determining anteroposterior relationship of midfacial convexity, showed significant differences statistically between 2 subgroups (p<0.05) while nasolabial angle, labiomental angle, and vertical measurements didnt show statistically significant difference between 2 subgroups (p<0.05). And all the measurements related to lip position, H-angle, Ls to E line, Li to E line and Pg to Sn perp., had statistically significant differences between 2 subgroups (p<0.05). The results indicate that the attractive facial profile has different characteristics to be recognized as a good facial pattern, which depend strongly on anteroposterior position of nose, upper and lower lips, and chin.

Relationship between changes of facial soft tissue and hard tissue profile in correction of children's mandible retruding by functional appliance / 中华医学美学美容杂志

Objective To evaluate the changes of soft tissue and hard tissue in the correction of Class II division 1 malocclusion by functional appliance, and to investigate the correlation between these changes and the mechanism underlying the soft tissue profile changes. Methods A total of 32 cases of developing class II division 1 malocclusion were selected. They were in the spurt or pre-spurt phase of growth and development and treated with functional appliance, the molar relationship was corrected to either Class I or overcorrected Class I occlusal relationship. Soft tissue and hard tissue variables on the cephalograms were selected and analyzed. Firstly, paired t-tests were performed to compare the changes between before and after-treatment. Secondly, those variables that had statistically significant differences were selected and analyzed with the Pearson coefficient of correlation (r) between soft tissue and hard tissue changes. Results All variables had statistically significant differences between before and after treatment except for soft tissue facial angle and basic upper lip thickness, mandible plane angle and position of basic upper bone; Correlations between soft tissue and hard tissue changes were as follows: height of lower lip to Me' and S-Go (r=0.54); soft tissue chin thick and N-ANS (r=0.55); height of upper lip and ii/OLp (r=0.52); inferior sulcus to H-line and ii/OLp (r=0.60), pg/OLp, saggital relationship between upper-and lower-jaw (ss/OLp-pg/OLp) (r=0.47). Conclusion The changes of soft tissues profile results from the change of lower incisors' position, mandible' moving forward and its subsequent changes of facial heights and saggital relationship between upper-and lower-jaws.

A Clinical Study of the Nasal Morphologic Changes following LeFortI Osteotomy

The facial esthetics are much affected by nasal changes due to especially its central position in relation to facial outline and so appropriately evaluated should be the functional and esthetic aspects of the nose associated with the facial appearance. Generally, a maxillary surgical movement is known to induce the changes of nasolabial morphology secondary to the skeletal repositioning accompanied by muscular retraction. These changes can be desirable or undesirable to individuals according to the direction and amount of maxillary repositioning. We investigated the surgical changes of bony maxilla and its effects to nasal morphology through the analysis of the lateral cephalogram in the Le Fort I osteotomy. Subjects were 10 patients(male 2, female 8, mean age 22.3 years) and cephalograms were obtained 2 weeks before surgery(T1) and 6 months after surgery(T2). The surgical maxillary movement was identified through the horizontal and vertical repositioning of point A. Soft-tissue analysis of the nasal profile was performed employing two angles: nasal tip projection(NTP), columellar angle(CA). Also, alar base width(ABW) was assessed directly on the patients with a slide gauge. The results were as follows: 1. Both anterior and superior movement above 2mm of maxilla rotated up nasal tip above 1mm. Either anterior or superior movement above 2mm of maxilla made prediction of the amount & direction of NTP changes difficult. Especially, a correlation between horizontal movement of maxilla and NTP rotated-up was P<0.01. 2. Both much highly anterior and superior movement of maxilla is accompanied by more CA increase than either highly. Especially, the correlation between horizontal movement of maxilla and CA change was P<0.05. 3. Anterior and/or superior movement of maxilla was accompanied by the unpredictable ABW widening. 4. The amount of changes of NTP, CA, and ABW is not in direct proportion to amout of anterior and/or superior movement of maxilla. 5. Nasal morphologic changes following Le Fort I osteotomy are affacted by not merely bony repositioning but other multiple factors.

Lip profile changes after orthodontic tooth movement in female adult with bimaxillary protrusion / 대한치과교정학회지

Facial esthetics is one of the most important goal of the orthodontic treatment and main concern of many patients. Facial esthetics should be considered in orthodontic diagnosis and treatment planning. Prediction of soft tissue profile changes after orthodontic tooth movement should be considered as well. The purpose of this study was to find out the effect of orthodontic treatment on lip profile in adult patient. The pre and post treatment cephalometric reontgenograms of 87 female adult with bimaxillary protrusion were used to analyze lip profile change. All subjects were treated with four bicuspids extraction. Obtained results were as follows: 1. Lip thickness changes after incisor retraction showed different patterns according to areas of the lip. The thickness of the red lip area showed 2.78 mm increase in average. In contrast the thickness of the cutaneous area showed 0.65 - 0.7 mm decrease according to the different cutaneous areas. 2. The length of the red lip area decreased(1.3mm) after incisor retraction. 3. The length of the cutaneous lip area increased(2.9mm) after incisor retraction.