The effect of anatomical variations of the sinonasal region on maxillary sinus volume and dimensions: a three-dimensional study / Efeito das variações anatômicas da região nasossinusal sobre o volume e as dimensões do seio maxilar: um estudo tridimensional

Abstract Introduction Anatomical variations in the sinonasal region are remarkably common and these variations may have an impact on maxillary sinus development due to their close anatomical adjacency. Objective The aim of this study was to investigate the effect of anatomical variations of the sinonasal region on the width, height, length, and volume of the maxillary sinus. Methods Cone beam computed tomography records of 120 patients were evaluated. Nasal septum deviation angle was measured for each patient and patients were divided into three groups as mild, moderate, and severe. Sinonasal variations such as nasal septum deviation direction, septal spur, concha bullosa, uncinate process pneumatization, middle concha hypertrophy, inferior concha hypertrophy, paradoxical middle concha and presence of septa in the maxillary sinus were registered. Cone beam computed tomography images were transferred to the SimPlant software thus right and left maxillary sinus volumes and dimensions were measured separately. Results There was a negative and statistically significant relationship between age and left maxillary sinus width (p= 0.015). The relationships between gender and maxillary sinus volumes and dimensions were statistically significant (p< 0.05). Although there were significant relationships between the nasal septum deviation severity, middle concha hypertrophy, inferior concha hypertrophy, paradoxical middle concha, and presence of septa and maxillary sinus dimensions; there was no significant relationship between septal spur, nasal septum deviation direction, concha bullosa, uncinate process pneumatization, and maxillary sinus dimensions. No statistically significant relationship could be determined between maxillary sinus volume and anatomical variations of the sinonasal region. Conclusion According to our findings, while certain the variations were found to affect the sinus dimensions; none of the variations was found to be related to the maxillary sinus volume.

Resumo Introdução As variações anatômicas na região nasossinusal são extremamente comuns e essas variações podem ter um impacto no desenvolvimento do seio maxilar, devido à proximidade anatômica. Objetivo Investigar o efeito das variações anatômicas da região nasossinusal na largura, altura, comprimento e volume do seio maxilar. Método Foram avaliados registros de tomografia computadorizada de feixe cônico de 120 pacientes. O ângulo de desvio do septo nasal foi medido para cada paciente e os pacientes foram divididos em três grupos: leve, moderado e grave. Foram observadas variações nasossinusais, como direção do desvio do septo nasal, esporão septal, concha bolhosa, pneumatização do processo uncinado, hipertrofia da concha média, hipertrofia da concha inferior, concha média paradoxal e presença de septos no seio maxilar. Imagens de tomografia computadorizada de feixe cônico foram transferidas para o software SimPlant e, portanto, os volumes e dimensões dos seios maxilares direito e esquerdo foram medidos separadamente. Resultados Houve uma relação negativa e estatisticamente significante entre a idade e a largura do seio maxilar esquerdo (p = 0,015). As relações entre gênero e volumes e dimensões do seio maxilar foram estatisticamente significantes (p < 0,05). Embora houvesse relações significativas entre a gravidade do desvio do septo nasal, hipertrofia da concha média, hipertrofia da concha inferior, concha média paradoxal e presença de septos e dimensões do seio maxilar, não houve relação significativa entre esporão septal, direção do desvio do septo nasal, concha bolhosa, pneumatização do processo uncinado e dimensões do seio maxilar. Nenhuma relação estatisticamente significante pôde ser determinada entre o volume do seio maxilar e as variações anatômicas da região nasossinusal. Conclusão De acordo com nossos achados, embora certas variações tenham afetado as dimensões sinusais, nenhuma das variações foi efetivamente relacionada ao volume do seio maxilar.

Comparison of radiographic and tomographic evaluations for measurement of the Canal Flare Index in dogs / [Comparação entre avaliação radiográfica e tomográfica para mensuração do Canal Flare Index em cães]

The outcome of total hip arthroplasty (THA) in dogs is directly related to surgical planning. Templating of radiographs prior to THA should help the surgeon anticipate prosthesis size and femoral shape allowing canal fill of the proximal metaphysis by the implant ensuring primary stable fixation. The canal flare index (CFI) obtained from radiograph has been used as a measure of risk of complications for the technique in human beings and dogs. However, standard radiographs only provide limited data for the selection of cementless prostheses and the assessment of their fit within the femoral canal, due to factors like radiographic magnification and femoral rotation. Therefore, three-dimensional evaluation based on computed tomography (CT) may be a better tool for CFI measurement. The aim of this study was to compare anatomical measurement with CFI values obtained from craniocaudal radiography and CT. Craniocaudal radiographs using a horizontal radiographic beam (CR), CT, and anatomical macroscopic measurements (A) were obtained from 45 femurs from 23 canine cadavers. The differences between the values of CFI obtained from radiograph (CFI-R), computed tomography on transverse (CFI- TT) and longitudinal axis (CFI-TL) compared to the CFI obtained from macroscopic measurements - gold standard - (CFI-A), and 95% limits of agreement (LOA) between the values, were evaluated by the Bland-Altman method. Dimensions obtained from CT techniques had a greatest mean difference from anatomical and CFI values were also different (P=0.032). Under the experimental conditions, the craniocaudal radiograph, provided the most accurate measurement of the CFI (mean difference: 0.087 ± 0.42).(AU)

O resultado da artroplastia total do quadril (ATQ) em cães está diretamente relacionado ao planejamento cirúrgico. O templating radiográfico pré-operatório da ATQ deve ajudar o cirurgião a prever o tamanho da prótese e o formato do fêmur, o que permitirá um preenchimento ideal da metáfise proximal pelo implante, garantindo, assim, fixação primária estável. O índice de alargamento do canal (Canal Flare Index - CFI) obtido em radiografias tem sido utilizado como fator de risco de complicações para a técnica em humanos e cães. No entanto, as radiografias podem fornecer apenas dados limitados para a seleção de próteses não cimentadas e a avaliação do seu encaixe no canal femoral, devido a fatores como ampliação radiográfica e rotação femoral. Portanto, a avaliação tridimensional baseada na tomografia computadorizada (TC) pode ser uma ferramenta vantajosa para a mensuração do CFI. O objetivo deste estudo foi comparar a medida anatômica com os valores de CFI obtidos na radiografia craniocaudal e na TC. Radiografias craniocaudais utilizando feixe radiográfico horizontal (CR), tomografia computadorizada e medidas macroscópicas anatômicas (A) foram obtidas de 45 fêmures de 23 cadáveres caninos. As diferenças entre os valores de CFI obtidos na radiografia (CFI-R), na tomografia computadorizada no eixo transversal (CFI-TT) e no eixo longitudinal (CFI-TL), em comparação com os valores de CFI obtidos nas medições macroscópicas - padrão-ouro - (CFI-A) e os limites de concordância de 95% (LOA) entre os valores, foram avaliadas pelo método de Bland-Altman. As dimensões obtidas pelas técnicas de TC apresentaram maior diferença média dos valores anatômicos, e as do CFI também foram diferentes (P=0,032). Nas condições experimentais, a radiografia craniocaudal forneceu a medida mais precisa do CFI (diferença média: 0,087 ± 0,42) para representar o padrão-ouro deste estudo.(AU)

Three-dimensional morphological analysis of the palate of mouth-breathing children in mixed dentition / 华西口腔医学杂志

OBJECTIVE@#To study the effects of mouth-breathing on maxillary arch development by comparing the palatal morphology of mouth- and nose-breathing children in mixed dentition.@*METHODS@#Children in mixed dentition were enrolled and categorized into mouth-breathing (test group) and nose-breathing groups (control group) according to their breathing patterns. Children's plaster models were scanned with 3D laser scanner, and the 3D data were reconstructed and measured using Minics 15.0 and Geomagic 12.0 software. Measurement data (inter-molar width, palatal height, palatal volume, and palatal surface area) of the two groups were compared, and the correlation among the four measurement items was analyzed.@*RESULTS@#The participants were 73 children (37 in test group and 36 in control group) with a mean age of (8.63±0.78) years old. The test group had significantly smaller inter-molar width, palatal volume, and palatal surface area but significantly higher palatal height than the control group (P<0.05). Inter-molar width and palatal volume were positively correlated with the palatal surface area in the test group (P<0.05). Inter-molar width and palatal height were positively correlated with the palatal surface area in the control group (P<0.01).@*CONCLUSIONS@#Mouth-breathing children have significantly reduced inter-molar width, palatal volume, and surface, and substantially increased palatal height, leading to different developmental patterns of the palatal morphology.

Comparison of the accuracy of intraoral scanner by three-dimensional analysis in single and 3-unit bridge abutment model: In vitro study / 대한치과보철학회지

PURPOSE: The purpose of this study was to evaluate the accuracy of three types of intraoral scanners and the accuracy of the single abutment and bridge abutment model. MATERIALS AND METHODS: In this study, a single abutment, and a bridge abutment with missing first molar was fabricated and set as the reference model. The reference model was scanned with an industrial three-dimensional scanner and set as reference scan data. The reference model was scanned five times using the three intraoral scanners (CS3600, CS3500, and EZIS PO). This was set as the evaluation scan data. In the three-dimensional analysis (Geomagic control X), the divided abutment region was selected and analyzed to verify the scan accuracy of the abutment. Statistical analysis was performed using SPSS software (α = .05). The accuracy of intraoral scanners was compared using the Kruskal-Wallis test and post-test was performed using the Pairwise test. The accuracy difference between the single abutment model and the bridge abutment model was analyzed by the Mann-Whitney U test. RESULTS: The accuracy according to the intraoral scanner was significantly different (P < .05). The trueness of the single abutment model and the bridge abutment model showed a statistically significant difference and showed better trueness in the single abutment (P < .05). There was no significant difference in the precision (P = .616). CONCLUSION: As a result of comparing the accuracy of single and bridge abutments, the error of abutment scan increased with increasing scan area, and the accuracy of bridge abutment model was clinically acceptable in three types of intraoral scanners.

Influence of beverage type and ingestion time on tooth corrosion / 대한치과재료학회지

This study was conducted to analyze the effects of beverages on tooth corrosion by selecting drinks that are enjoyed by modern people. Drinks were selected for carbonated beverages (Coca Cola), energy drinks (Red Bull), orange juice, beer (Hite) and water (Evian). Bovine tooth was immersed for 1 hour, 24 hours and 48 hours. The root mean square (RMS) values were obtained by scanning the bovine tooth at pre-immersion and immersion time after impression making. Two-way ANOVA, one-way ANOVA, and Tukey-test were used to compare differences between groups (α=0.05). The RMS value tended to increase with longer immersion times in all beverages, and there was a significant difference (p < 0.05) between before immersion-1hr and before immersion-48 hr. The mean of RMS according to the type of beverage was significantly different and there was a significant difference according to the change of immersion time (p < 0.05). In order to prevent tooth corrosion, it is necessary to change the method of ingestion or to reduce the time of ingestion.

Morphological classification of mandible posterior region based on cone beam CT images / 中华口腔医学杂志

Objective@#To classify the morphology of mandible posterior region and provide reference for the planning of dental implantation.@*Methods@#Cone beam CT data of 208 patients were collected. The CT data were imported into CS 3D imaging V3 software and then the morphology of mandible posterior region were analyzed. The types of premolar and molar mandible cross-section morphology were recorded, classified and analyzed.@*Results@#The results showed that type A (vertical type) (79%-96%) was the most common in the premolars, whereas type B (inclined type) (36%-37%) and type C (lingual inverted concave) (30%-54%) were the most common types in the molars, followed type D (absorption severe type) (2%-5%). There was a statistically significant differences in tooth positions (P<0.001), tooth deficiency aspect (P<0.001) and different side (P=0.013), different age (P<0.001), and different gender (P=0.007).@*Conclusions@#Using cone beam CT to determine the morphology of mandible may be a reference for the planning of dental implantation.

A study on the machining accuracy of dental digital method focusing on dental inlay

PURPOSE: The purpose of this study was to compare the cutting method and the lamination method to investigate whether the CAD data of the proposed inlay shape are machined correctly. MATERIALS AND METHODS: The Mesial-Occlusal shape of the inlay was modeled by changing the stereolithography (STL). Each group used SLS (metal powder) or SLA (photocurable resin) in the additive method, and wax or zirconia in the subtractive method (n=10 per group, total n=40). Three-dimensional (3D) analysis program (Geomagic Control X inspection software; 3D systems) was used for the alignment and analysis. The root mean square (RMS) in the 2D plane state was measured within 50 µm radius of eight comparison measuring points (CMP). Differences were analyzed using one-way analysis of variance and post-hoc Tukey's test were used (α=.05). RESULTS: There was a significant difference in RMS only in SLA and SLS of 2D section (P < .05). In CMP mean, CMP 4 (−5.3±46.7 µm) had a value closest to 0, while CMP 6 (20.1±42.4 µm) and CMP 1 (−89.2±61.4 µm) had the greatest positive value and the greatest negative value, respectively. CONCLUSION: Since the errors obtained from the study do not exceed the clinically acceptable values, the lamination method and the cutting method can be used clinically.

Accuracy and reproducibility of 3D digital tooth preparations made by gypsum materials of various colors

PURPOSE: The study aimed to identify the accuracy and reproducibility of preparations made by gypsum materials of various colors using quantitative and semi-quantitative three-dimensional (3D) approach. MATERIALS AND METHODS: A titanium maxillary first molar preparation was created as reference dataset (REF). Silicone impressions were duplicated from REF and randomized into 6 groups (n=8). Gypsum preparations were formed and grouped according to the color of gypsum materials, and light-scanned to obtain prepared datasets (PRE). Then, in terms of accuracy, PRE were superimposed on REF using the best-fit-algorithm and PRE underwent intragroup pairwise best-fit alignment for assessing reproducibility. Root mean square deviation (RMSD) and degrees of similarity (DS) were computed and analyzed with SPSS 20.0 statistical software (α=.05). RESULTS: In terms of accuracy, PREs in 3D directions were increased in the 6 color groups (from 19.38 to 20.88 µm), of which the marginal and internal variations ranged 51.36 – 58.26 µm and 18.33 – 20.04 µm, respectively. On the other hand, RMSD value and DS-scores did not show significant differences among groups. Regarding reproducibility, both RMSD and DS-scores showed statistically significant differences among groups, while RMSD values of the 6 color groups were less than 5 µm, of which blue color group was the smallest (3.27 ± 0.24 µm) and white color group was the largest (4.24 ± 0.36 µm). These results were consistent with the DS data. CONCLUSION: The 3D volume of the PREs was predisposed towards an increase during digitalization, which was unaffected by gypsum color. Furthermore, the reproducibility of digitalizing scanning differed negligibly among different gypsum colors, especially in comparison to clinically observed discrepancies.

Accuracy of several implant bite registration techniques: an in-vitro pilot study

PURPOSE: This study evaluated the accuracies of different bite registration techniques for implant-fixed prostheses using three dimensional file analysis. MATERIALS AND METHODS: Implant fixtures were placed on the mandibular right second premolar, and the first and second molar in a polyurethane model. Aluwax (A), Pattern Resin (P), and Blu-Mousse (B) were used as the bite registration materials on the healing abutments (H) or temporary abutments (T). The groups were classified into HA, HP, HB, TA, TP, and TB according to each combination. The group using the bite impression coping was the BC group; impression taking and bite registration were performed simultaneously. After impression and bite taking, the scan bodies were connected to the lab analogs of the casts. These casts were scanned using a model scanner. The distances between two reference points in three-dimensional files were measured in each group. One-way ANOVA and Duncan's test were used at the 5% significance level. RESULTS: The smallest distance discrepancy was observed in the TB group using the temporary abutments. The Blu-Mousse and HP groups showed the largest distance discrepancy. The TB and BC groups showed a lower distance discrepancy than the HP group (P=.001), and there was no significant difference between the groups using the temporary abutments and healing abutments (P>.05). CONCLUSION: Although this study has limitations as an in-vitro investigation, the groups using the temporary abutments to hold the Blu-Mousse record and bite impression coping showed greater accuracy than the group using the healing abutments to hold the pattern resin record.

Preliminary three-dimensional analysis of tooth movement and arch dimension change of the maxillary dentition in Class II division 1 malocclusion treated with first premolar extraction: conventional anchorage vs. mini-implant anchorage / 대한치과교정학회지

OBJECTIVE: This study aimed to compare the effects of conventional and orthodontic mini-implant (OMI) anchorage on tooth movement and arch-dimension changes in the maxillary dentition in Class II division 1 (CII div.1) patients. METHODS: CII div.1 patients treated with extraction of the maxillary first and mandibular second premolars and sliding mechanics were allotted to conventional anchorage group (CA, n = 12) or OMI anchorage group (OA, n = 12). Pre- and post-treatment three-dimensional virtual maxillary models were superimposed using the best-fit method. Linear, angular, and arch-dimension variables were measured with software program. Mann-Whitney U-test and Wilcoxon signed-rank test were performed for statistical analysis. RESULTS: Compared to the CA group, the OMI group showed more backward movement of the maxillary central and lateral incisors and canine (MXCI, MXLI, MXC, respectively; 1.6 mm, p < 0.001; 0.9 mm, p < 0.05; 1.2 mm, p < 0.001); more intrusion of the MXCI and MXC (1.3 mm, 0.5 mm, all p < 0.01); less forward movement of the maxillary second premolar, first, and second molars (MXP2, MXM1, MXM2, respectively; all 1.0 mm, all p < 0.05); less contraction of the MXP2 and MXM1 (0.7 mm, p < 0.05; 0.9 mm, p < 0.001); less mesial-in rotation of the MXM1 and MXM2 (2.6degrees, 2.5degrees, all p < 0.05); and less decrease of the inter-MXP2, MXM1, and MXM2 widths (1.8 mm, 1.5 mm, 2.0 mm, all p < 0.05). CONCLUSIONS: In treatment of CII div.1 malocclusion, OA provided better anchorage and less arch-dimension change in the maxillary posterior teeth than CA during en-masse retraction of the maxillary anterior teeth.

New Statistical Method to Analyze Three-Dimensional Landmark Configurations Obtained with Cone-Beam CT: Basic Features and Clinical Application for Rapid Maxillary Expansion

OBJECTIVE: To describe a statistical method of three-dimensional landmark configuration data and apply it to an orthodontic data set comparing two types of rapid maxillary expansion (RME) treatments. MATERIALS AND METHODS: Landmark configurations obtained from cone beam CT scans were used to represent patients in two types (please describe what were two types) of RME groups and a control group over four time points. A method using tools from persistent homology and dimensionality reduction is presented and used to identify variability between the subjects. RESULTS: The analysis was in agreement with previous results using conventional methods, which found significant differences between treatment groups and the control, but no distinction between the types of treatment. Additionally, it was found that second molar eruption varied considerably between the subjects, and this has not been evaluated in previous analyses. CONCLUSION: This method of analysis allows entire configurations to be considered as a whole, and does not require specific inter-landmark distances or angles to be selected. Sources of variability present themselves, without having to be individually sought after. This method is suggested as an additional tool for the analysis of landmark configuration data.

The ovary of Lagostomus maximus (Mammalia, Rodentia): an analysis by confocal microscopy

Lagostomus maximus is a notable mammalian model for reproductive studies. Females have an extremely high ovulation rate, which is due to down-regulation of the follicular apoptosis pathway, which ensures a large pool of developing follicles. This large pool is supported by the convoluted anatomy of the mature ovary, whose germinal tissue is found in irregularly curved ridges throughout the cortex. Medullary tissue is restricted to a minimum. Lyso Tracker Red reconstruction under confocal laser scanning microscopy was used to recognize and measure all follicular stages from primordial to antral. Unlike most mammals in which early primordial follicles are just found in fetal life, the adult ovary shows regions packed with early primordial follicles. Follicle size ranged from 24 to 316 µm. We discuss the relationships of L. maximus follicles size with regard to other species of mammals and propose that the physiology of the adult viscacha ovary obeys to a neoteny process in the evolution of this species.

Nystagmus as a Sign of Labyrinthine Disorders: Three-Dimensional Analysis of Nystagmus

In order to diagnose the pathological condition of vertiginous patients, a detailed observation of nystagmus in addition to examination of body equilibrium and other neurotological tests are essential. How to precisely record the eye movements is one of the goals of the researchers and clinicians who are interested in the analysis of eye movements for a long time. For considering that, one has to think about the optimal method for recording eye movements. In this review, the author introduced a new method, that is, an analysis of vestibular induced eye movements in three-dimensions and discussed the advantages and limitations of this method.

Análise cinemática tridimensional do movimento de eqüinos em esteira rolante / Three-dimensional cinematic analysis of the horse movement in treadmill

Adaptou-se uma metodologia utilizada no estudo do movimento humano para analisar o movimento de eqüinos em esteira rolante de alto desempenho, construindo-se um sistema de calibração utilizando-se um teodolito eletrônico de alta precisão e calibradores que demarcavam o espaço ocupado pelo animal. Dessa forma, foram obtidas as coordenadas espaciais dos marcadores presentes nos calibradores, compondo o arquivo de calibração. Duas câmeras de vídeo (60Hz) foram posicionadas em vista lateral esquerda, distantes 5m da manta de rolagem da esteira a 1,8m de altura. As imagens foram enquadradas utilizando-se um monitor de vídeo. Para a validação do método, um membro da equipe movimentou, no espaço calibrado, uma haste rígida com marcadores fixados nas suas extremidades, distantes um do outro 43,8cm. Para a análise das imagens, utilizou-se o programa Dvideow, desenvolvido pelo Laboratório de Instrumentação para Biomecânica - UNICAMP. Após a reconstrução tridimensional das imagens utilizou-se um programa matemático para o cálculo do valor médio da distância entre os marcadores. Obteve-se, após a mensuração em 100 quadros, o valor médio de 43,7cm com coeficiente de variação de 0,8 por cento. Estes resultados mostram que a metodologia desenvolvida é precisa e adequada para o estudo da locomoção de eqüinos

A methodology used for the study of human movement was adapted to analyze the movement of equines in a high performance treadmill. An electronic high precision theodolite was used to construct a calibration system to demarcate the volume occupied by the animal. It was taken the three dimensions coordinates of each marker present in the calibrator, composing the calibration archive. Two video cameras (60 Hz) were located approximately 5m from the left lateral side of the treadmill at 1.8m height. The images had been fit using a video monitor. For the validation of the method, a member of the team moved into the calibrated space, a 43.8cm long rigid stick with markers settled in its extremities. For the analysis of the images, the Dvideow program developed by the Laboratório de Instrumentação para Biomecânica - UNICAMP was used. After the three-dimensional reconstruction of the images, the calculation of the distance between the markers of the stick was done in 100 frames. The mean was 43.7 cm with a variation coefficient of 0.8 percent. These results confirm that this methodology is precise and adequate for the study of the locomotion in horses

Three-dimensional analysis of the normal dentition and edentulous maxilla of Koreans / 대한치과보철학회지

STAEMENT OF PROBLEM: In Korea, the preliminary impression trays for dental and edentulous maxillae are manufactured on the base of the statistical value of Westerners. There had been less study on the dental and edentulous arches of Koreans. PURPOSE: The purpose of this study was to evaluate an average dental cast, preliminary impression trays, three-dimensional relation of dental and edentulous maxilla of Koreans. MATERIAL AND METHODS: The subjects for this study were 173 dental casts of maxilla (dental: 52, edentulous: 146) with ages 18~60 years old. Each of the master casts was measured 69 measuring points on the dental cast of maxilla, and 46 measuring points on the edentulous cast of maxilla with three-dimensional digital measuring machine. Each measuring points were analysed and were overlapped, that three dimensional dental graphic manufactured by CAD/CAM system. RESULTS: 1. A standard of distribution to alveolar bone were width between left and right buccal border lines of the standard 3/4 line. The mean value of dental and edentulous casts were 67.27mm, 63.49mm, respectively. 2. Morphological classification of dental casts were divided into three groups of V-shape, O-shape, U-shape, that proportion of distribution were 17%, 16%, 67%, respectively. Dimensional classification of the dental casts were divided into five groups of less than 63mm, 63 up to 65mm, 65 up to 67mm, 67 up to 69mm, more than 69mm, respectively. 3. Morphological classification of edentulous casts were divided into three groups of V-shape, O-shape, U-shape, that proportion of distribution were 18%, 17%, 65%, respectively. Dimensional classification of the edentulous casts were divided into five groups of less than 57mm, 57 up to 61mm, 61 up to 65mm, 65 up to 69mm, more than 69mm, respectively. 4. Mean dental and edentulous cast of maxilla were overlapped, the proportion of bone resorption to alveolar bone is higher than that of palatal bone, its difference were higher anterior 2/4 area than posterior 3/4 area. CONCLUSION: It obtains information of preliminary impression trays for dental and edentulous maxilla of Koreans.

Three Dimensional Analysis of Normal Smiles in Korean

Smile reconstruction through restorating the movement of the upper and lower lips and the nasolabial fold for facial paralysis, is the one of the most important fields of plastic and reconstructive surgery. It is necessary to understand and analyze the normal smile in planning the surgery for facial paralysis. Fifty volunteers(25 men and 25 women) have been measured using 6-mm digital video camera with various computer programs to get the most spontaneous smile. Stop frames from the cycle of smile were captured in frontal, both lateral, and inferior views and the differences between resting and maximum smiling states were compared. Each subject had ten points marked on the lips and nasolabial creases. The distance and angle between each point of two states were measured and converted into x, y and z components in three dimensional space. Averages of each component were calculated. Average movement, average angle on coronal plane, and average posterior angle were 13.7 mm, 52.2 degrees, and 48.9 degrees at commissure, 10.5 mm, 56.3 degrees, and 31.4 degrees at nasolabial fold, 7.3 mm, 88.1 degrees, and 33.3 degrees at center of upper lip, 10.1 mm, 57.2 degrees, and 30.9 degrees at mid-lateral upper lip, 5.9 mm, -87.5 degrees, and 66.9 degrees at the center of lower lip, and 6.7 mm, -12.7 degrees, and 61.5 degrees at mid-lateral lower lip respectively. This study was tried to define the basis of smile in reconstruction of facial paralysis and to suggest the objective method of assessing preoperative state and postoperative result. Further studies should be followed to establish the standardized useful data for smile reconstruction.