Prediction, analysis and application of learning curve of tooth preparation for all ceramic crowns of maxillary central incisors / 北京大学学报(医学版)

OBJECTIVE@#To predict the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training based on the modified Wright learning curve model, then to analyze and applicate the learning curve.@*METHODS@#Twelve graduate students participating in standardized dental resident training were selected to prepare the resin maxillary central incisors on phantom head simulators for all ceramic crowns 4 times. The results of preparation were evaluated by 3 prosthetic experts with at least 10 years' experience focusing on the reduction, contour, taper, shoulder, finish line, margin placement, adjacent tooth injury, and preparation time for tooth preparation. The learning rate of tooth preparation was calculated by scores of tooth preparation of 4 times. The learning curve of tooth preparation was predicted based on the modified Wright learning curve model. According to the criteria of standardized training skill examinations for dental residents in Beijing, 80 was taken as the qualified standard score. The minimum training times for tooth preparation to satisfy the qualified standard score (80) was calculated, to analyze the characteristics of learning curve and evaluate the effectiveness of tooth preparation.@*RESULTS@#The scores of 4 tooth preparation were 64.03±7.80, 71.40±6.13, 74.33±5.96, and 75.98±4.52, respectively. The learning rate was (106±4)%, which showed the learning curve an upward trend. There were no significant differences between the qualified standard score and the predicted scores of tooth preparation from the 5th preparation to the 13th preparation (P > 0.05). The predicted score of the 14th preparation was higher than the qualified standard score (P < 0.05).@*CONCLUSION@#The trend of the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training is upward, which predicts the minimum training times higher than the qualified standard score is 14 times.

Influência da técnica de preparo sobre o contorno cervical dos laminados cerâmicos: relato de caso / Influence of the preparation technique on the cervical contour of ceramic laminates: a case report / Influencia de la técnica de preparación en el contorno cervical de los laminados cerámicos: reporte del caso

Introdução: Devido à crescente demanda estética, a odontologia restauradora se renova na intenção de alcançar melhores resultados na harmonia do sorriso. Entretanto, a atenção deve voltar-se também aos tecidos periodontais, visto que há uma integração entre material restaurador e os tecidos. Objetivo:Descrever e discutir as etapas clínicas para a confecção de laminados cerâmicos, atentando-se a preparos minimamente invasivos, contorno cervical e fatores que podem intervir na longevidade do procedimento.Relato de caso:Paciente do sexo masculino, 28 anos de idade, compareceu a Associação Brasileira de Odontologia, seção de Alagoas, relatando insatisfação em relação ao tamanho dos seus dentes. Os arcos superior e inferior foram moldados para a obtenção dos modelos de estudo e enceramento diagnóstico. Ao início do tratamento foi orientado ao paciente clareamento dental pela técnica combinada. O preparo dos dentes foi guiado por uma matriz de silicone, sendo estes uniformes e conservadores, seguido de moldagem, fase laboratorial e cimentação final. Finalizado o caso foi realizado o ajuste oclusal solicitando ao paciente que realizasse movimentos de lateralidade e protrusão. Conclusões:A técnica do preparo influência na longevidade dos laminados cerâmicos, por relacioanar-se à adesão e a saúde periodontal. O preparo deve ser mínino e limitado ao esmalte dental sempre que possível, determinando assim um maior e melhor prognóstico (AU).

Introduction:Due to the growing aesthetic demand, restorative dentistry is renewed to achieve better results in smile harmony. However, attention should also be turned to periodontal tissues since there is an integration between restorative material and tissues. Objective:To describe and discuss the clinical steps for the manufacture of laminate veneers, paying attention to minimally invasive preparations, cervical contour, and factors that can intervene in the procedure's longevity. Case report:A 28-year-old male patient attended the Brazilian Dental Association, the Alagoas section, reporting dissatisfaction with his teeth' size. The upper and lower arches were molded to obtain the study and diagnostic waxing models. At the beginning of treatment, the patient was instructed by the combined technique. After the case, the occlusal adjustment was performed, asking the patient to perform laterality and protrusion movements. Conclusions:The preparation technique influences the longevity of laminate veneers due to adherence and periodontal health. The preparation should be minimal and limited to dental enamel whenever possible, thus determining a higher and better prognosis (AU).

Introducción: Debido a la creciente demanda estética, la odontología restauradora se renueva para lograr mejores resultados en la armonía de la sonrisa. Sin embargo, también se debe prestar atención a los tejidos periodontales ya que existe una integraciónentre el material restaurador y los tejidos.Objetivo: Describir y discutir los pasos clínicos para la confección de carillas laminares, prestando atención a las preparaciones mínimamente invasivas, al contorno cervical y a los factores que pueden intervenir en la longevidad del procedimiento.Reporte del caso: Un paciente masculino de 28 años asistió a la Asociación Dental Brasileña, sección de Alagoas, reportando insatisfacción con el tamaño de sus dientes. Los arcos superior e inferior fueron moldeados para obtener los modelos de depilación de estudio y diagnóstico. Al comienzo del tratamiento, el paciente fue instruido por la técnica combinada. La preparación de los dientes fue guiada por una matriz de silicona, siendo estas uniformes y conservadoras, seguidas de moldeo, fase de laboratorio y cementación final. Después del caso, se realizó el ajuste oclusal, pidiendo al paciente que realizara movimientos de lateralidad y protuberancia. Conclusiones: La técnica de preparación influye en la longevidad de los laminados cerámicos, debido a la adherencia y la salud periodontal. La preparación debe ser mínima y limitada al esmalte dental siempre que sea posible, determinando así un pronóstico más alto y mejor (AU).

Clinical pathway and preparation method of high-precision tooth shoulder platform / 华西口腔医学杂志

A clear shoulder platform that can be easily identified by doctors and technicians or machines (mouth scan and warehouse scan) is important to obtaining a good long-term and stable fixed prosthesis treatment effect. At present, the pre-paration of the shoulder platform is usually based on free hands, and the practical operation is mainly guided by experience. Moreover, no comprehensive and objective preoperative design, intraoperative verification, and final test are available. Thus, the accuracy of shoulder platform preparation needs to be improved. In this study, the clinical pathway of "three determination, three selection, and three steps" with high accuracy of preparation and the precise shoulder preparation method of "bur-tip guidance" are proposed in detail.

Reabilitação com coroas metal free em dentes anteriores traumatizados e com rizogênese incompleta: relato de caso / Rehabilitation with metal free crowns in traumatized anterior teeth with incomplete rhizogenesis: case report

Objetivo: rizogênese incompleta refere-se a dentes permanentes em que não houve a formação completa do ápice radicular, ocasionando perda da vitalidade pulpar e, consequentemente, incapacidade da bainha epitelial de Hertwig para induzir a formação completa da raiz. Devido ao traumatismo e escurecimento dental, se faz necessário em certos casos a confecção de coroas em porcelana pura para reabilitar a paciente em estética e função. O presente trabalho tem como objetivo demonstrar um caso de reabilitação estética e funcional em dente com rizogênese incompleta, onde se consideraram as perdas estruturais e alteração de cor, para que seja possível estabelecer o tratamento mais adequado. Relato de caso: paciente de 16 anos, gênero feminino, atendida na Clínica de Odontologia de uma instituição privada, insatisfeita com a estética do seu dente devido ao escurecimento do elemento 21, pois quando tinha 5 anos o dente foi traumatizado juntamente com o elemento 11. O plano de tratamento adotado para ambos os elementos foi a confecção de peças protéticas em porcelana e cimentação. Considerações finais: esse caso demonstrou que a confecção de coroas estéticas em porcelana é considerada uma boa conduta na rotina clínica em casos de escurecimento dental, devolvendo estética e função para o paciente.(AU)

Objective: incomplete rhizogenesis refers to permanent teeth with incomplete formation of the root apex, causing loss of pulp vitality and the consequent inability of the Hertwig epithelial sheath to induce complete root formation. Due to dental trauma and darkening, some cases require the production of pure porcelain crowns to rehabilitate the aesthetics and function of patients. The present study aims to show a case of aesthetic and functional rehabilitation in a tooth with incomplete rhizogenesis, in which structural losses and color change were considered to establish the most appropriate treatment. Case report: a 16-year-old female patient treated at the Dental Clinic of a private institution. The patient was not satisfied with the aesthetics of her tooth due to the darkening of element 21, because at 5 years old the tooth was traumatized along with element 11. The treatment used for both elements was the production of prosthetic porcelain crowns and cementation. Final considerations: this case showed that the production of aesthetic porcelain crowns is considered a good conduct in the clinical routine in cases of tooth darkening, returning aesthetics and function to the patient.(AU)

Consideraciones periodontales y protéticas para el tallado de piezas dentarias / Periodontal and prosthetic considerations for teeth grinding

Las preparaciones dentales para prótesis fija, involucran al tejido duro, además la proximidad que existe con la encía hace necesario la comprensión de su estructura y la función del aparato de protección, para que las restauracionesno invadan el ancho biológico constituido por el epitelio de unión y las fibras gingivales; basándonos en los estudios de Gargiulo en 1961, donde la inserción del tejido conjuntivo mide 1.07 mm y la adherencia epitelial 0.97 mm en promedio, sumados al espacio del surco gingival. El biotipo periodontal es de vital importancia para la elección de la altura de terminación del hombro de la preparación, donde el mismo deberá establecerse, previo sondaje óseo a no menos de 2.5 mm de la cresta según Kois (2008). La utilización de materiales y técnicas para la toma de impresiones definitivas deben ser amigables con los tejidos blandos a fin de no producir alteraciones y que las restauraciones sean predecibles, tanto funcional como estéticamente en el transcurso del tiempo

Dental preparations fixed prosthesis, involving the hard tissue, there is also proximity to the gum is necessary to understand the structure and function of the protection device, to restorations without invading the biologic width consisting of the epithelium junction and the gingival fibers; based on Gargiulo studies in 1961, where the insertion of the connective tissue and epithelial measured 1.07 mm 0.97 mm in average adhesion, coupled with sulcular space. The periodontal biotype is of vital importance for the choice of the termination of the shoulder height of the preparation, where it must be established prior tobone sounding no less than 2.5mm crest according Kois (2008). The use of materials and techniques for making final impressions should be friendly soft so as not to alter tissues and restorations predictable, both functionally and aesthetically over time.

Reconstitution coronoradicualire preprothetique sur dent anterieure: Inlay core ou reconstitution foulee avec un temoin en fibre de verre

L'objectif de ce travail qui rentre dans le cadre d'un essai clinique randomise; est de comparer l'efficacite des inlay cores a celle des reconstitutions foulees avec des tenons en fibre de verre sur les dents anterieures quelque soit leur statut prothetique. Nous avons selectionne un total de 182 dents anterieures; sur 131 patients pris en charge. 83 dents ont recu des inlay cores ; et 99 dents ont recu des reconstitutions foulees avec des tenons en fibre de verre. Pour une duree de suivi moyenne de 30 mois; nous avons denombre 6 echecs (7;2% IC=[2;70-15;07]); survenus sur les 83 inlay cores soit 2 cas de reinfection endodontique; 2 cas de fracture radiculaire oblique cervicale; un descellement au cours de la taille du faux moignon; et un cas de descellement de l'inlay core avec la couronne definitive. 24 echecs (24;74% IC=[16;19 -33;89]) sont survenus sur les 97 reconstitutions avec tenons en fibre de verre en prenant en consideration les deux reconstitutions perdues de vue; soit 22 cas de descellements; et 2 cas de reinfection endodontique. L'analyse des resultats de l'etude; retrouve une difference significative en faveur des inlay cores avec un taux de succes de 98;73% ( IC= [93;15-99;97]) versus 87;5% (IC= [78;7393;59]) pour les reconstitutions avec des tenons en fibre de verre quelque soit leur statut prothetique; avec un p=0;0045 au risque ?=5% et une puissance de 80% du test statistique. L'inlay core trouve son indication dans tous les cas; et surtout face a un delabrement important interessant les quatre parois ne laissant que 2 mm de hauteur des tissus durs en supra gingival ; et ceci quelque soit le statut prothetique qu'assumera la dent anterieure ainsi reconstituee. Le succes des reconstitutions foulees avec des tenons en fibre de verre est conditionne par le nombre de parois delabrees; et par la hauteur des tissus residuels. Un delabrement de plus de 3 parois laissant une hauteur de tissus durs de moins de 3 mm constitue une contre indication a leur utilisation. Le caractere unitaire de la restauration prothetique sur une dent anterieure semble diminuer le taux de l'efficacite de la reconstitution corono radiculaire. Il s'avere que les reconstitutions foulees avec des tenons en fibre de verre resistent moins aux contraintes non axiales generees par un element prothetique qui supporte un crochet d'une prothese partielle amovible par rapport aux inlay cores (p=0;028)

Effects of different tooth preparations on three-dimensional adaption of crowns based on the reverse engineering / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of different tooth preparations on three-dimensional adaption of computer aided design and computer aided manufacturing (CAD/CAM) crowns based on the reverse engineering.</p><p><b>METHODS</b>The tooth preparation model of the left maxillary first molar was scanned to build five different tooth preparations using the NX Imageware 13.2 software. The resin cores (n=8) were designed with the exocad software. The scanning data of the inner surface of each resin core were used to analyze the three-dimensional adaption with the Geomagic Qualify 12 software.</p><p><b>RESULTS</b>According to the color-coded deviation images, the deviation of the heavy chamfer shoulder was the smallest and the most uniform, whereas the other groups with sharp lines showed large deviation. After statistical analysis, the total deviation of the heavy chamfer shoulder, 135° shoulder, feather shoulder, 90° shoulder with lipped margins, and sharp marginal ridges preparation were (16.88±2.83), (26.88±3.61), (53.56±4.30), (51.38±4.46), and (47.19±4.62) μm. A statistical significance was observed between the heavy chamfer and 135° shoulders (P<0.05). The other groups fitted poorly, without statistical significance between each group (P>0.05).</p><p><b>CONCLUSION</b>Three-dimensional analysis using a computer is a preferable method to study the three-dimensional adaption of crowns. The heavy chamfer shoulder and round line preparation are clinically recommended. However, feather shoulder, 90° shoulder with lipped margins, and sharp marginal ridge preparation should be avoided.</p>

The reliability of an easy measuring method for abutment convergence angle with a computer-aided design (CAD) system

PURPOSE: The purpose of this study was to evaluate the intra-rater reliability and inter-rater reliability of three different methods using a drawing protractor, a digital protractor after tracing, and a CAD system. MATERIALS AND METHODS: Twenty-four artificial abutments that had been prepared by dental students were used in this study. Three dental students measured the convergence angles by each method three times. Bland-Altman plots were applied to examine the overall reliability by comparing the traditional tracing method with a new method using the CAD system. Intraclass Correlation Coefficients (ICC) evaluated intra-rater reliability and inter-rater reliability. RESULTS: All three methods exhibited high intra-rater and inter-rater reliability (ICC>0.80, P<.05). Measurements with the CAD system showed the highest intra-rater reliability. In addition, it showed improved inter-rater reliability compared with the traditional tracing methods. CONCLUSION: Based on the results of this study, the CAD system may be an easy and reliable tool for measuring the abutment convergence angle.

Laminados cerâmicos: técnica não invasiva / Laminate veneer: non-invasive technique

Atualmente, o cuidado com a estética vem sendo valorizado de tal forma que, além de ser um referencial de saúde, ter um sorriso bonito significa também estar em harmonia consigo mesmo e ser uma pessoa bem sucedida. Dentro da Odontologia, a procura por um sorriso harmonioso e bonito vem crescendo a cada dia. Essa busca está diretamente relacionada a fatores sociais, culturais e psicológicos, que se alteram em função do tempo, dos valores de vida e da idade do indivíduo. Uma alternativa para a correção de imperfeições nos dentes é a utilização dos laminados cerâmicos que restabelecem a forma, cor, função e harmonia do sorriso, além de proporcionar longevidade do tratamento e satisfação plena do cliente. Os laminados cerâmicos são indicados para a correção de imperfeições dentárias, fraturas e dentições desgastadas pelas forças mastigatórias, substituindo estruturas defeituosas por um esmalte artificial integrado funcional e biologicamente aos tecidos dentários e periodontais. O estudo da resistência à fratura e à fadiga dos laminados cerâmicos fornece dados relativos ao reforço, estabilidade e a manutenção da estrutura dentária, prevenindo o preparo total da coroa dental. O presente relato apresenta, com base na literatura, uma reabilitação estética do sorriso usando laminados cerâmicos sem realização de preparo ou desgaste dos dentes. A comunicação harmônica entre o cirurgião dentista, TPD e os critérios científicos de planejamento são de fundamental importância para a obtenção resultados estéticos e funcionais com longevidade clínica.

Nowadays, the care with aesthetics aspects has been valued in such a way that, besides being an indicator of health, a beautiful smile is also associated to be in harmony with yourself and being a successful person. In Dentistry, the search for a beautiful and harmonious smile is increasing each day. This search is directly related to social, psychological and cultural factors that change with time, as with life values and age of the person. An alternative to correct dental imperfections is the use of laminate veneers that restore the shape, color, function and harmony of the smile, as well as provide longevity to the treatment and the complete satisfaction of the patient. The laminate veneers are indicated for the correction of dental imperfections, fractures and teeth worn by chewing forces, replacing defective structures by artificial enamel functionally and biologically integrated to the dental and periodontal tissues. The study on fracture and fatigue resistance of the laminate veneer provides data on the reinforcement, stability and maintenance of the dental structure, preventing the total preparation of the dental crown. This report is based on the literature and presents an aesthetical rehabilitation of the smile using laminate veneers without the realization of preparation or wear of the teeth. An effective communication between dentist surgeon, dental technician and the scientific criteria of planning are fundamental for obtaining aesthetic and functional results with clinical longevity.

Comparison of patient's satisfaction level with complete dentures fabricated by neutral zone technique and conventional technique

The objective of the study was to compare the satisfaction level of edentulous patients provided with complete dentures that were fabricated by either the neutral zone technique or the conventional technique. For this a quasi experimental comparative study [Phase 2 trial] was carried out at Department of Prosthodontics, Armed Forces Institute of Dentistry, Rawalpindi, Pakistan from September 2006 to February 2008. Sixty edentulous patients were included in the study and randomly placed into two groups. Complete dentures were fabricated for these patients; by the neutral zone technique for Group A and by the conventional technique for Group B. The satisfaction level of patients was assessed after six months of denture insertion with the help of a questionnaire. In Group A, 8 were highly satisfied, 19 fairly satisfied and 3 poorly satisfied while in Group B, 3 were highly satisfied, 16 fairly satisfied and 11 poorly satisfied. Chi-square test revealed a significance of 0.03 [P < 0.05] regarding comparison of patient's satisfaction level in both the study groups. It was concluded that dentures fabricated by neutral zone technique were more stable and functionally better than conventional dentures

Masticatory efficiency between balanced and lingualized occlusion in complete denture wearers

The objective of the study was to compare the masticatory efficiency with balanced occlusion and lingualized occlusion in complete denture wearers. The study was conducted in the Department of Prosthodontics, Lahore Medical and Dental College, Lahore. Sixty edentulous patients were included in this study; patients were randomly divided into two groups by using Statistical Package for Social Sciences [SPSS version 10] software. Group A was provided with dentures fabricated with bilateral balanced occlusion and Group B with lingualized occlusion. The patient's masticatory efficiency was assessed after 2 months of denture insertion using the sieving method. Masticatory efficiency was statistically better in patients provided with complete dentures fabricated with lingualized occlusion than dentures with bilateral balanced occlusion. It was concluded patients provided with dentures fabricated with lingualized occlusal scheme were more comfortable with their dentures and were able to chew properly with ease and comfort

Prevalência dos tipos de arcos desdentados, preparo de boca e qualidade dos modelos para próteses removíveis na Paraíba / Prevalence of edentulous dental arch types, mouth preparation and quality of plaster models for removable partial dentures in the State of Paraiba

A prótese parcial removível instalada sem o preparo prévio da boca tende a se deteriorar precocente além de provocar danos ao aparelho mastigatório. Objetivo: Avaliar a execução do preparo da boca em modelos de trabalhos enviados para laboratórios de próteses dentárias, em cinco cidades do Estado da Paraíba. Material e métodos: Dois examinadores calibrados analisaram 1000 modelos de trabalho e preencheram para cada modelo um formulário com seis itens. Resultados: Revelaram que a arcada superior representou 53,1% da amostra. Com relação à classificação de Kennedy, 33,7% dos modelos pertenciam à classe III, 29,7% à classe I, 28,7% e 7,9% às classes II e IV respectivamente. Noventa e dois por cento da amostra não apresentou qualquer esboço de preparo da boca. Quanto ao material empregado para a obtenção dos modelos, 61% foram confeccionados com gesso tipo IV, 35,6% gesso tipo III e 3,4% gesso tipo II. Conclusões: Concluiu-se que o preparo da boca é realizado com menor frequência nas cidades do interior, mesmo assim o índice de preparo em João Pessoa é muito baixo

Removable partial dentures installed without prior mouth preparation tend to deteriorate prematurely, in addition to causing damage to the masticatory apparatus. Objective: To assess mouth preparation performance on master casts sent to prosthodontics laboratories in five towns located in the state of Paraiba. Materials and method: Two calibrated examiners analyzed 1,000 casts, filling out a six-item form for each cast. Results: Data revealed that the upper teeth represented 53.1% of the sample. As regards Kennedy's classification, 33.7% of the casts were Class III; 29.7% were Class I; 28.7% and 7.9% were Class II and Class IV, respectively. Ninety-two percent of the sample showed no trace of mouth preparation. In relation to the material used to obtain the casts, 61% were prepared using Type IV gypsum; 35.6% used Type III gypsum and 3.4% used Type II gypsum. Conclusion: Mouth preparation has been carried out less frequently in the inner towns, even though preparation rates in the state capital of Paraiba (Joao Pessoa) was found to be very low as well

Assessment of convergence angle of full-coverage porcelain fused to metal crowns in clinical practice.

Background: Full-coverage porcelain fused to metal crowns is commonly recommended for restoration of extensively damaged teeth. Ability of the dentist to adequately prepare teeth is fundamental to success and longevity of these restorations. Aims: This study was designed to compare recommended convergence angle and taper values of tooth preparation with clinically practiced values and to assess the factors such as tooth position, operator experience, vitality, and restorative status on convergence angle of prepared teeth. Setting and Design: It was a descriptive, cross-sectional study design and held at The Aga Khan University Hospital, Dental Section, for a period of 1 year. Materials and Methods: A minimum of 197 crown preparation models of molar and premolar teeth prepared by residents and specialists were collected in order to achieve the objectives of the study on the basis of convenient sampling technique. Statistical Analysis: One sample t-test used to compare the mean practiced convergence angle values with its recommended values. Independent sample t-test and one-way ANOVA was used to see difference in the convergence angle values of the teeth prepared by different operators, tooth type, vitality status, and restorative status of teeth. Results: Mean reported convergence angle and axial wall taper values were 23.7°±8.9° and 11.3°±7.8°, respectively, which is significantly greater (P<0.001) than the recommended values. Convergence angle values were greater for molars as compared to premolars. Conclusion: There was a considerable disparity between the convergent angles values recorded in this study and the recommended guidelines and are affected by tooth type, vitality, and restorative status of tooth.

Palateless custom bar supported overdenture: A treatment modality to treat patient with severe gag reflex.

Objective: To suggest a custom bar supported overdenture treatment modality for prosthodontic management of patients with severe gag reflex. Background: Some patients have a severe gag reflex and cannot tolerate conventional maxillary complete dentures with maximum palatal coverage and extensions of all borders. The condition further gets complicated in patients suffering from respiratory problems along with severe gag reflex. Severe gagging acts as a barrier to treat such patients with accepted clinical procedures and prevent patients from wearing the prosthesis. By saving some of the remaining natural teeth and fabricating, a horse shoe shape palateless simple tooth or bar supported overdenture can be successfully used for treating such patients. Materials and Methods: The remaining maxillary right and left canines were prepared with the tapered round end diamond bur to receive copings of custom bar after intentional root canal treatment of same teeth. Impression was made with light body and putty of the polyvinyl siloxane elastomer with double step putty wash technique. Impression was poured with die stone. Wax pattern of copings with bar was fabricated with inlay wax which was invested and casted. After retrieving the bar, it was finished and its fit was evaluated. The coping-bar assembly was finally cemented with the glass ionomer cement. Palateless overdenture was fabricated by conventional technique used for the fabrication of complete denture. Conclusion: Palateless custom bar supported overdenture procedure can be successfully used for the management of patients with severe gag reflex with improved denture retention, stability, chewing efficiency and comfort of the patient.

A CAD-CAM prosthodontic option and gingival zenith position for a rotated maxillary right central incisor: An evaluation.

Objective: Even with beautifully done restorations, an unattractive gingival zenith position, can negatively affect the smile of a person. In this short communication we describe the treatment of a rotated maxillary right central incisor using a digital photographic approach instead of the conventional approach. Background: The conjecture literature on prosthodontic considerations and gingival zenith position in cases of rotated maxillary central incisors is sparse. The gingival zenith level (GZL) in an apical-coronal direction of lateral incisors, relative to the gingival tangential zenith line joining the adjacent central incisor and canine, is approximately 1 mm under healthy conditions. Materials and Methods: For our patient, the treatment plan was decided by CAD-CAM technique as Zirconia, jacket crown. Clinical procedures included enameloplasty on the left central and right lateral maxillary incisors. Reduction of the rotated and crooked incisor was performed in the normal manner; periodontal plastic surgery was also done. Results: The patient expressed satisfaction with the intermediary (preliminary) two-dimensional photographs that were provided by the CAD-CAM system. The technique distinguished among the different treatment modalities for aesthetics and to relieve the emotional problems which were faced by female patient. The gingival zenith level of the rotated incisor was also improved. Conclusion: Digital imaging provides an immediate treatment option for the patients. Software also provides an interim aid, for the clinician as well as technician, in the form of two-dimensional photographs. CAD-CAM is entirely a helping instrument against the conservative prosthetic options and gingival zenith position for a rotated central incisor. It helps in patient education and in motivation.

The primary evaluation of minimal prepared ceramic veneer in anterior teeth for clinical application / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the clinical application value of minimal prepared ceramic veneer in anterior teeth, by analyzing the esthetic effects and success rates.</p><p><b>METHODS</b>Forty-four anterior teeth in 30 patients with minor esthetic defect were included in this study. Less than 0.5 mm preparation or no preparaion technique was used in the clinical procedure. Glass ceramics veneers were delivered and 3M Relyx Veneer were used as the adhesive. The final appearance of each restoration was evaluated by patients on visual analogue scales (VAS) and by professional prosthodontists. Evaluation criteria included margin effects, color, shape and translucency. The success rate of all the restoration were analyzed in 6, 12 and 24 month after the treatment.</p><p><b>RESULTS</b>The patients' degree of satisfaction was 9.2 ± 0.4, while the excellent rate of esthetic effect of margin effect, color, shape and translucency was 89% (39/44), 91% (40/44), 98% (43/44) and 93% (41/44) by professional prosthodontist. The success rate of 6, 12 and 24 month were 100% (44/44), 98% (43/44) and 91% (40/44).</p><p><b>CONCLUSIONS</b>The minimal prepared venneers have a good esthetic effect and a satisfactory success rate, and is a suitable technique in esthetic treatment under the critical indications.</p>

Análisis de la resistencia flexural a la fractura de restauraciones coronarias completas anteriores e porcelana pura (AU) / Analysis of the flexural fracture resistance of anterior all-ceramic crowns

Propósito: la influencia del tallado de diferentes diseños de la terminación marginal de la preparación dentaria y distintos espesores incisaless sobre la resistencia a la fractura de los sistemas de cerámica pura estudiados, es actualmente controvertida. Objetivo: el propósito de este estudio fue realizar una investigación in vitro para determinar la resistencia a la fractura de restauraciones coronarias completas de tres sistemas cerámicos estudiados, sobre preparaciones simuladas de incisivos centrales superiores. Materiales y métodos: se evaluaron tres sistemas de cerámica pura, con dos tallados diferentes de la terminación periférica de la preparación dentaria y dos espesores incisales cerámicos distintos. Se realizaron pilares metálicos como modelos de trabajo para evaluar la resistencia a la fractura, que fueron acondicionados para establecer condiciones reproducibles y una efectiva transferencia de fuerzas simulando una unión adhesiva completa entre la corona y las estructuras de los pilares que la soportan.

Prótesis fija estética conservadora y de costo razonable: investigación clínica prospectiva, 5 años / Conservative and esthetic fixed prosthodontics and at reasonable cost: 5-year follow-up

Las Prótesis Fijas de Resina Compuesta Reforzada con Fibra, han sido cuestionadas por limitaciones en cuanto a resistencia a la abrasión, hidrólisis y/o delaminación de la resina compuesta de recubrimiento. Sin embargo, perfectamente pueden ser alternativapara la reposición unitaria de premolares o molares. Son estéticas, conservadoras de los tejidos naturales, fáciles de elaborar tanto en la clínica como en el laboratorio, de costo razonable y no es insensato pensar que puedan perfectamente durar enservicio por unos 5 años.Como ventajas adicionales puede mencionarse que son factibles de reciclar y reparar en boca y que llegado el momento de recambio, son también muy fáciles de retirar sin afectar las estructuras naturales.Desde el año 2009, la Clínica de Prostodoncia Fija de la Universidad Católica del Uruguay está llevando adelante una investigación clínica prospectiva sobre este tipo de prótesis, que proveerá información sobre su comportamiento en boca por un períodode 5 años, con la presentación de un informe preliminar a los 3 años.

Fixed prosthesis made of fiber reinforced composites have been questioned by constraints in terms of resistance to abrasion, hydrolysis, and / or peeling of composite coating resins.However, perfectly they could be alternatives for the replacement of single posterior teeth lost. They are aesthetics and conservative of hard dental tissues. They also have reasonable cost, are simple to elaborate and it is realistic to think that they could last in service for about 5 years. They have additional advantages like the possibility to be easily recycled andrepaired in mouth and to be easily removed once their life expectancy had expired. Since 2009, the Clinic of Fixed Prosthodontics of the Catholic University is carrying out with a prospective clinical investigation of this kind of fixed prosthesis. The study will provide information about their behavior in the mouth for a period of 5 years, witha preliminary intermediate report to be presented at the third year.