A 3-D finite element study of the influence of crown-implant ratio on stress distribution

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Stress distribution in bone simulation model with pre-angled implants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Does a mandibular RDP and new maxillary CD improve masticatory efficiency and quality of life in patients with a mandibular Kennedy class I arch?

To evaluate the change in masticatory efficiency and quality of life of patients treated with mandibular Kennedy class I removable partial dentures (RPDs) and maxillary complete dentures at the Department of Dentistry of the Federal University of Rio Grande do Norte. A total of 33 Kennedy class I patients were rehabilitated with maxillary complete dentures, and mandibular RPDs were selected for this non-randomized prospective intervention study. The patients had a mean age of 59.1 years. Masticatory efficiency was evaluated by colorimetric assay using fuchsin capsules. The measurements were conducted at baseline and 2 and 6 months after prosthesis insertion. Quality of life was evaluated using the Oral Health Impact Profile (OHIP-14) at baseline and 6 months after denture insertion. The Kolmogorov-Smirnov normality test was applied. Masticatory efficiency was evaluated by repeated measures ANOVA. Oral health-related quality of life was compared using the paired t test. There was no statistically significant difference in masticatory efficiency after denture insertion (p = 0.101). Significant differences were found (p = 0.010) for oral health-related quality of life. A significant improvement in psychological discomfort (p < 0.01) and psychological disability (p < 0.01) was observed. Mean difference value (95 % confidence interval) was 6.8 (3.8 to 9.7) points, reflecting a low impact of oral health on quality of life, considering the 0-56 range of variation of the OHIP-14 and a Cohen's d of 1.13. According to the results of the present study, rehabilitation with Kennedy class I RPDs and complete dentures did not influence masticatory efficiency but improved oral health-related quality of life. The association between the patient's quality of life and the masticatory efficiency is important for treatment predictability.

Analysis of the biomechanical behavior of short implants: the photo-elasticity method

The aim of this study was to analyze the stress distribution of short implants supporting single unit or splinted crowns by the photo-elasticity method. Four photo-elastic models were produced: A (3.75×7mm); B (3.75×7mm, 3.75×7mm and 3.75×7mm); C (3.75×10mm, 3.75×7mm and 3.75×7mm); D (3.75×13mm, 3.75×7mm and 3.75×7mm). The prostheses were made with Ni-Cr alloy. A load of 100N in the axial and oblique directions was applied, totaling 380 applications, individually capturing their images in each model. The data were randomized and analyzed qualitatively and quantitatively by 2 examiners. The oblique loading was significantly more damaging. The increase in length was favorable for stress distribution (p<0.05). The splinting was beneficial for the transmission of stresses mainly (p<0.05). The splinting of the crowns, as well as increasing the length of the first implant and axial loading was most beneficial in the stress distribution. Short splinted implants behaved better than single unit implants. Increasing of the length of the first implant significantly improved the stress distribution in all analyzed situations.

Estudo da resistência à tração de cápsulas e troqueis metálicos cimentados, em função de alívio e retenção para o cimento

Pós-graduação em Odontologia Restauradora - ICT

Efeito da infiltração de sílica pelo método sol-gel na resistência à flexão de bicamadas de porcelana e Y-TZP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Impacto do uso de fita adesiva na qualidade de vida de pacientes institucionalizados e usuários de próteses totais convencionais

Objective: Evaluate the impact of the use of strip adhesive over the quality of life of institutionalized patients and wearers of complete dentures. Material and method: Twenty-nine institutionalized patients wearers of complete denture were selected to this study and after a clinical exam, a questionnaire (adjusted and based upon the index of Oral Health Impact Profile and Oral Health-Related Quality of Life, OHIP and OHQOL) was applied to evaluate issues related to epidemiological conditions (gender and age), quality of life (pain, discomfort, functional limitations, phonetic, social, psychological and esthetic), taste and notion of implant treatment. Following this part, the patients received instruction to use the strips adhesives (Corega Fita Adesiva, Glaxo-Smith-Kline, Rio de Janeiro, Brazil), considering three in maxillary prosthesis and two in the lower prosthesis during a period of 30 days. After this period, all the patients were recall and the questionnaire was reapplied; add some adhesive performance questions, to compare the results before and after the adhesive use in terms of percentage. Result: After the adhesive strips use there were improvement of the functional, social and physcological limitation aspects, but without percentual increasement of phonetic and esthetics aspects. The results showed 65.5% of the answers stating adhesive maintenance between 6-12 hours, easy removal (68.9%), and without change the taste (89.6%). The notion for implant treatment was decreased changing from 75.8 to 37.9% after the adhesive use. Conclusion: The results enhanced a positive impact over quality of life of the respondents after the strip adhesive use, showing decrease of pain and discomfort, mainly of inferior dental prosthesis.

Planejamento reverso em implantodontia: relato de caso clínico

The oral rehabilitation has achieved great prominence in the dental implant, especially in the cases of reposition of units dental elements, so it is possible to replace each missing element to implant into your space where the tooth was loss. The reverse planning is fundamental to an appropriate rehabilitation, because promote the elimination of problems that might compromise the aesthetics and function of future dental implants. The objective of this study was to report the treatment plan for a patient in need of oral rehabilitation with implant dental prosthesis, using indications and techniques based on the literature, emphasizing the importance of reverse planning. We conducted an osseointegrated implant surgery using the principles of a connect procedure, thus allowing their successfully installing increasing the predictability of treatment. It is concluded that the success of rehabilitation treatment is directly related to the initial planning, a correct clinical approach and an integrated multidisciplinary team.

Halitose na geriatria: diagnóstico, causas e prevalência

Halitosis is the unpleasant odor of exhaust air through the mouth and lungs. There are over 50 causes, and approximately 90% of cases, is of oral origin. May have physiological origin (stress, breath of morning, fasting, and inappropriate diets), local reasons (bad oral hygiene, bacterial plaque retained on the tongue and/or tonsils, lower production of saliva, gum disease) or systemic reasons (diabetes, kidney or liver problems, constipation, etc.). In the Third Age, this problem tends to increase significantly. Thus, the aim of this study was to detect the presence of halitosis in the geriatric group attended in the dental clinic of UNIRP, identifying their incidence and principal causes. The sample consisted of 48 volunteer patients aged 60 years or older and included more than 90% of patients treated in this age group. It was performed a anamnesis and physical examination. The intra-oral halitosis was detected using a breath meter (halimeter). In the group studied, approximately 54.16% had halitosis, 84.61% of these were users of the prosthesis. The tongue coating was present in 80.76% of individuals with halitosis. After brushing the tongue, 88.46% of patients with halitosis have had the initial index oral malodor decreased. Based on the results of this study it was concluded that factors as dental prostheses and tongue coating are critical factors in causing halitosis.

Influence of morphological variables in photoelastic models with implants submitted to axial loading

Purpose: This study used 12 photoelastics models with different height and thickness to evaluate if the axial loading of 100N on implants changes the morphology of the photoelastic reflection. Methods: For the photoelastic analysis, the models were placed in a reflection polariscope for observation of the isochromatic fringes patterns. The formation of these fringes resulted from an axial load of 100N applied to the midpoint of the healing abutment attached to the implant with 10.0mm x 3.75mm (Conexão, Sistemas de Próteses, Brazil). The tension in each photoelastic model was monitored, photographed and observed using the software Phothoshop 7.0. For qualitative analysis, the area under the implant apex was measured including the green band of the second order fringe of each model using the software Image Tool. After comparison of the areas, the performance generated by each specimen was defined regarding the axial loading. Results: There were alterations in area with different height and thickness of the photoelastic models. It was observed that the group III (30mm in height) presented the smallest area. Conclusion: There was variation in the size of the areas analyzed for different height and thickness of the models and the morphology of the replica may directly influence the result in researches with photoelastic models.

Nível de satisfação dos pacientes edêntulos reabilitados com prótese total na faculdade de odontologia de Adamantina FAI

The population’s life expectancy is growing every year. This fact highlights the importance of the elderly for the dentistry. The oral cavity quality has great influence on quality of life at both the biological and the psychological and social factors by maintaining a self-esteem, self-expression, communication and satisfactory facial aesthetics. Unfortunately, the number of edentulous elderly population is also high, which may create problems to their social life. Therefore, the objective of this study was to demonstrate and evaluate the difficulties of treating edentulous patients, comparing data prior to treatment to post data after treatment by complete dentures made to the patients undergoing oral rehabilitation in the Dental Clinic of the Faculty of Dentistry of Adamantina – FAI. For this study, questionnaires were filled in the form of answers developed alternative focused on the degree of patient satisfaction, the current situation of occlusion, and outcome of treatment. The results showed that 96% of patients were satisfied with the results obtained in the treatment, all of whom believed that the prosthesis helped them feel better aesthetically and improved self-esteem. By this methodology, it was concluded that the degree of satisfaction was high, but the services provided must be constantly reevaluated, once the elderly population presents a wide labor market for dental professionals and demand level services will certainly increase each year.

Influência do aumento do comprimento de implantes dentários

The use of implants of greater length may be more favorable for the predictability of dental implants. This statement is relevant, since the cause of failures in dental implants are more related to biomechanical complications. The aim of this study was to evaluate the influence of increase of the length around the entire body of the implant. Six models were created with the presence of only one hexagonal implant (Master Screw connection, Implant Systems, São Paulo, Brazil) of 3.75 mm x 7.0 mm (Model A), 3.75 mm x 8.5 mm (Model B ), 3.75 mm x 10.0 mm (Model C) 3.75 mm x 11.5 mm (Model D) 3.75 mm x 13.0 mm (Model E) 3.75 mm x 15.0 mm (Model F) using the method of photoelasticity. The results were visualized through a qualitative analysis of stresses (number and intensity photoelastic fringes). The model A showed a pattern of less favorable stress distribution, the oblique loading was the most detrimental to the related structures. Conclusion: The increased length allowed for a better distribution of stresses. The oblique loading was more detrimental when compared to axial loading.

Análise Biomecânica em implantes com diferentes tipos de conexão: estudo pelo MEF-3D

The aim of this study was to evaluate the biomechanical behavior of different implant connection types, by means of three-dimensional finite element analysis. 3 Three-dimensional models were created with a graphic modeling software: SolidWorks 2006 and Rhinoceros 4.0, and InVesalius (CTI, São Paulo, Brasil), the bone was obtained by computerized tomography of a sagittal section of the molar region. The model was composed by bone block with an implant (4 x 10 mm) (Conexão Sistemas de Prótese, São Paulo), with different implant connections: external hex, internal hex and Morse-taper with the corresponding prosthetic component Ucla or Morse-taper abutment. The Three-dimensional models were transferred to finite element software Femap 10.0 (Siemens PLM Software Inc., CA, USA), to generate a mesh, boundary conditions and loading. An axial (200N) and oblique load (100N) was applied on the occlusal surface of the crowns. Analyses were performed using the finite element software NEiNastran 9.0 (Noran Engineering, Inc., USA) and transferred to the Femap 10.0 to obtain the results; after the results were visualized using von Mises stress maps and Maximum stress principal. The results showed the stress distribution was similar between models, with a little superiority of Morse-taper connection. It was concluded that: the three connection types were biomechanical viable; The Morse-taper connection presented the better internal stress distribution; there was not significant biomechanical differences on the bone.

Implantes Platform Switching: longevidade e preservação óssea: revisão crítica da literatura

The concept of switching platform is the use of an implant by platform wider than the abutment. Recently, researches have shown that this type of dental implant design tends to offer a higher preservation of crestal bone when compared to the traditional pattern of bone loss. The present study aims to perform a critical review on the switching platform concept establishing possible advantages of the technique. A search was performed on Medline/Pubmed about the topic “dental implant” and “platform switching”, and after applying inclusion criteria 40 studies were selected. The literature on longevity present prospective studies that show less bone loss, studies in biomechanics exhibit better or similar stress distribution around the bone crest, however, is not yet defined the role of the biological width. Thus, studies of longevity, and randomized prospective studies are of a great relevance to be performed in order to confirm the benefits of this technique and to establish a protocol indication. It is possible, based on this literature review, to conclude that longitudinal and randomized studies show that the platform switching implants have longevity and less bone loss. Biomechanically, the technique is possible.

Plástica gengival associada à laminados cerâmicos para resolução estética

Sometimes we face clinical situations in which the lack of harmony in the smile is caused by a major exhibition of the gingival tissue. In these cases the professional should be able to perform a detailed analysis of the static and dynamic components of the smile, in search of a satisfactory planning and treatment which may include different dental specialties. For these situations, the association of periodontics/prosthesis is a viable alternative that has been used positively in search of an aesthetic and functional condition that benefits the patient, without leaving aside the preservation of periodontal tissues and of the remaining structure of the tooth. Thus, the aim of this study was to describe a case in which the association between these two areas was proposed to correct gummy smile and dental vestibularization. Clinical results and the satisfaction of the patient indicate that this multidisciplinary treatment combining periodontal and prosthetic techniques is favorable to positive results in cases of compromised smile aesthetics due to excessive gum tissue.