Pedro Tortamano Neto

Use of Silver Nanoparticles Reduces Internal Contamination of External Hexagon Implants by Candida albicans

Since the dental implant/abutment interface cannot totally seal the passage of microorganisms, the interior of implant becomes a reservoir of pathogenic microorganisms that produce and maintain chronic inflammation in the tissues around implants. Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. The aim of this study was to evaluate the capacity of the nano-Ag to prevent the contamination of the implant internal surface by Candida albicans, caused by the implant/abutment microgap infiltration. Thirty-six implants were used in this experiment. Three study groups were performed: experimental group (implants receiving an application of nano-Ag in their inner cavity before installation of the abutment); positive-control group (implants receiving sterile phosphate buffer saline application instead of nano-Ag) and negative-control group (implants receiving the application of nano-Ag in the inner cavity and immersed in a sterile medium). In the positive-control and experimental groups, the implants were immersed in a Candida albicans suspension. The abutments of all three groups were screwed with a 10 N torque. After 72 h of immersion inC. albicans suspension or sterile medium, the abutments were removed and the inner surface of the implants was sampled with absorbent paper cone for fungal detection. No C. albicans contamination was observed in the negative-control group. The positive-control group showed statistically higher values of colony forming units (CFUs) of C. albicans compared with the experimental group. In conclusion, silver nanoparticles reduced C. albicans colonization inside the implants, even with low torque screw abutment.

Survival rate of titanium-zirconium narrow diameter dental implants versus commercially pure titanium narrow diameter dental implants: A systematic review

BACKGROUND Despite the existence of several studies validating the use of narrow diameter implants, most of them are based on pure Ti alloys. There is few clinical evidence of the success of TiZr narrow diameter implants (TiZr NDIs) regarding survival rate (SR) and marginal bone loss (MLB). PURPOSE The aim of this review was to systematically assess SR, as well as MBL of TiZr NDIs compared to commercially pure titanium narrow diameter implants (cpTi NDIs). MATERIAL AND METHODS The search was conducted in Medline/PubMed, Cochrane, Scopus, and Embase databases (year 2000 to November 2016). Cohort studies and randomized trials were included. RESULTS Six clinical studies from the 3453 articles initially identified met the inclusion criteria. There were no statistically significant differences in SR when TiZr NDIs and cpTi NDIs were compared in the 1-year follow up (P = .5), or when comparing TiZr NDIs placed in posterior and anterior regions. There was no difference between groups regarding 1-year SR: -0.01 (95% CI, -0.05-0.03) and MLB: -0.01 mm (95% CI: -0.14-0.12). CONCLUSION It can be concluded that TiZr NDIs present similar success rates and peri-implant bone resorption to cpTi NDIs.

Computer-aided analysis of digital dental impressions obtained from intraoral and extraoral scanners

Statement of problem The internal and marginal adaptation of a computer‐aided design and computer‐aided manufacturing (CAD‐CAM) prosthesis relies on the quality of the 3‐dimensional image. The quality of imaging systems requires evaluation. Purpose The purpose of this in vitro study was to evaluate and compare the trueness of intraoral and extraoral scanners in scanning prepared teeth. Material and methods Ten acrylic resin teeth to be used as a reference dataset were prepared according to standard guidelines and scanned with an industrial computed tomography system. Data were acquired with 4 scanner devices (n=10): the Trios intraoral scanner (TIS), the D250 extraoral scanner (DES), the Cerec Bluecam intraoral scanner (CBIS), and the Cerec InEosX5 extraoral scanner (CIES). For intraoral scanners, each tooth was digitized individually. Extraoral scanning was obtained from dental casts of each prepared tooth. The discrepancy between each scan and its respective reference model was obtained by deviation analysis (&mgr;m) and volume/area difference (&mgr;m). Statistical analysis was performed using linear models for repeated measurement factors test and 1‐way ANOVA (&agr;=.05). Results No significant differences in deviation values were found among scanners. For CBIS and CIES, the deviation was significantly higher (P<.05) for occlusal and cervical surfaces. With regard to volume differences, no statistically significant differences were found (TIS=340 ±230 &mgr;m; DES=380 ±360 &mgr;m; CBIS=780 ±770 &mgr;m; CIES=340 ±300 &mgr;m). Conclusions Intraoral and extraoral scanners showed similar trueness in scanning prepared teeth. Higher discrepancies are expected to occur in the cervical region and on the occlusal surface.

Accuracy of digital technologies for the scanning of facial, skeletal, and intraoral tissues: A systematic review

Statement of problem. The accuracy of the virtual images used in digital dentistry is essential to the success of oral rehabilitation. Purpose. The purpose of this systematic review was to estimate the mean accuracy of digital technologies used to scan facial, skeletal, and intraoral tissues. Material and methods. A search strategy was applied in 4 databases and in the non–peer‐reviewed literature from April through June 2017 and was updated in July 2017. Studies evaluating the dimensional accuracy of 3‐dimensional images acquired by the scanning of hard and soft tissues were included. Results. A total of 2093 studies were identified by the search strategy, of which 183 were initially screened for full‐text reading and 34 were considered eligible for this review. The scanning of facial tissues showed deviation values ranging between 140 and 1330 &mgr;m, whereas the 3D reconstruction of the jaw bone ranged between 106 and 760 &mgr;m. The scanning of a dentate arch by intraoral and laboratorial scanners varied from 17 &mgr;m to 378 &mgr;m. For edentulous arches, the scanners showed a trueness ranging between 44.1 and 591 &mgr;m and between 19.32 and 112 &mgr;m for dental implant digital scanning. Conclusions. The current digital technologies are reported to be accurate for specific applications. However, the scanning of edentulous arches still represents a challenge.

Accuracy of self-perforating impression tray for maxillary dental implant

| Objectives: To analyze the accuracy of a pre-fabricated self-perforating tray for implant impression in an edentulous maxilla. Methods: Four implants (13, 16, 23, 26) were placed in an acrylic resin model of an edentulous maxilla. Implant impressions (n = 7) were taken using a customized open tray (Control Group) and a pre-fabricated selfperforating tray (Test Group). A metal bar was fabricated and screw-retained on implant 13 and the vestibular gap between the framework and implants was measured by stereomicroscopy on implants 16, 23, and 26. Data were analyzed by ANOVA repeated measures and Tukey tests with a significance level (α) of 0.05. Results: There was no statistical difference between self-perforating and customized open tray groups. Control group showed a gap of 73.31± 26.01 for I1; 149.16± 53.90 for I2; and 115.46± 73.34 for I3. Whereas Test Group showed a gap of 154.41± 74.64 for I1; 159.45± 87.64 for I2; and 109.28± 49.18 for I3. Conclusion: The pre-fabricated self-perforating and custom trays showed a similar accuracy for implant impression of edentulous maxilla. DESCRIPTORS | Impression Technique; Dental Implants; Dimensional Measurement Accuracy. RESUMO | Precisão de moldeira autoperfurante para impressão de implante dentário maxilar • Objetivos: Analisar a precisão de uma moldeira autoperfurante de impressão pré-fabricada para implantes na maxila edêntula. Métodos: Quatro implantes (13, 16, 23, 26) foram colocados em um modelo de resina acrílica de uma maxila edêntula. As impressões dos implantes (n = 7) foram tiradas com uma moldeira aberta customizada (Grupo Controle) e uma moldeira autoperfurante pré-fabricada (Grupo Teste). Uma barra de metal foi fabricada e aparafusada no implante 13, e o gap vestibular entre a estrutura e os implantes foi medido por estereomicroscopia nos implantes 16, 23 e 26. Os dados foram analisados por Anova de medidas repetidas e teste de Tukey, com um nível de significância (α) de 0,05. Resultados: Não houve diferença estatística entre os grupos de moldeiras, tanto autoperfurante quanto aberta customizada. O grupo controle apresentou gaps de 73,31 ± 26,01 para I1; 149,16 ± 53,90 no I2; e 115,46 ± 73,34 para o I3. Ao passo que o Grupo Teste apresentou gaps de 154,41 ± 74,64 no I1; 159,45 ± 87,64 no I2; e 109,28 ± 49,18 para o I3. Conclusão: A moldeira autoperfurante pré-fabricada e a moldeira customizada apresentaram precisão similar na impressão de implantes da maxila edêntula. DESCRITORES | Técnica de Impressão; Implantes Dentários; Precisão da Medição Dimensional. CORRESPONDING AUTHOR | • Lauren Oliveira Lima Bohner Department of Prosthodontics, School of Dentistry, University of São Paulo • Av. Prof. Lineu Prestes, 2227 São Paulo, SP, Brazil • 05508-000 E-mail: lauren@usp.br • Received Aug 11, 2017 • Accepted Dec 20, 2017 • DOI http://dx.doi.org/10.11606/issn.2357-8041.clrd.2018.135626 Accuracy of self-perforating impression tray for maxillary dental implant 2 ● Clin Lab Res Den 2017: 1-7 INTRODUCTION Passive fit of an implant-supported dental prosthesis is determinant to provide the long-term success of oral rehabilitation, since a misfit may lead to mechanical complications such as screw loosening, screw fracture or the induction of an internal load on the prosthesis, implants, and bone. Furthermore, biological events have been reported due to the increase in plaque accumulation, resulting in implant failure.1-5 The accuracy of an implant impression is one of the most important factors to determine the fit of restorations, provided that the implant position in the patient̀ s mouth is entirely reproduced in the cast model.6,7,8 Therefore, obtaining an adequate implant impression is an important step to avoid misfit of the implant-supported prosthesis.1,3,5,6,9,10 Currently, the pick-up technique offers the most accurate implant positioning reproduction when the impression is taken of 3 or more implants.11,12 The main disadvantage of the pick-up technique is the large tray holes and long guide screws, which make them difficult to use in mouths with opening restrictions and in the posterior areas.13,14 However, a tray design was developed to make it faster and easier to take impressions of dental implants. The self-perforating tray holds a thin plastic film on the occlusal surface, allowing it to be perforated by the transfers during tray positioning. This feature leads to a clean and precise impression, without excess material on abutments.15 Despite all its advantages, the accuracy of impressions obtained with the self-perforating tray is still controversial.15 Furthermore, there are no reports evaluating the use of this new technology for maxillary impressions. Several studies reported the influence of impression technique and implant position on the accuracy of dental casts.16-23 With this regard, gap measurements are commonly used to evaluate the fit of implants; hence, most studies use the gap width to evaluate the marginal discrepancy.1,9,24,25 Thus, the aim of this study was to evaluate the accuracy of the self-perforating tray for taking an implant impression of the edentulous maxilla when compared with the conventional pick-up technique. The null hypothesis was that there would be no difference in accuracy between the two types of trays for maxillary implant impressions. MATERIAL AND METHODS Sample preparation An acrylic resin master model representing an edentulous maxilla was used in this study. Perforations were made in the region of the canine and first molar (13,16,23,26), in which 4 implants (Straumann, Basel, Switzerland) were fixed with utility wax (Epoxiglass, Diadema, Brazil), as shown in Figure 1. The implant on tooth 13 was kept as reference (IR) for screw tightening and the remaining implants were evaluated (Tooth 16= I1, 23= I2, and 26= I3). Figure 1 | Master model. Bohner L • Marques ADA • Keedi CB • Steagall W • Tortamano Neto P • Clin Lab Res Den 2017: 1-7 ● 3 A cobalt-chromium bar was fabricated using a wax pattern (S-U-Flexible Wax; Schuler-Dental) and cast in cobalt chromium alloy (Remanium 2000; Dentaurum J.P. Winkelstroeter KG). Posteriorly, the bar was screw-retained onto the implants. Toensure an optimal fit, the implants were firstly removed from the model to be individually fixed to the bar. After that, the whole set was fixed to the model using acrylic resin. Subsequently, the entire set was repositioned in the perforations and the implants were fixed to the master model with acrylic resin.15 Impression procedures Two types of impression trays were evaluated (n = 7): Customized open impression trays (G1 Control group) and pre-fabricated selfperforating impression trays (G2 Test group). For the conventional open tray group, individual trays with perforations at the site of the impression copings were fabricated with acrylic resin (Jet, Clássico, São Paulo, Brazil). One tray was used to each impression. Likewise, for the self-perforating group, as the film was perforated after use, a new tray was obtained (Miratray Implant, Hager and Werken GmbH) to each impression (Figure 2). Figure 2 | Self-perforating tray. Firstly, the impression copings (Square transfer, 4.5, Conexão, São Paulo, Brazil) were positioned on the implants and an adhesive (Universal Tray Adhesive, Zhermack, Rome, Italy) was applied to the trays. For both groups, impressions were taken with polyvinyl siloxane (Express, 3M ESPE, St. Paul, USA), manipulated according to the manufacturer’s instructions. After impressiontaking, implant analogs were positioned on the transfer components and dental stone (Type IV, Durone, Dentsply, Petrópolis, Brazil) was poured, after being mixed in accordance with the manufacturer̀ s instructions. Dental casts were stored at 37 °C for 2 weeks. Accuracy analysis For both groups, the metal bar was adapted to each cast model, to analyze the fit accuracy Accuracy of self-perforating impression tray for maxillary dental implant 4 ● Clin Lab Res Den 2017: 1-7 between the bar and the implants. The bar was tightened on implant IR with a torque of 30 Ncm, and the vertical distance between the implant and the bar was measured in implants I1, I2, and I3. The gap was evaluated with a stereomicroscope (40x magnification, Zeiss SV11, Carl Zeiss, Jena, Germany). Measurements were taken in the entire gap and the mean value was calculated and determined as the value of the gap (Figure 3). For each implant, measurements were performed 3 times by the same examiner at intervals of one week. The final gap was defined as the average value of these measurements. The effects of “Tray type” and “Position of implants” were assessed by ANOVA repeated measures and Tukey tests. The T-test was used to evaluate the effect of “Tray type” for each implant. Statistical analysis was performed with the software SPSS 20 (IBM Corp., Chicago, USA) at a level of significance p = 0.05. Figure 3 | Measurement area to determine the mean gap value. RESULTS All data presented variance normality and homogeneity, and were described as mean value ± standard deviation (Table 1, Figure 4). The tray type presented no statistically significant difference (p = 0.192), and no relationship was found between the tray and the implant position (p = 0.224). However, when analyzing the factor “Tray type” individually, implant I1 showed a lower gap value for G1 compared with G2 (p = 0.019). Table 1 | Mean± Standard Deviation (SD) and Confidence of Interval 95% (IC 95%) of the mean gap for customized (G1) and self-perforating (G2) trays according to the different implant locations (I1, I2, I3). I1 I2 I3 p Mean±SD IC 95% Mean±SD IC 95% Mean±SD IC95% G1 73.31±26.01* 49.26; 97.37 149.16±53.90 99.30; 199.02 115.46±73.34 41.63;183.30 >0.05 G2 154.41±74.64 85.37; 223.44 159.45±87.64 78.39; 240.51 109.28±49.18 61.28;155.26 >0.05

A 5-week Non-Surgical Approach towards Denture Induced Hyperplasia

Background Despite the standard approach towards denture-induced hyperplasia being surgery, as elderly population increases the systemic problems are carried along. Thus, surgery might be risky for patients with medical conditions. Objective In this report, a patient with severe inflammatory papillary hyperplasia, medical problems and dental fear was treated with a 5-week nonsurgical protocol. Method Once in a week, the upper denture was relined with a zinc enolic paste, for four weeks. In the fifth week, the denture was relined with fast set polymethyl methacrylate resin instead of zinc enolic paste so that the material would last longer than only a week until the new pair of dentures was manufactured. Results and Conclusion The generated pressure combined with antioxidant and anti-inflammatory properties of the paste led to the elimination of the inflammatory papillary hyperplasia completely, satisfying the patient and allowing the manufacturing of a new set of complete dentures.

Análise crítica das construções protéticas, fixas e removíveis,sobre implantes em pacientes edentados: [revisão]

A osseointegracao e, sem sombra de duvida, a responsavel pelo notavel avanco tecnologico, mudanca deconceitos filosoficos e conducao de planejamentos voltados a reabilitacao oral, como tambem, pela disseminacaoe propagacao dos conhecimentos, interferindo sobremaneira nas demais areas da Odontologia contemporânea.Os implantes osseointegrados sao cada vez mais utilizados para substituir dentes perdidos em varias situacoes, desde a perda de um unico dente ate em casos de completo edentulismo. A reabilitacao de pacientes desdentados com proteses fixas ou overdentures removiveis e um processo complexo e desafiador. Existem fatores cruciais para a decisao de uma protese fixa ou removivel para se obter estetica, fonetica, promover conforto e funcao. Alem disso, o resultado do tratamento esta relacionado a taxa de sobrevivencia dos implantes, a manutencao do osso marginal, a saude do tecido periimplantar, a longevidade dos componentes proteticos e da protese em si. Esse estudo buscou analisar as vantagens e desvantagens das reabilitacoes proteticas sobre implantes, fixas e removiveis, para pacientes totalmente desdentados. (AU) Doubtless, osseointegration is the major responsible for the remarkable technological advance, changing philosophical concepts and guiding treatment plans related to oral rehabilitation. It also contributes to knowledge spread and diffusion, interfering in other areas of contemporary dentistry. Osseointegrated implants are widelyused to replace lost teeth in many situations, since the loss of a single tooth to completely edentulous archcases. Rehabilitation of edentulous patients by using fixed or removable implant-supported prostheses is a complex and challenging procedure. There are crucial factors involved at the decision of whether fixed or removable implant prosthesis should be planned to acquire optimal esthetics, phonetics, comfort, and function. In addition, the treatment result is related to implant survival, crest bone loss, soft tissue health, prosthesiss components longevity and prosthesis longevity itself. The aim of the present study is analyze the advantages and disadvantages of prosthetic rehabilitation of completely edentulous patients with fixed or removable implants. (AU)