Assessment of the reproducibility and precision of milling and 3D printing surgical guides.

BACKGROUND: Technology advancement has rising in the past decade and brought several innovations and improvements. In dentistry, this advances provided more comfortable and quick procedures to both the patient and the dental surgeon, generating less predictability in the final result. Several techniques has been developed for the preparation of surgical guides aiming at the optimization of surgical procedures. The present study aimed to evaluate the reproducibility and precision of two types of surgical guides obtained using 3D printing and milling methods. METHODS: A virtual model was developed that allowed the virtual design of milled (n = 10) or 3D printed (n = 10) surgical guides. The surgical guides were digitally oriented and overlapped on the virtual model. For the milling guides, the Sirona Dentsply system was used, while the 3D printing guides were produced using EnvisionTEC's Perfactory P4K Life Series 3D printer and E-Guide Tint, a biocompatible Class I certified material. The precision and trueness of each group during overlap were assessed. The data were analyzed with GraphPad software using the Kolmogorov-Smirnov test for normality and Student's t test for the variables. RESULTS: The Kolmogorov-Smirnov test showed a normal distribution of the data. Comparisons between groups showed no statistically significant differences for trueness (p = 0.529) or precision (p = 0.3021). However, a significant difference was observed in the standard deviation of mismatches regarding accuracy from the master model (p < 0.0001). CONCLUSIONS: Within the limits of this study, surgical guides fabricated by milling or prototyped processes achieved similar results.

Accuracy of Casts Fabricated by Digital and Conventional Implant Impressions.

The purpose of this study was to compare the accuracy of stereolithographic casts (SCs) with those obtained using conventional implant impressions. An epoxy resin model containing dental implants was used as master model. Dental casts (n = 10) were fabricated through both conventional and digital implant impressions. The conventional casts (CCs), SCs, and the master model were digitized, and the accuracy was determined through a deviation analysis and linear measurements. Data were analyzed using paired Student t test with P < .05. The SCs showed higher deviation at the vestibular area (CC: 41 ± 28.87 µm; SC: 117 ± 36.83 µm) and lingual cusps (CC: 40.70 ± 19.79 µm; SC: 80 ± 42.95 µm) in comparison with CCs. No statistically significant difference was found for linear measurements of conventional and digital casts. The entire-arch accuracy was comparable between casts. However, SCs were less accurate at the cusp level in comparison with CCs.

Comparative analysis of imaging techniques for diagnostic accuracy of peri-implant bone defects: a meta-analysis.

OBJECTIVE: The aim of this study was to systematically review the literature regarding diagnostic accuracy of imaging techniques in detecting peri-implant bone defects. STUDY DESIGN: The search was performed in 8 electronic databases from April to May 2016 and updated in September 2016. Studies that assessed imaging techniques to detect peri-implant bone defects were analyzed. RESULTS: The search yielded 680 articles published from 1991 to 2016. Of these, 12 studies were considered eligible for this review. The selected studies evaluated the use of cone beam computed tomography (CBCT), intraoral radiography (IR), computed tomography, and panoramic radiography. The sensitivity for CBCT was 59%, whereas the specificity was 67%. For IR, the sensitivity was 60%, and the specificity was 59%. Area under the curve values in receiver operating characteristic (ROC) analysis were 69% for CBCT and 63% for IR. For CBCT, the highest value for positive predictive value was 0.94, negative predictive value was 0.98, positive likelihood ratio was 21.3, and negative likelihood ratio was 1.28. For IR, the highest positive predictive value was 1.0, negative predictive value 1.0, positive likelihood ratio 50.0, and negative likelihood ratio 0.70. The highest diagnostic odds ratio was 80 for CBCT and 4.45 for IR. No conclusion could be drawn for additional techniques. CONCLUSIONS: Both CBCT and IR showed a clinically acceptable performance for assessing peri-implant bone defects.

Taxa de sobrevivência de implantes e biomateriais no levantamento do seio maxilar com pneumatização significativa: um estudo retrospectivo com 79 pacientes, durante seis meses a dez anos / Survival rate of immediate dental implants and biomaterials after large sinus lifting procedures: a retrospective study on 79 patients with a 6-month to 10-year follow-up

Objetivo: avaliar retrospectivamente a taxa de sucesso de implantes e biomateriais após o levantamento do seio maxilar. Material e métodos: foram utilizados prontuários de pacientes tratados entre 1998 e 2014, incluídos os que possuíam rebordo maxilar com altura menor do que 5 mm. Todos os procedimentos de enxertia foram realizados com instalação de implante de forma mediata e acesso ao seio maxilar pela janela óssea lateral, colocação do biomaterial, membrana e sutura. Resultados: foram analisados 79 pacientes, tendo sido utilizados dois biomateriais. O tempo de reavaliação variou de seis meses a dez anos. Nos dados de altura óssea radiográfica antes e depois do procedimento (70 implantes, 36 pacientes), houve um aumento médio de altura na região do seio maxilar com o Bio-Oss de 17,23 mm e com o Orthogen de 13,12 mm (p < 0,05), sendo a média geral de 15,17 mm. Na relação sobrevida do implante e enxerto utilizado (92 implantes, 43 pacientes), os valores foram de 96,8% (autógeno) e 98,3% (autógeno + biomaterial). Conclusão: os resultados permitiram concluir que tanto os enxertos autógenos como os biomateriais são alternativas viáveis para os seios maxilares com grande pneumatização.

Objective: to retrospectively evaluate the success rate of implants and biomaterials after maxillary sinus lift. Material and methods: records of patients treated between 1998 and 2014 were used, including those with maxillary ridge height less than 5 mm. All grafting procedures were performed with implant placement and access to the maxillary sinus through the lateral bony window, placement of the biomaterial, membrane and suture. Results: 79 patients were analyzed and two biomaterials were used. The follow-up period ranged from six months to ten years. In the radiographic bone height data before and after the procedure (70 implants, 36 patients), there was a mean increase in height in the maxillary sinus region with the Bio-Oss of 17.23 mm and with the Orthogen of 13.12 mm (p < 0.05), the overall mean being 15.17 mm. Regarding implant and graft survival (92 implants, 43 patients), the values were 96.8% (autogenous) and 98.3% (autogenous + biomaterial). Conclusion: both autogenous grafts and biomaterials are viable alternatives for the maxillary sinuses with great pneumatization.

Accuracy comparison of guided surgery for dental implants according to the tissue of support: a systematic review and meta-analysis.

AIM: To systematically assess the current dental literature comparing the accuracy of computer-aided implant surgery when using different supporting tissues (tooth, mucosa, or bone). MATERIAL AND METHODS: Two reviewers searched PubMed (1972 to January 2015) and the Cochrane Central Register of Controlled Trials (Central) (2002 to January 2015). For the assessment of accuracy, studies were included with the following outcome measures: (i) angle deviation, (ii) deviation at the entry point, and (iii) deviation at the apex. RESULTS: Eight clinical studies from the 1602 articles initially identified met the inclusion criteria for the qualitative analysis. Four studies (n = 599 implants) were evaluated using meta-analysis. The bone-supported guides showed a statistically significant greater deviation in angle (P < 0.001), entry point (P = 0.01), and the apex (P = 0.001) when compared to the tooth-supported guides. Conversely, when only retrospective studies were analyzed, not significant differences are revealed in the deviation of the entry point and apex. The mucosa-supported guides indicated a statistically significant greater reduction in angle deviation (P = 0.02), deviation at the entry point (P = 0.002), and deviation at the apex (P = 0.04) when compared to the bone-supported guides. Between the mucosa- and tooth-supported guides, there were no statistically significant differences for any of the outcome measures. CONCLUSIONS: It can be concluded that the tissue of the guide support influences the accuracy of computer-aided implant surgery.

Bone defect rehabilitation using lyophilized bone preshaped on a stereolithographic model.

Bone grafting provides ideal conditions to the patient's rehabilitation with dental implants. In addition, prototyped tridimensional models allow the surgical procedure to be simulated and enable important anatomic structures to be visualized. To present a bone defect rehabilitated with xenogenic bone preshaped on a stereolithographic model and the follow-up after 7 years of treatment. The present case report describes a bone defect rehabilitated with a lyophilized bone block preshaped on a stereolithographic model. The patient, a 56-year-old woman, was referred to the dental office presenting a bone defect in the anterior maxilla. Bone regeneration intervention was performed with xenogenic grafting and barrier membrane. The follow-up of the postoperative period and after 7 years is presented. After 7 years, the tomographic exam showed the maintenance of bone at the grafted site, representing the long-term success of the treatment.

Fabrication of lithium silicate ceramic veneers with a CAD/CAM approach: a clinical report of cleidocranial dysplasia.

The fabrication of minimally invasive ceramic veneers remains a challenge for dental restorations involving computer-aided design and computer-aided manufacturing (CAD/CAM). The application of an appropriate CAD/CAM protocol and correlation mode not only simplifies the fabrication of ceramic veneers but also improves the resulting esthetics. Ceramic veneers can restore tooth abnormalities caused by disorders such as cleidocranial dysplasia, enamel hypoplasia, or supernumerary teeth. This report illustrates the fabrication of dental veneers with a new lithium silicate ceramic and the CAD/CAM technique in a patient with cleidocranial dysplasia.

Caracterização de um novo arcabouço de hidroxiapatita bifásica com a adsorção de fluoreto / Characterization of a new scaffold biphasic hydroxiapatite with fluoride adsorption

As hidroxiapatitas (HA) são amplamente utilizadas como biomateriais osteocondutores, mas não possuem propriedades osteoindutoras e osteogênicas. O fluoreto, por sua vez, quando presente no meio em doses adequadas (da ordem de 10-5 M), é capaz de aumentar a proliferação de osteoblastos e a atividade da fosfatase alcalina. Assim, o objetivo do presente estudo foi modificar um biomaterial existente, constituído por HA bifásica (70% HA + 30% β-TCP) porosa, pela adsorção de fluoreto. A capacidade de liberação de fluoreto deste material para meio de cultura osteogênico foi também avaliada. Foi ainda feita caracterização físicoquímica do material com fluoreto adsorvido, em comparação ao material original (FTIR, DRX e MEV). Para os ensaios de adsorção de fluoreto, soluções com diferentes concentrações deste elemento, na forma de NaF, foram adicionadas à HÁ bifásica na proporção de 10 g de HA por 50 mL de solução contendo fluoreto. Os testes foram feitos em duas etapas. Na primeira etapa, as concentrações de fluoreto empregadas variaram entre 100 e 2000 ppm e foi feita incubação por 3, 6, 18 ou 24 h, em temperatura ambiente, sob agitação constante. Após estes intervalos de tempo, removeu-se o sobrenadante e colocou-se o restante na estufa a 40oC, até a completa secagem dos grânulos. Os mesmos foram armazenados para posterior quantificação de fluoreto adsorvido, que foi feita com o eletrodo, após difusão facilitada por exametildisiloxano. Na segunda etapa, as concentrações de fluoreto empregadas variaram entre 0,625 e 80 ppm, sendo feita incubação por 24 ou 48 h. Para a avaliação da liberação de fluoreto da HA adsorvida, as amostras de HA com fluoreto adsorvido foram incubadas à temperatura ambiente com meio de cultura α-MEM, na proporção de 10 g de HA por 50 mL de meio, sob agitação, por 3, 6, ou 24 h e o sobrenadante foi coletado para quantificação de fluoreto. Foi observada uma relação dose- resposta entre a concentração de fluoreto que se adsorveu à HA...

Hydroxyapatites (HA) are broadly employed as osteoconductive biomaterials, but they do not possess osteoinductive or osteogenic properties. Fluoride, when present in the environment in appropriate doses (around 10-5 M) is able to increase the proliferation of osteoblastos and the activity of alcaline phosphatase. Thus, the aim of the present study was to modify an existing biomaterial (biphasic HA, containing 70% HA and 30% β-TCP), through the adsorption of fluoride. The ability of this material to release fluoride for osteogenic culture medium was also evaluated. The biomaterial containing adsorbed fluoride was characterized physic-chemically (FTIR, DRX and SEM), in comparison to its counterpart without adsorbed fluoride. For the fluoride adsorption experiments, solutions with different fluoride concentrations (as NaF) were added to biphasic HA (10 g HA : 50 mL fluoridecontaining solution). Tests were carried out in 2 stages. In the first stage, fluoride concentrations used ranged between 100 and 2000 ppm. Incubation was done for 3, 6, 18 or 24 h, at room temperature, under constant agitation. After incubation, supernatant was removed and the pellets were allowed to dry at 40oC. The resulting material was stored for subsequent fluoride analysis that was done with the electrode, after examethyldisiloxane-facilitated diffusion. In the second stage, the fluoride concentrations ranged between 0.625 and 80 ppm and incubation was carried out for 24 or 48 h. For the evaluation of the release of adsorbed fluoride, samples of HA containing adsorbed fluoride were incubated in α-MEM medium at room temperature (10 g HA : 50 mL medium), under agitation, for 3, 6 or 24 h. Supernatant was collected for fluoride quantification. A dose- response relationship was observed between the concentration of fluoride that adsorbed to HA and the fluoride concentration in the incubation solutions. The time of incubation did not change the concentration of adsorbed fluoride...