Clinical and tomographic comparison of dental implants placed by guided virtual surgery versus conventional technique: A split-mouth randomized clinical trial.

AIM: Our objective was to compare guided virtual surgery to conventional surgery in terms of angular deviation of single dental implants placed in the posterior mandible. MATERIALS AND METHODS: Patients with bilateral homologous single teeth missing in the posterior mandible were eligible for this split-mouth randomized clinical trial. Cone beam computed tomography (CBCT) was performed for virtual planning of implant position and manufacturing of the stereolithographic guides. One week after the surgery, a second CBCT scan was superimposed to the initial planning. Primary endpoint was the angular deviation between virtual and clinical implant position. Secondary endpoints were linear deviations and patient-reported outcomes collected with a questionnaire. RESULTS: Data from 12 patients were available for analysis. Angular deviation was significantly lower using stereolithographic guides as compared to conventional guides (2.2 ± 1.1° vs. 3.5 ± 1.6°, p = .042). Linear deviations were similar for both techniques in the coronal (2.34 ± 1.01 vs. 1.93 ± 0.95 mm) and apical (2.53 ± 1.11 vs. 2.19 ± 1.00 mm) dimensions (p Ëƒ .05). The selection of the surgical technique had no significant impact on the patient-reported outcomes. CONCLUSION: Our data suggest that the angular discrepancy between the virtual and the clinical implant position is slightly lower when using stereolithographic guides as compared to conventional guides.

Influence of immediate/delayed implant placement and implant platform on the peri-implant bone formation.

AIM: To determinate the influence of the timing and position of the implant placement, as well as the presence and absence of a buccal gap, associated with different implant platforms on bone formation around implants. METHODS AND MATERIALS: In a first surgical stage, two premolars in one side of the mandibular arch of 07 mongrel dogs were extracted. After a 120-day healing period, a second-stage surgery was performed, in which a full flap was raised and two implants were installed. At this same stage, two contralateral premolars were extracted and two immediate implants were placed into the fresh sockets, through the "palatal approach technique" without flap elevation, totaling four implants per animal. The 28 installed implants constituted groups according to the timing (Immediate or delayed) of placement and the type of surface treatment. After 4 months, samples were collected and histomorphometric analysis was performed to determinate buccal surface BIC, lingual surface BIC, total BIC, buccal area, and lingual area of all implants. Kruskal-Wallis and pared Wilcoxon (P < 0.05) tests were performed for statistical analysis. RESULTS: After 4-month healing period, the groups of immediate implants presented better BIC scores, mainly on the buccal surface. Data also suggest better bone area formation around the implants of these same groups. Concerning the type of implant platform, better results were found using Morse taper. CONCLUSION: The flapless technique with "palatal approach," Morse taper implants, and immediate implant placement all have favorable influence on the bone formation around the implants.

Optical Behavior of Zirconia-Based Restorations Over Teeth and Implants in the Esthetic Zone: A Clinical Report.

While various zirconia-based alternatives are available today for the restoration of teeth and implants in the esthetic zone, each treatment approach could result in different optical behavior. To clinically demonstrate these differences, this case report describes a rehabilitation in the esthetic zone using several options of teeth- and implant-supported restorations. Conventional veneered zirconia crowns, high-translucent monolithic zirconia crowns, and minimally veneered high-translucent zirconia crowns were proposed and assessed under different light sources before cementation. The patient and clinical team achieved consensus on the minimally veneered high-translucent zirconia crowns, which were then cemented and have performed well over both tooth and implant substrates.

Biofilm Formation on Different Materials Used in Oral Rehabilitation.

The aim of this study was to evaluate the density and the morphological aspects of biofilms adhered to different materials applied in oral rehabilitation supported by dental implants. Sixty samples were divided into four groups: feldspar-based porcelain, CoCr alloy, commercially pure titanium grade IV and yttria-stabilized zirconia. Human saliva was diluted into BHI supplemented with sucrose to grow biofilms for 24 or 48 h. After this period, biofilm was removed by 1% protease treatment and then analyzed by spectrophotometry (absorbance), colony forming unit method (CFU.cm-2) and field-emission guns scanning electron microscopy (FEG-SEM). The highest values of absorbance and CFU.cm-2 were recorded on biofilms grown on CoCr alloys when compared to the other test materials for 24 or 48 h. Also, FEG-SEM images showed a high biofilm density on CoCr. There were no significant differences in absorbance and CFU.cm-2 between biofilms grown on zirconia, porcelain and titanium (p<0.05). Microbiological assays associated with microscopic analyses detected a higher accumulation of oral biofilms on CoCr-based materials than that on titanium or zirconia that are used for prosthetic structures.

Biofilm Formation on Different Materials Used in Oral Rehabilitation

Abstract The aim of this study was to evaluate the density and the morphological aspects of biofilms adhered to different materials applied in oral rehabilitation supported by dental implants. Sixty samples were divided into four groups: feldspar-based porcelain, CoCr alloy, commercially pure titanium grade IV and yttria-stabilized zirconia. Human saliva was diluted into BHI supplemented with sucrose to grow biofilms for 24 or 48 h. After this period, biofilm was removed by 1% protease treatment and then analyzed by spectrophotometry (absorbance), colony forming unit method (CFU.cm-2) and field-emission guns scanning electron microscopy (FEG-SEM). The highest values of absorbance and CFU.cm-2 were recorded on biofilms grown on CoCr alloys when compared to the other test materials for 24 or 48 h. Also, FEG-SEM images showed a high biofilm density on CoCr. There were no significant differences in absorbance and CFU.cm-2 between biofilms grown on zirconia, porcelain and titanium (p<0.05). Microbiological assays associated with microscopic analyses detected a higher accumulation of oral biofilms on CoCr-based materials than that on titanium or zirconia that are used for prosthetic structures.

Resumo O objetivo deste estudo foi avaliar a densidade e os aspectos morfológicos dos biofilmes aderidos a diferentes materiais aplicados em reabilitação oral sobre implantes dentários. Sessenta amostras foram divididas em quatro grupos: porcelana à base de feldspato, liga de CoCr, titânio grau IV comercialmente puro e zircônia estabilizada com ítrio. Saliva humana diluída em BHI foi suplementada com sacarose para possibilitar a formação de biofilme por 24 e 48 h. Após este período, o biofilme foi removido utilizando protease a 1% e, em seguida, analisada por espectrofotometria (absorbância), unidades formadoras de colônia (CFU.cm-2) e microscopia eletrônica de varredura (MEV). Os valores mais elevados de absorbância e CFU.cm-2 foram encontrados em ligas de CoCr quando comparado com os outros materiais testados. Os resultados obtidos foram semelhantes nos biofilmes formados sobre titânio e zircônia durante 24 e 48 h (p<0,05). As análises microbiológicas e microscópicas demostraram uma maior tendência ao acúmulo de biofilmes orais sobre estruturas protéticas baseadas em CoCr quando comparadas com porcelana feldspática, titânio ou zircônia.