Comparative in vitro evaluation of microgap in titanium stock versus cobalt-chrome custom abutments on a conical connection implant: Effect of crown cementation and ceramic veneering.

OBJECTIVE: To compare the implant-abutment connection microgap between computer-aided design and computer-aided manufacturing (CAD/CAM) milled or laser-sintered cobalt-chrome custom abutments with or without ceramic veneering and titanium stock abutments with or without crown cementation. MATERIAL AND METHODS: Six groups of six abutments each were prepared: (1) CAD/CAM cobalt-chrome custom abutments: milled, milled with ceramic veneering, laser-sintered, and laser-sintered with ceramic veneering (four groups: MIL, MIL-C, SIN, and SIN-C, respectively) and (2) titanium stock abutments with or without zirconia crown cementation (two groups: STK and STK-Z, respectively). Abutments were screwed to the implants by applying 30 Ncm torque. All 36 samples were sectioned along their long axes. The implant-abutment connection microgap was measured using scanning electron microscopy on the right and left sides of the connection at the upper, middle, and lower levels. Data were analyzed using the Kruskal-Wallis test (p < .05). RESULTS: Mean values (µm) of the microgap were 0.54 ± 0.44 (STK), 0.55 ± 0.48 (STK-Z), 1.53 ± 1.30 (MIL), 2.30 ± 2.2 (MIL-C), 1.53 ± 1.37 (SIN), and 1.87 ± 1.8 (SIN-C). Although significant differences were observed between the STK and STK-Z groups and the other groups (p < .05), none were observed between the milled and laser-sintered groups before or after ceramic veneering. The largest microgap was observed at the upper level in all groups. CONCLUSIONS: Titanium stock abutments provided a closer fit than cobalt-chrome custom abutments. Neither crown cementation nor ceramic veneering resulted in significant changes in the implant-abutment connection microgap.

A Radiographic and Clinical Comparison of Immediate vs. Early Loading (4 Weeks) of Implants with a New Thermo-Chemically Treated Surface: A Randomized Clinical Trial.

Background: Implant dentistry has evolved over time, resulting in better treatment outcomes for both patients and clinicians. The aim of this trial was to test whether the immediate loading of implants with a platform-switching design influences the marginal bone level, compared to four-week loading, after one year of follow-up. Moreover, a comparison of clinical data regarding implant survival, implant stability, and patient-reported outcome measures (PROMs) was conducted. Methods: Klockner® VEGA® implants with a ContacTi® surface were placed in partially edentulous patients in the posterior areas. Group A received an immediately loaded prosthesis (one week) and Group B received an early-loaded prosthesis (four weeks). All abutments were placed at the time of surgery. Radiographic and clinical data were recorded. Results: Twenty-one patients were treated (35 implants). No implants were lost during the study. The final marginal bone level did not show differences between groups. The bone loss at 12 months at the implant level was 0.00 mm for both groups (median). The final implant quotient stability (ISQ) values did not differ between groups (median 73 and 70.25), nor did the other clinical parameters or PROMs. Conclusions: The results suggest that neither of the loading protocols with the implants used influenced the marginal bone level-not the osseointegration rate, clinical conditions, or PROMs.

Influence of Implant Design and Under-Preparation of the Implant Site on Implant Primary Stability. An In Vitro Study.

The aim of this study was to evaluate the effects of different implant sites an under-preparation sequence associated with two different implant designs on implant primary stability measured by two parameters: insertion torque (IT) and implant stability quotient (ISQ). It used two different implants: one cylindrical as a control and another one with a tapered design. The implants were inserted in type III fresh humid bovine bone and four drilling sequences were used: one control, the one proposed by the implant company (P1), and three different undersized (P2, P3 and P4). P2 was the same as P1 without the cortical drill, P3 was without the last pilot drill and P4 was without both of them. The sample size was n = 40 for each of the eight groups. Final IT was measured with a torquemeter and the ISQ was measured with Penguin resonance frequency analysis. Results showed that both ISQ and IT have a tendency to increase as the preparation technique reduces the implant site diameter when compared with the standard preparation, P1. The preparations without cortical drill, P2 and P4, showed the best results when compared with the ones with a cortical drill. Tapered implants always showed higher or the same ISQ and IT values when compared with the cylindrical implants. Giving the limitations of this study, it can be concluded that reducing implant preparation can increase IT and ISQ values. Removing the cortical drill and the use of a tapered design implant are also effective methods of increasing primary implant stability.

In vitro evaluation of the type of implant bed preparation with osteotomes in bone type IV and its influence on the stability of two implant systems.

OBJECTIVES: 1) To evaluate and compare the stability of two types of implants in an animal model after preparing the implant bed with various sequences of osteotomes in bone type IV. 2) To evaluate the hypothesis of whether or not the sequence of using osteotomes influences the primary implant stability. MATERIAL AND METHOD: We selected bone from cow ribs, which in its cross section (the most medullar area of the bone) would be equivalent to a type IV human bone. We used fifteen ribs, in which six implant beds were prepared in each rib block using different preparation protocols for seating three conical Swiss Plus SPB implants of 3.7 x 10 mm versus three MK III parallel wall implants of 4 x 10 mm.Three preparations, each with a diameter, were made for the implants, using osteotomes that progressively increased the diameter of the implant bed. In the first preparation, the complete sequence of osteotomes was used; in the second preparation, the last osteotome was left out; and in the third preparation, the implant was placed after only passing through the first osteotome. Once the implants were seated, we proceeded to evaluate the stability (Osstell ISQ-value). The locations were randomly chosen (by a coin toss). RESULTS AND STATISTICAL ANALYSIS: We performed a statistical analysis of the ISQ values that were obtained during the different preparations carried out for the Mk III and Swiss Plus implants. The average range and standard deviation were calculated. The hypothesis was compared by a two-way variance analysis (type of implant/ different sequences of preparing the implant bed). It was considered significant for a p <0.05. The statistical results obtained for the values of the Mk III implant were significant (p = 0.042). CONCLUSIONS: The results of this in vitro study conclude that the tapered shape provides more primary stability to the implant and suggest that a short sequence of osteotomes in bone type IV provide more primary stability than the complete sequence.

In vitro evaluation of the type of implant bed preparation with osteotomes inbone type IV and its influence on the stability of two implant systems

Objectives: 1) To evaluate and compare the stability of two types of implants in an animal model after preparingthe implant bed with various sequences of osteotomes in bone type IV. 2) To evaluate the hypothesis of whetheror not the sequence of using osteotomes influences the primary implant stability.Material and Method: We selected bone from cow ribs, which in its cross section (the most medullar area of thebone) would be equivalent to a type IV human bone. We used fifteen ribs, in which six implant beds were preparedin each rib block using different preparation protocols for seating three conical Swiss Plus SPB implants of 3.7 x10 mm versus three MK III parallel wall implants of 4 x 10 mm.Three preparations, each with a diameter, weremade for the implants, using osteotomes that progressively increased the diameter of the implant bed. In the firstpreparation, the complete sequence of osteotomes was used; in the second preparation, the last osteotome was leftout; and in the third preparation, the implant was placed after only passing through the first osteotome. Once theimplants were seated, we proceeded to evaluate the stability (Osstell® ISQ-value). The locations were randomlychosen (by a coin toss).Results and statistical analysis: We performed a statistical analysis of the ISQ values that were obtained during thedifferent preparations carried out for the Mk III and Swiss Plus implants. The average range and standard deviationwere calculated. The hypothesis was compared by a two-way variance analysis (type of implant/ differentsequences of preparing the implant bed). It was considered significant for a p <0.05. The statistical results obtainedfor the values of the Mk III implant were significant (p = 0.042). Conclusions: The results of this in vitro study conclude that the tapered shape provides more primary stability to the implant and suggest that a short sequence of osteotomes in bone type IV provide more primary stability than the complete sequence (AU)

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In vitro evaluation of the influence of the cortical bone on the primary stabilityof two implant systems

Aims: Immediate loading has become a predictable option for treatment, while one of the main requirements forits implementation is obtaining appropriate primary stability in implants. With that aim, conical implants are commerciallyavailable, since, according to specialized literature, they provide greater stability. One of the methodsto measure implant stability which has evolved to further stages is resonance frequency analysis (RFA). In thepresent paper we attempt to evaluate the influence of the cortical bone on the primary stability of two implants ofsimilar diameter and length.Study design: 15 fresh cow ribs were selected and six different implant beds were prepared in each. These preparationscorresponded to two different implant systems: A Swiss Plus from Zimmer Dental® and an Mk IV from NobelBiocare®. Two drilling protocols were used for soft bone, hard bone and bone without cortical. After preparingthe beds, the implants were placed and implant primary stability was measured with the Osstell® mentor.Results: Higher ISQ (Implant Stability Quotient) values were observed for both implant systems when the corticalbone is maintained than when it is eliminated, the difference being statistically significant in the case of Mk IVimplants.Conclusions: The results from this study show the importance of preserving cortical bone during drilling in orderto obtain greater primary stability (AU)

El tratamiento de la periimplantitis en base a protocolos científicos. Revisión de la literatura / Periimplantitis treatment on the basis of scientific protocols. Literature review

La comprensión de la patología alrededor de los implantes, no ha sido constatada en modelos experimentales hasta muy recientemente. A raíz de estos estudios se ha podido evidenciar el factor infeccioso como causa principal en estas patologías. Por otro lado, y al margen de estos hallazgos, se han planteado una serie de protocolos sobre modelos clínicos y experimentales en relación a la conducta terapéutica a seguir a la hora de abordar el tratamiento clínico de la periimplantitis. El presente artículo se centra en la recopilación y análisis de la evidencia publicada a este respecto. (AU)