Prospective Evaluation of Bone Remodeling in Full-Arch Rehabilitations with Morse Taper Implants: A Case Series Study with One-Year Follow-Up.

This case series study evaluated the survival, success rate and marginal bone remodeling of Morse taper hydrophilic implants placed for full-arch rehabilitations over a 1-year follow-up period. Ten patients in need of maxillary and/or mandibular full-arch rehabilitation were selected. Sixty-six Morse taper implants and sixty-six abutments were inserted. All implants were placed using a surgical flap approach without bone regeneration and were immediately loaded with definitive prostheses according to the passive fitting technique. The patients underwent clinical and radiographic follow-up at different postoperative periods: T0 = immediate (up to 1 month after surgery); T1 = 3-4 months after surgery; T2 = 6-8 months after surgery; and T3 = 1 year after surgery. The survival and success rate of the implants and the marginal bone remodeling were evaluated. Normal distribution of the outcomes was verified by Kolmogorov-Smirnov tests. Therefore, changes in vertical and horizontal marginal bone levels were assessed with paired t-tests. Results were considered significant for P < 0.05. Survival and success rates of 100% and 92.4%, respectively, were observed. Statistically significant vertical bone level changes were shown for all periods. From T0 to T3, there was a mean difference in vertical bone loss of -1.02 mm on the mesial surface and of -0.93 mm on the distal surface, for horizontal bone loss in the same period, it was observed mean changes of -0.14 mm on the mesial surface and -0.09 mm on the distal surface. This 1-year case series follow-up of immediate full-arch rehabilitation, using one-step hybrid passive fitting supported by four to six hydrophilic tapered implants, suggests predictability with high survival and success rates in edentulous patients.

Retrospective Multivariate Clinical Analysis of 2707 Dental Implants with Hydrophilic and Hydrophobic Surfaces: Survival Rates after Up to 5 Years.

The aim of this retrospective study was to evaluate the long-term predictability of treatment using implants with hydrophobic and hydrophilic surfaces, according to clinical parameters and survival rates. Records from all patients who received dental implants between January 2013 and December 2014 at ILAPEO College were fully evaluated by two graduate dentists. Records with incomplete or unclear data were excluded from the study. The variables evaluated were demographic data, design of implants and prosthetic components, type of loading, data related to the patients' general health, and survival of implants and prostheses. The final retrospective sample comprised 776 patients with 2707 implants, with up to 5 years of follow-up. Survival rates of implants and prostheses were 97.93% and 98.77%, respectively. Implants with hydrophobic (97.87%) and hydrophilic (98.34%) surfaces exhibited similar survival rates. Considering the different types of loading, there was no statistically significant difference between loading protocols regarding implant survival rates. Unsuitable healing capacity, uncooperative and not motivated patient, loss of prosthesis, and peri-implant bone loss were confirmed statistically to be factors that may contribute to implant loss, according to hazard ratio and odds ratio. The present study showed similar and high overall survival rates for implant with both types of surfaces, in the long term. The surface treatment, implant model and loading protocol had no significant influence on implant loss. Therefore, the evaluated implant systems were able to offer a high predictability for both hydrophobic and hydrophilic implants.

Evaluation of the Mechanical Reliability of Different Implant-Abutment Connections for Single Crowns According to the ISO 14801 Fatigue Test Protocol.

PURPOSE: The aim of this in vitro study was to evaluate the mechanical behavior regarding dynamic fatigue of different implant-abutment connections and the unitary indication of abutments for all regions of the mouth. MATERIALS AND METHODS: This experimental study developed according to international standards (ISO 14801:2007) was performed using five types of implants and abutments: G1-external hex smart implant and 17-degree universal abutment (EHS); G2-cortical external hex implant and 17-degree universal abutment (EHTi); G3-internal hex implant and 30-degree universal abutment (IH); G4-Morse taper implant (11.5 degrees) and 17-degree universal abutment (MT11.5); and G5- Morse taper implant (16 degrees) and 30-degree universal abutment (MT16). A 15-Hz cyclic loading was applied to the specimens with the maximum number of cycles set at 5 × 106. Success was defined when three samples supported 5 million cycles without failure. The maximum load supported from each group after dynamic loading was recorded. The Spearman correlation and the Lowess method were used to analyze the correlation between the number of cycles and the applied load, and the Kruskal-Wallis and Nemenyi tests were used for comparison between the abutments when reaching 5 million cycles. RESULTS: There was a negative correlation (r < 0.00) and significant difference (P < .05) between the number of cycles and the load for each type of implant and abutment. The load values supported by each group after cyclic loading to achieve 5 million cycles were as follows: EHS, 225 N; EHTi, 215 N; IH, 220 N; MT11.5, 210 N; and MT16, 240 N. The MT16 implant-abutment assembly presented a significantly higher load (P = .024) than the MT11.5 implant-abutment assembly. CONCLUSION: All implant-abutment connections investigated in this study resisted average occlusal force values reported as acceptable in the literature and may be indicated for any region of the mouth.

Full arch rehabilitation in patients with atrophic upper jaws with zygomatic implants: a systematic review.

BACKGROUND: The main objective of this systematic review was to present the outcomes of the treatment with zygomatic implants (ZIs) in the rehabilitations of atrophic upper jaw. FINDINGS: An electronic database search in PubMed, along with a manual search, taking into account language and study period, was performed by two observers; any type of clinical trial and series that included the use of ZIs was used. In the search strategy, the following search terms were used: zygom* AND dental (Implant OR implants) AND edentulous NOT (biomechanic* OR finite element) NOT cadaver. The search was limited to English language, full text, and humans. Literature reviews and clinical case reports were not considered. Forty-two articles published between March 2003 and April 2019 were included in this analysis. The cases of 1247 patients were recovered; these patients received 2919 ZIs. Fifty-two ZIs were removed during the follow-up time. The survival rate of these implants was 98.22%, with a minimum follow-up of 1 month and a maximum of 228 months. Different surgical techniques were used to place ZIs; however, the intrasinusal technique was the most used (23 studies). Post-surgical sinusitis was the most common complication reported in the studies (39 cases). CONCLUSIONS: Based on this review, ZIs were commonly used for rehabilitation of patients with atrophic upper jaw. The survival rates presented were high, and the surgical technique is dependent on the professional experience and the local anatomy. However, it needed additional clinical evidence on bone resorption, esthetic outcomes, and physiological characteristics.

Biomechanical behavior of three different types of internal tapered connections after cyclic and static loading tests: experimental in vitro.

BACKGROUND: In the long-term success of a dental implant, the reliability and stability of the implant-abutment interface are important. Studies of maximum force of dental implants with different loading values have been used. This study aims to evaluate the influence of the oblique cyclic loading on the maximum force supported in one-piece and two-piece abutments installed on internal tapered implants. FINDINGS: Sixty implants and sixty prosthetic abutments were divided into six groups (n = 10): G1 and G2 (two-piece abutments with 16°), G3 and G4 (two-piece abutments with 11.5°), and G5 and G6 (one-piece abutments with 11.5°). A 2-Hz cyclic loading was applied to specimens of G2, G4, and G6, with a number of cycles of 2,400,000. All specimens were inclined by 30° from the vertical axis, and a vertical loading was applied over the tapered connections (ISO 14801). Then, the maximum force was tested by applying a static compression load on the specimens of the 6 groups tested (30°) at a rate of 0.5 mm/s. Statistical analysis was performed using the Shapiro-Wilk (p > 0.05) and Levene (p = 0.789) tests to determine if the data presented homoscedasticity and the Tukey test for multiple comparisons. Tukey test showed that the maximum force supported by G1 and G2 was not affected by the cyclic load, while in G3 and G4 it decreased significantly when subjected to the cyclic load. The G5 and G6 had a significant increase in maximum force supported when subjected to cyclic load. CONCLUSIONS: Cyclic loading influenced the maximum force supported of G4 and G6 but did not influence G2.

Influence of Screw Surface Treatment on Retention of Implant-Supported Fixed Partial Dentures.

The aim of this study was to assess the effect of a diamond-like carbon (DLC) coating on the removal torque of prefabricated implant screws after cyclic loading. Four groups with two crowns supported by two implants (n = 5) were obtained according to splinted and nonsplinted prosthesis, using titanium or DLC screws (splinted crowns with titanium screw [STi], splinted crowns with DLC screw [SC], nonsplinted crowns and titanium screw [NSTi], and nonsplinted crowns and DLC screw [NSC]). The prosthetic screws were tightened at 32 Ncm and retightened, and the specimens were submitted to 106 mechanical cycles (4 Hz/98 N). After cyclic loading, loosening torque was evaluated, and the final measurements were performed. Data were analyzed by two-way analysis of variance and Tukey's test (α = .005). There was statistically significance in the interaction of screw × splinting (P = .003). For the group that used titanium screws, NSTi showed smaller removal torque compared with STi. It was concluded that the use of the DLC coating screws in nonsplinted prosthesis maintain the torque after cyclic loading.

Analysis of the properties of dental cements after exposure to incubation media containing Streptococcus mutans.

AIM: Indirect restorations are increasingly used in dentistry, and the cementation interface is possibly the most critical region of the work. The objective of the present work was to evaluate the influence of exposure to a culture medium containing S. mutans on the hardness and solubility of four different cementing agents (zinc phosphate, glass ionomer, glass ionomer modified with resin and resin cement). MATERIALS AND METHODS: Test specimens composed of these cements were exposed for 30 days in a culture medium containing S. mutans. After leaching, the test materials were assessed in terms of their solubility (loss of mass) and Knoop (KHN) microhardness. Changes in surface morphology were identified using scanning electron microscopy (SEM). RESULTS: The resin cement showed no significant solubility and its hardness increased following exposure and leaching, while the zinc phosphate cement was the most soluble and its hardness decreased after exposure to the culture medium. SEM analyses identified morphological alterations on the surfaces of the test materials that were compatible with the solubility results. CONCLUSION: It is concluded that resinous cements perform better than water-based cements when exposed to acidic conditions. CLINICAL SIGNIFICANCE: The effects of acids from Streptococcus mutans can interfere with the efficiency and properties of some cements used for fixation of indirect restorations, exposed to the buccal environment.