Use of Acid for Oxide Layer Removal of Overcast UCLA Abutments: Influence on Fit and Roughness.

PURPOSE: The objective of this study was to evaluate the influence of the oxide layer removal procedure using acid on the roughness and internal fit of overcast universal castable long abutments (UCLAs) for a taper connection. MATERIALS AND METHODS: For this, maxillary first premolars were waxed on the plastic sleeve of 15 UCLAs with a premachined interface. The specimens were overcast using the NiCr alloy, and the frameworks were randomly distributed to undergo one of two different oxide layer removal methods: blasting with 100-µm particles of aluminum oxide at 0.60-MPa pressure or bathing for 5 hours in 0.5% hydrofluoric acid. The surface roughness was evaluated by a light interferometer at the subcritical contour of each abutment. Next, the frameworks were attached to the respective analogs for internal fit evaluation. The central cross section of each assembly was exposed, and three regions were visualized by scanning electron microscopy (SEM): taper interface, axial wall, and index region. The premachined base was used as the control. The groups were compared using analysis of variance (ANOVA) and Tukey post hoc test (α = .05). RESULTS: The results showed that acid bathing produced intermediary roughness between premachined and blasted surfaces (P < .05). SEM images showed a sealed interface at the taper region of all groups, despite some irregularities after alumina blasting. Increased discrepancies at the axial wall and index region were found after the alumina blasting procedure (P < .05). CONCLUSION: It was concluded that acid bathing should be used, instead of blasting to remove the oxide layer, to produce a better fit and smoother surface on UCLAs.

A Prospective Clinical Study of Alumina-Toughened Zirconia Abutments for Implant-Supported Fixed Restorations with a Mean Follow-up Period of 6.9 Years.

PURPOSE: The goal of this study was to compute the estimated cumulative survival and success rates of alumina-toughened zirconia (ATZ) abutments used for external connection-type implant-supported fixed dental prostheses (FDPs) after a mean follow-up of 6.9 years (82.3 months). MATERIALS AND METHODS: From May 1998 to July 2016, patients who provided informed consent and received implant-supported restorations with ATZ abutments were recruited. Clinical performance of zirconia abutments was evaluated using survival analysis. Failure was defined as the removal of the restoration due to zirconia abutment fracture, and complications included both failure and abutment screw problems. Survival and success were the counterparts of failure and complications, respectively. The effects of restoration-related factors (restored area, type of prosthesis, and implant system) on the survival and success of the abutments were estimated. RESULTS: A total of 231 patients were included in this study. One hundred twenty-six implant-supported single-unit and 204 multiple-unit FDPs were evaluated. All the placed implants had the external hex connection. The estimated cumulative 5-year, 7-year, and 10-year survival rates (95% confidence interval [CI]) of zirconia abutment-supported FDPs were 97.3% (95.5% to 99.1%), 96.8% (94.8% to 98.8%), and 94.1% (90.4% to 97.8%), respectively. The estimated cumulative 5-year, 7-year, and 10-year success rates (95% CI) were 94.1% (91.4% to 96.8%), 90.8% (87.3% to 94.3%), and 80.1% (73.6% to 86.6%), respectively. The type of prosthesis (P = .001) and implant system (P < .001) were the significant factors in the success of zirconia abutment-supported FDPs. CONCLUSION: Prefabricated ATZ abutments have a high predictability of survival at 10 years when used in implant-supported FDPs that replace both anterior and posterior teeth. However, the success of zirconia abutments was significantly influenced by the type of prosthesis and implant system.

Miniaturized Electromagnetic Device Abutment Improves Stability of the Dental Implants.

BACKGROUND: The overall success and predictability of dental implant treatment hinge on the primary stability, direct bone-to implant contact formation, and quantity and/or quality of residual bone. Pulsed electromagnetic field has been reported to increase bone regeneration in various clinical situations. Therefore, it was hypothesized that devices which could locally generate a Pulsed electromagnetic field would stimulate bone healing and increase bone density surrounding implants. OBJECTIVE: To retrospectively assess the effects of the miniaturized electromagnetic device (MED) on the implants stability for the first time in human subjects, in a prospective case controlled series. METHODS: Twelve consecutive patients (28 implants) were included in the study.Twelve MED healing caps and 16 regular control healing caps were inserted. Resonance frequency analysis (RFA) was performed at implant placement and abutment connection and an implant stability quotient value was given for each implant. RESULTS: Twenty-eight dental implants were included in the current study. Maxillary implants stability was significantly higher with MED healing cups compared with controls at 15 days postimplantation (66.2 vs 62.1, P = .0008). Resonance frequency analysis test performed at 30 days postimplantation demonstrated significantly increased stability in MED as compared with the control 73.5 ±â€Š3.2 vs 66.7 ±â€Š4.8 in mandibular implants and 74 ±â€Š1.7 vs 65 ±â€Š2.3 in maxillary implants. At the 50 days postimplantation, RFA tests revealed markedly higher stability of the maxillary implants with MED active healing caps compared with nonactive 75.4 ±â€Š5.1 vs 68.5 ±â€Š8.5, respectively. CONCLUSIONS: We conclude that MED-abutment implants demonstrated a superior stability during the early phase of healing as compared with standard implants.

Investigation of surface structure and biocompatibility of chitosan-coated zirconia and alumina dental abutments.

BACKGROUND: For long-term success of dental implants, it is essential to maintain the health of the surrounding soft tissue barrier, which protects the bone-implant interface from the microorganisms. Although implants based on titanium and its alloys still dominate the dental implant market, alumina (Al2 O3 ) and zirconia (ZrO2 ) implant systems are widely used in the area. However, they provide smooth and bioinert surfaces in the transmucosal region, which poorly integrate with the surrounding tissues. OBJECTIVE: The main aim of this research was to investigate the surface characteristics and biocompatibility of chitosan-coated alumina and zirconia surfaces. MATERIALS AND METHODS: The substrates were coated via solution casting technique. Additionally, an aging process with a thermocycle apparatus was applied on the coated materials to mimic the oral environment. To define the morphology and chemical composition of the surfaces of untreated, chitosan-coated, and chitosan-coated-aged samples, scanning electron microscopy and energy dispersive X-ray spectrometry were used. The phases and bonds characterized by Fourier transform infrared spectroscopy and X-ray diffraction analysis. The human gingival fibroblast cells were used to evaluate cytocompatibility by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium salt assay. RESULTS: It was observed that both substrates were successfully coated with chitosan and the aging process did not significantly affect the integrity of the coating. The attachment and proliferation of human gingival fibroblast cells were shown to be good on both kinds of chitosan-coated surfaces. CONCLUSION: Coating zirconia and alumina surfaces with chitosan is an efficient surface modification for increasing biocompatibility and bioactivity of these materials in vitro.

Fifteen-year survival of anterior all-ceramic cantilever resin-bonded fixed dental prostheses.

PURPOSE: The aim of this follow-up study was to report the long-term outcome of all-ceramic cantilever resin-bonded fixed dental prostheses (RBFDPs). MATERIALS AND METHODS: In 16 patients (mean age of 33.3±17.5years) 22 RBFDPs made from a glass-infiltrated alumina ceramic (In-Ceram) were inserted with a phosphate monomer containing luting agent after air-abrasion of the retainer wings. The abutment preparation included a shallow groove on the cingulum and a small proximal box. The restorations replacing 16 maxillary and 6 mandibular incisors were followed over a mean observation time of 188.7 months. RESULTS: No restoration debonded. Two RBFDPs fractured and were lost 48 and 214 months after insertion, respectively. The 10-year and 15-year survival rates were both 95.4% and dropped to 81.8% after 18 years. CONCLUSION: Anterior all-ceramic cantilever RBFDPs exhibited an excellent clinical longevity.

Aluminum Oxide Sandblasting of Hexagonal Coping and Abutment: Influence on Retention and Marginal Leakage Using Temporary Cements.

PURPOSE: To compare the tensile strength and marginal leakage of prefabricated abutments/copings, with or without surface sandblasting with aluminum oxide, luted with a calcium hydroxide-based temporary cement (CH, Dycal; Dentsply, Petrópolis, RJ, Brazil) or a noneugenol zinc oxide cement (ZO, Temp Bond NE; Kerr, Orange, CA). MATERIALS AND METHODS: A total of 48 CeraOne abutment analogs and respective copings were divided into 6 groups (n = 8) according to the component that was sandblasted: the coping only, coping + abutment or no sandblasting and the temporary cement used: CH or ZO. After cementation, the samples underwent 500 thermal cycles (5°C ± 2°C and 55°C ± 2°C) and were subsequently immersed in an aqueous solution of 0.5% basic fuchsine dye for 24 hours. Next, the tensile test was performed, and microleakage was assessed qualitatively. Data were analyzed using Mann-Whitney, Kruskal-Wallis tests, followed by the Student-Newman-Keuls test (α = 0.05). RESULTS: CH cement showed a tensile strength (245.6 N) significantly higher than that of the ZO (18.1 N). Sandblasting both abutment and coping increased tensile strength by 1.7 times. Marginal leakage was not influenced by sandblasting; however, CH presented less microleakage. CONCLUSION: Aluminum oxide sandblasting of the coping and abutment favored the tensile strength of temporary cements and the CH showed a higher tensile strength and less microleakage than did the ZO cement.

Long-term clinical, technical, and esthetic outcomes of all-ceramic vs. titanium abutments on implant supporting single-tooth reconstructions after at least 5 years.

AIM: The aim of this prospective cohort study was to evaluate clinical, radiographic, technical, esthetic, and patient-centered outcomes of implants using two different restoration materials after 5-9 years. MATERIALS AND METHODS: The study included 28 patients (test group: 13 patients with all-ceramic crowns on aluminum oxide-based abutments; control group: 15 patients with metal abutments on porcelain-fused-to-metal crowns). Evaluation of patient satisfaction, clinical (periodontal probing depth, bleeding on probing, plaque index, mucosal recession, and width of keratinized mucosa), esthetical (papilla index, clinical crown length), technical (loss of retention, marginal adaptation, chipping of ceramic, anatomical shape, occlusal wear, color match), and radiological parameters were assessed. The statistical analyses included comparison of all-ceramic vs. metal abutments and between the groups using Mann-Whitney U-tests. For esthetic parameters, changes over time were assessed using Friedman test and post hoc Wilcoxon test of all complete cases. RESULTS: The survival rate of the restoration was 100% in both groups. Patient's satisfaction revealed 9.7 on the visual analog scale. A low satisfaction correlated with low ratings in color or anatomical shape. The mucosal recession in the test group was less than that in the control group. An increase in distal papilla height in the year 0 to 1, and a decrease from year 1 to 8, was detected. Sites, which received a soft tissue graft, revealed stable papillae over the observation period. Clinical crown length showed higher values in the control group. CONCLUSIONS: Within the limitations of the study, it can be concluded that all-ceramic restorations reveal a high survival rate of 100% and show no difference to metal after a mean observation period of 7.2 years.

Discrepancies in marginal and internal fits for different metal and alumina infrastructures cemented on implant abutments.

Cemented crowns are increasingly being used on dental implants instead of on screw-retained prostheses because of the reliability of internal Morse taper implant-abutment connections. However, there is a lack of information on the fit of metal ceramic and premachined alumina infrastructures. Therefore, the aim of this study was to evaluate the marginal and internal fits of different metal and alumina infrastructures cemented on universal post abutments. A total of 45 abutments (6 mm in height and 3.3 mm in diameter) were divided into five groups on the basis of their infrastructure material: cobalt-chromium (CoCr), nickel-chromium (NiCr), nickel-chromium-molybdenum-titanium (NiCrMoTi), gold (Au), and premachined alumina. The alumina group showed marginal overextension, and the Au group showed the highest discrepancy in marginal fit among the metal alloys. The CoCr and alumina groups showed the lowest discrepancies in internal fit. In conclusion, the alumina cylinders exhibited the best internal fit, despite their horizontal overextension. Among the metal alloys, CoCr exhibited the best fit at critical regions, such as the cervical and occlusal areas.

Alumina reinforced zirconia implants: effects of cyclic loading and abutment modification on fracture resistance.

OBJECTIVE: The aim of the study was to evaluate the thermomechanical behavior of alumina-toughened zirconia (ATZ) oral implants in the artificial mouth and the fracture resistance (fracture load and bending moment) in a subsequent static fracture load test. The effects of abutment modification and different cyclic loadings were evaluated. METHODS: A total of 48 implants were used. 24 implants were left as machined (Group A), and 24 implants were shape modified at the abutment (Group B). Groups were divided into three subgroups composed of 8 samples each (A1/B1: no cyclic loading; A2/B2: 1.2 million cycles; A3/B3: 5 million cycles). Subsequently, all implants were statically loaded to the point of fracture. RESULTS: The implants showed the following survival rates after the artificial mouth: A2 and B2 100%; A3 and B3 87.5%. The following average fracture resistance values were found (fracture load [N]/bending moment [Nmm]): A1 (583/2907), B1 (516/2825), A2 (618/2737), B2 (550/3150), A3 (802/3784) and B3 (722/3809). After 5 million loading cycles a significant increase in fracture load and bending moment was found. Modification of the abutment significantly decreased the fracture load of implants without foregoing dynamic loading. However, the shape modification altered the lever arm. For that reason, a smaller load resulted in the same bending moment. Therefore, abutment modification had no significant influence on the fracture resistance of ATZ. SIGNIFICANCE: Neither thermomechanical cycling in an aqueous environment nor modification of the abutment had a negative effect on the fracture resistance of ATZ.

A direct bonded fixed partial dental prosthesis: a clinical report.

A direct bonded fixed partial dental prosthesis, with a composite resin denture tooth as a pontic, a tri-n-butylborane initiated adhesive resin, and screw posts for reinforcement, was still functioning after an observation period of 20 years. The prosthesis was found to be reliable for long-term clinical use when chemically and mechanically reinforced.

Fracture Strength of Zirconia and Alumina Ceramic Crowns Supported by Implants.

Due to the brittleness and limited tensile strength of the veneering glass-ceramic materials, the methods that combine strong core material (as zirconia or alumina) are still under debate. The present study aims to evaluate the fracture strength and the mechanism of failure through fractographic analysis of single all-ceramic crowns supported by implants. Forty premolar cores were fabricated with CAD/CAM technology using alumina (n = 20) and zirconia (n = 20). The specimens were veneered with glass-ceramic, cemented on titanium abutments, and subjected to loading test until fracture. SEM fractographic analysis was also performed. The fracture load was 1165 (±509) N for alumina and 1638 (±662) N for zirconia with a statistically significant difference between the two groups (P = 0.026). Fractographic analysis of alumina-glass-ceramic crowns, showed the presence of catastrophic cracks through the entire thickness of the alumina core; for the zirconia-glass-ceramic crowns, the cracks involved mainly the thickness of the ceramic veneering layer. The sandblast procedure of the zirconia core influenced crack path deflection. Few samples (n = 3) showed limited microcracks of the zirconia core. Zirconia showed a significantly higher fracture strength value in implant-supported restorations, indicating the role played by the high resistant cores for premolar crowns.

Treatment planning and dental rehabilitation of periodontally compromised partially edentulous patient: a case report - part II.

When planning a prosthetic rehabilitation of a periodontally compromised case, the clinician is often confronted with difficulties and dilemmas related to selecting the appropriate treatment that would provide long-term successful outcomes in function and esthetics. In such cases, a correct diagnosis and prognosis of the intraoral situation supported by evidence-based dentistry is the basis for the establishment of a proper treatment strategy. In this second part of a two-part treatment planning series, a systematic approach of patient examination and prognosis of each tooth is presented. Furthermore, different removable and fixed treatment possibilities are described and the rationale governing the decision-making process is revealed. The execution of the final treatment plan as specified by the concept of comprehensive dental care is outlined, and the final outcome is discussed according to the literature.

The effect of surface modification on the retention strength of polyetheretherketone crowns adhesively bonded to dentin abutments.

STATEMENT OF PROBLEM: The mechanical properties of polyetheretherketone (PEEK) make it an ideal material for fixed dental prostheses; however, insufficient information is available about the cementation of these restorations. PURPOSE: The purpose of this study was to evaluate the retention strength of differently pretreated and conditioned PEEK crowns luted to dental abutments. MATERIAL AND METHODS: Human teeth were prepared in a standardized manner, and PEEK crowns were milled (N=160, n=10 per group) and conditioned as follows: airborne-particle abrasion, sulfuric etching, piranha etching, and no conditioning. These groups were divided into adhesive systems: visio.link, Signum PEEK Bond, Ambarino P60, and no adhesive and luted to dentin abutments. After water storage (60 days) and thermocycling (5000 cycles, 5°C/55°C), the retention strength of the crowns was determined with a pull-off test, and failure types were classified. The data were analyzed with the Kruskal-Wallis, 1-way ANOVA, and χ(2) test (α=.05). RESULTS: Crowns that were unconditioned and piranha etched and/or adhesively untreated or pretreated with Ambarino P60 had the lowest retention strength. The highest values were found for the airborne-particle abrasion and sulfuric etched groups and/or crowns adhesively pretreated with Signum PEEK Bond and visio.link. Composite resin cement that remained on dentin was observed more frequently for unconditioned groups in combination with Ambarino P60 and no adhesive pretreatment. Mixed failure types were found more frequently in the airborne-particle abrasion group in combination with visio.link, Signum PEEK Bond, and no adhesive pretreatment, in the sulfuric acid etched group combined with Ambarino P60 and no adhesive pretreatment, and after the piranha acid pretreatment in combination with visio.link or Signum PEEK Bond. CONCLUSIONS: The adhesion of the tested PEEK crowns to dentin was satisfactory after treatment with airborne-particle abrasion or etching with sulfuric acid and/or when additional adhesive systems such as visio.link or Signum PEEK Bond were used.

A comparative study on microgap of premade abutments and abutments cast in base metal alloys.

The study compared the marginal accuracy of premade and cast abutments. Premade titanium, stainless steel, and gold abutments formed the control groups. Plastic abutments were cast in nickel-chromium, cobalt-chromium and grade IV titanium. The abutment/implant interface was analyzed. Analysis of variance and Duncan's multiple range test revealed no significant difference in mean marginal microgap between premade gold and titanium abutments and between premade stainless steel and cast titanium abutments. Statistically significant differences (P < .001) were found among all other groups.

Inlay-retained cantilever fixed dental prostheses to substitute a single premolar: impact of zirconia framework design after dynamic loading.

The purpose of this in-vitro study was to evaluate the influence of the framework design on the durability of inlay-retained cantilever fixed dental prostheses (IR-FDPs), made from zirconia ceramic, after artificial ageing. Forty-eight caries-free human premolars were prepared as abutments for all-ceramic cantilevered IR-FDPs using six framework designs: occlusal-distal (OD) inlay, OD inlay with an oral retainer wing, OD inlay with two retainer wings, mesial-occlusal-distal (MOD) inlay, MOD inlay with an oral retainer ring, and veneer partial coping with a distal box (VB). Zirconia IR-FDPs were fabricated via computer-aided design/computer-aided manufacturing (CAD/CAM) technology. The bonding surfaces were air-abraded (50 µm alumina/0.1 MPa), and the frameworks were bonded with adhesive resin cement. Specimens were stored for 150 d in a 37°C water bath during which they were thermocycled between 5 and 55°C for 37,500 cycles; thereafter, they were exposed to 600,000 cycles of dynamic loading with a 5-kg load in a chewing simulator. All surviving specimens were loaded onto the pontic and tested until failure using a universal testing machine. The mean failure load of the groups ranged from 260.8 to 746.7 N. Statistical analysis showed that both MOD groups exhibited significantly higher failure loads compared with the other groups (i.e. the three OD groups and the VB group) and that there was no significant difference in the failure load among the OD groups and the VB group. In conclusion, zirconia IR-FDPs with a modified design exhibited promising failure modes.

Interdisciplinary treatment of a periodontally compromised adult patient with multiple missing posterior teeth.

This article reports the comprehensive, interdisciplinary treatment of a 50-year-old periodontally compromised adult patient with multiple missing posterior teeth. After initial periodontal treatment, the maxillary first molars and right central incisor were intruded orthodontically. Miniscrews were used to intrude the maxillary first molars by 3 mm. The mandibular arch was restored with a tooth-supported overdenture. Root coverage of the maxillary right central incisor was performed using Alloderm (Biohorizons, Birmingham, Ala). At the end of the interdisciplinary therapy, the results were esthetically pleasing, with the patient's oral functions restored to the optimum. The emphasis of this report is to highlight the importance of integrating various specialties such as periodontics, orthodontics, endodontics, and restorative dentistry toward a common goal of improving the patient's oral health, function, and esthetics.

Effect of surface treatment on the retention of implant-supported zirconia restorations over short abutments.

STATEMENT OF PROBLEM: The retention of cement-retained implant-supported restorations can be affected by the height of the abutments. PURPOSE: The purpose of this study was to evaluate the effects of the surface treatment on the retention of implant-supported zirconia restorations over short abutments. MATERIAL AND METHODS: Eighty solid abutments reduced to 3 mm in height and their corresponding fixture replicas were embedded vertically in autopolymerizing acrylic resin blocks. Eighty zirconia copings (Cercon) with an occlusal loop were fabricated and divided into 2 groups (n=40). One group was airborne-particle abraded with 110 µm aluminium oxide and the other group was treated with silica coating (Rocatec System). Each group was then divided into 4 subgroups (n=10). The subgroups received either no treatment (control) or were treated with silane (Clearfil Porcelain Bond Activator+SE Primer), acid etching followed by silane, or ceramic primer (Clearfil). All copings were luted with a self-adhesive luting agent (Clearfil SA). After 1 week of conditioning in artificial saliva and thermal cycling (5000 cycles, 5°C-55°C), the removal force of the copings were tested with a universal testing machine at a 5 mm/min crosshead speed. The dislodgment force and failure mode were recorded. Two-way ANOVA and the Tukey honestly significant difference and the Fisher exact tests were used for data analysis (α=.05). RESULTS: The highest retentive values were obtained for airborne-particle abrasion--ceramic primer (228.84 N) and silica coating--ceramic primer (230.37 N), which were not significantly different from silica coating alone (216.26 N; P=.95) or a combination of airborne-particle abrasion followed by silanation (211.67 N; P=.87). The failure mode was primarily adhesive and cement principally remained on the copings. CONCLUSIONS: Within the limitations of this study, ceramic primer that contains adhesive phosphate monomer significantly improved the retention of zirconia ceramic restorations. Silicoating as a mechanical treatment provided greater retention for zirconia copings than airborne-particle abrasion when a resin-luting agent was used.

The fatigue bond strength of fixed-fixed versus cantilever resin-bonded partial fixed dental prostheses.

STATEMENT OF PROBLEM: Restorations using posterior resin-bonded partial fixed dental prostheses to replace missing premolar teeth were previously considered to have only variable success. Although 2-unit cantilevered resin-bonded partial fixed dental prostheses have been shown to have similar or improved clinical retention to their 3-unit counterparts, no in vitro evidence supports their use in preference to fixed-fixed designs. PURPOSE: The purpose of this in vitro study was to fatigue load 2 different resin-bonded partial fixed dental prosthesis designs (3-unit fixed-fixed and 2-unit cantilevered) and then compare their bond strengths after loading to failure. MATERIAL AND METHODS: Nickel chromium castings with cantilevered (n=10) and fixed-fixed framework designs (n=10) were bonded with a resin cement to stainless-steel tooth dies supported by a simulated periodontal ligament and subjected to cyclic loading (12 000 cycles). The abutment tooth analog was then secured in a universal testing machine, and the framework was loaded axially away from the tooth die until failure. Differences between the bond strengths of the 2 prosthesis designs were analyzed by a Mann-Whitney U test (P<.05). RESULTS: The bond strengths of the fixed-fixed group (332 N) were lowered by fatigue loading but not the cantilevered group (421 N) (P<.05). CONCLUSIONS: Three-unit fixed-fixed resin-bonded partial fixed dental prostheses were found to have a lower bond strength than 2-unit cantilevered resin-bonded partial fixed dental prostheses when fatigue loaded.

Clinical and radiographic evaluation of single-tooth dental implants placed in grafted extraction sites: a one-year report.

OBJECTIVE: The aim of this report was to clinically and radiographically evaluate changes to the hard and soft tissues around implants placed in extraction sockets grafted with medical grade calcium sulfate hemihydrate (MGCSH) mixed with platelet-rich plasma (PRP) and a collagen resorbable plug after one year of function. METHODS: This evaluation was part of a previous study conducted to evaluate extraction socket grafts. Fourteen subjects out of 16 were evaluated. After tooth extraction, eight subjects received MGCSH mixed with PRP in the extraction sockets (test group), and six subjects received collagen resorbable plug dressing material (control group). After three months of bone healing, dental implants were placed. Three months after implant installation, provisional restorations were placed and implants were loaded in function for one month followed by definitive restorations. Follow-up examinations and intraoral digital radiographs were made at baseline and one year after definitive restorations to evaluate the marginal bone level in each subject. RESULTS: At the one-year follow-up, the survival and success rate was 100% for all implants. There was no statistically significant difference in the amount of vertical bone loss between groups after 1 year (p > 0.05). For the test group, there was a mean mesial bone loss of -0.8 +/- 0.6mm and a mean distal bone loss of -0.5 +/- 0.4mm. For the control group, there was a mean mesial bone loss of -1.1 +/- 0.7mm and a mean distal bone loss of -0.6 +/- 0.6mm. CONCLUSIONS: At the one-year follow-up, the implant placement in grafted sockets was not affected by the type of the graft material. Implants placed in sockets grafted with MGCSH mixed with PRP showed less marginal bone loss after one year in comparison to those with collagen resorbable grafts.

Evaluation of human peri-implant soft tissues around alumina-blasted/acid-etched standard and platform-switched abutments.

This study evaluated the histometric characteristics of the peri-implant mucosa of human subjects that received textured implant abutments with conventional (implant and abutment with same diameter) or platform-switched (implant diameter wider than that of the abutment) configurations. Wider and longer connective tissue around platform-switched implants was observed compared to that with conventional abutments. Despite the different dimensions between the two abutment types, the abutment-soft tissue interaction was similar for both groups at the histometric level.