Immediate implant placement vs. early implant treatment in the esthetic area. A 1-year randomized clinical trial.

OBJECTIVES: To assess the impact of implant placement and temporization timing on esthetic outcomes of single maxillary anterior implants with intact bone walls and interproximal bone. MATERIALS AND METHODS: Test group patients received an immediate implant with immediate provisional restoration and socket preservation, while patients in the control group received an early implant placement with guided bone regeneration and delayed loading. Patients were followed for 1 year after final prosthetic and pink esthetic score (PES), mid-buccal mucosal level (MBML), crestal bone changes (CBC), and peri-implant soft tissue parameters, and patient chair time was recorded. RESULTS: Fifty patients received the intended treatment (25 test and 25 control). No implants failed. PES after 1 year was 12.8 ± 1.19 for the test group and 12.5 ± 1.36 for the control group (p = .362). MBML difference between baseline (after final crown delivery) and the 1-year follow-up was gain of 0.2 ± 1.02 mm for the test group (p = .047) and no change in the control group. CBC after 1 year were 0.1 mm ± 0.21 mm (mesial) and 0.2 mm ± 0.22 mm (distal) for the test group and 0.2 mm ± 0.25 mm (mesial) and 0.3 mm ± 0.19 mm (distal) for the control group, p = .540 (mesial) and p = .462 (distal). Test group required half the chair time (127 ± 13 min) when compared to the control group (259 ± 15 min, p < .001). CONCLUSIONS: Within the limits of this trial, both treatment protocols resulted in excellent esthetic outcomes with PES >12 after 1-year follow-up.

A novel fully tapered, self-cutting tissue-level implant: non-inferiority study in minipigs.

OBJECTIVES: To assess the osseointegration and crestal bone level maintenance of a novel fully tapered self-cutting tissue-level implant for immediate placement (test) compared to a clinically established tissue-level implant (control) in moderate bone quality. MATERIALS AND METHODS: Test and control implants were compared in 3 groups, i.e., small-, medium-, and large-diameter implants in an edentulous mandibular minipig model with moderate bone quality after 12 weeks of healing. Histometrically derived bone-to-implant contact (BIC) and first bone-to-implant contact (fBIC) were subjected to statistical non-inferiority testing. Maximum insertion torque values in artificial bone were assessed for comparison. RESULTS: BIC values for the tests and control implants for all 3 diameters were comparable and non-inferior: small diameter (61.30 ± 10.63% vs. 54.46 ± 18.31%) (p=0.99), medium diameter (60.91 ± 14.42 vs. 54.68 ± 9.16) (p=0.55), and large diameter (45.60 ± 14.67 vs. 52.52 ± 14.76) (p=0.31). fBIC values for test implants were higher and non-inferior compared to control implants in all three groups. Test implants further showed distinctly higher maximum insertion torque values compared to control implants. CONCLUSION: The investigated novel tissue-level implant is able to achieve high levels of primary and secondary implant stability under simultaneous preservation of crestal bone levels. This qualifies the studied implant as an attractive candidate for immediate placement in bone of limited quality. CLINICAL RELEVANCE: This pilot pre-clinical study investigated a novel tissue-level implant for immediate placement. With the aim of translating the studied prototype into clinical application pre-clinical models, procedures and controls have been chosen with the aim of reflecting its future clinical indication and use.

Photo-activated implants: a triple-blinded, split-mouth, randomized controlled clinical trial on the resistance to removal torque at various healing intervals.

OBJECTIVES: Hydrophilic implant surfaces promote faster osseointegration of dental implants with a higher bone-implant contact (BIC) rate. Animal and in vitro studies proved that ultraviolet (UV) irradiation of titanium implants regains hydrophilicity. Clinical impact is still unclear. The objective of this RCT was to assess the removal torque (RT) required to unfix a surface-treated implant (test group) versus the original surface implant (control group) performed at various points in time. The null hypothesis stated that test and control implants will show the same deliberation force at specific time points. MATERIAL AND METHODS: One hundred eighty partially edentulous patients were randomly assigned to six groups. In single-stage surgery, each patient received one test and one control implant. In total, 180 test and 180 control implants were placed epicrestally. Test implants received a surface treatment with UV irradiation prior to insertion, in order to reduce carbon and enhance hydrophilicity and thus wettability. Maximum RT values for test and control implants were recorded with a torque measuring device at implant placement (T1), after 1 (group 1), 2 (group 2), 3 (group 3), 4 (group 4), 6 (group 5) (T2), and 8 weeks (group 6) of healing. Subsequently, implants were returned to their original position for the continuation of the healing process. RESULTS: No implant was lost. Age, gender, smoking, implant position, and bone quality could be excluded as confounding factors because of the lack of statistical significance. At T2, RT values were higher for test implants compared with those for control implants, being statistically significant in groups 2, 3, 4, and 6 (p < 0.05). CONCLUSIONS: Our data support rejection of the null hypothesis. CLINICAL RELEVANCE: Photo-activation of the surface of titanium implants leads to higher resistance to RT forces compared with that of non-treated implants, indicating improved healing and implant stability especially in the early healing phase.

Influence of titanium base, lithium disilicate restoration and vertical soft tissue thickness on bone stability around triangular-shaped implants: A prospective clinical trial.

OBJECTIVE: To evaluate how vertical mucosal tissue thickness affects crestal bone stability around triangular-shaped bone-level implants, restored with low profile titanium bases and monolithic lithium disilicate restorations. MATERIAL AND METHODS: Fifty-five bone-level implants of 4.3 mm diameter were evaluated in 55 patients (22 males and 34 females, mean age 48.3 ± 3.4 years) in prospective cohort study. According to vertical mucosal thickness, patients were assigned into three groups: 1 (thin, 2 mm or less), 2 (medium, 2.5 mm) and 3 (thick, 3 mm and more). Implants were placed in posterior mandible and maxilla in one-stage approach and, after integration, were restored with single screw-retained monolithic lithium disilicate crowns, using low gingival profile titanium bases. Radiographic examination was performed after implant placement and after 1-year follow-up. Crestal bone loss was registered mesially and distally, and mean value was calculated. One-way ANOVA and Tukey's HSD tests were applied; significance was set to 0.05. RESULTS: Mean vertical tissue thickness in 1 group was 1.76 ± 0.26 mm, 2 group-2.5 mm and 3.91 ± 0.59 mm in group 3, with statistically significant difference between all groups (p < 0.001). After 1-year follow-up, implants in group 1 (thin) had 1.25 ± 0.8 mm bone loss. Implants in group 2 (medium) had 0.98 ± 0.06, while implants in group 3 (thick) lost 0.43 ± 0.37 mm of crestal bone. Tukey's HSD test showed that differences between 1/3 and 2/3 were statistically significant (p < 0.001 and p = 0.0014, respectively), while between 1 and 2 was not significant (p = 0.310). CONCLUSIONS: Significantly less bone loss occurs around triangular-shaped bone-level implants in thick mucosal tissues (≥3 mm), compared to medium or thin tissue biotype. Crestal bone loss did not differ between medium and thin tissues.

The influence of mucosal tissue thickening on crestal bone stability around bone-level implants. A prospective controlled clinical trial.

OBJECTIVE: To evaluate how bone-level implants maintain crestal bone stability after thickening of thin mucosal tissues with allogenic membrane. MATERIALS AND METHODS: Ninety-seven bone-level implants of 4.1 mm diameter (Institute Straumann AG, Switzerland) were evaluated in 97 patients (28 men and 69 women, mean age 47.3 ± 1.2 years). According to vertical gingival thickness, patients were assigned into test T1 (thin, 2 mm or less, n = 33), test T2 (thin thickened with allogenic membrane, n = 32) and control C groups (thick, more than 2 mm, n = 32). Implants were placed in posterior mandible in one-stage approach and after integration were restored with single screw-retained metal-ceramic restorations. Radiographic examination was performed after implant placement, 2 months after healing, after prosthetic restoration and after 1-year follow-up. Crestal bone loss was calculated mesially and distally. Mann-Whitney U-test was applied and significance was set to 0.05. RESULTS: After 2 months, implants in group T1 had 0.75 ± 0.11 mm bone loss mesially and 0.73 ± 0.10 mm distally. Implants in group T2 had 0.16 ± 0.06 mm mesially and 0.20 ± 0.06 mm distally. C group implants lost 0.17 ± 0.05 mm mesially and 0.18 ± 0.03 mm distally. Differences between T1/T2, and T1/C were statistically significant (P = 0.000) both mesially and distally, while between T2 and C was not significant mesially (P = 0.861) and distally (P = 0.827). After 1-year follow-up implants in group T1 had 1.22 ± 0.08 mm bone loss mesially and 1.14 ± 0.07 mm distally. Implants in group T2 had 0.24 ± 0.06 mm mesially and 0.19 ± 0.06 mm distally. C group implants lost 0.22 ± 0.06 mm mesially and 0.20 ± 0.06 mm distally. Differences between T1/T2, and T1/C were statistically significant (P = 0.000) both mesially and distally, while between T2 and C was not significant mesially (P = 0.909) and distally (P = 0.312). CONCLUSIONS: Significantly less bone loss can occur around bone-level implants placed in naturally thick mucosal tissues, in comparison with thin biotype. Augmentation of thin soft tissues with allogenic membrane during implant placement could be way to reduce crestal bone loss.

Radiological comparison of laser-microtextured and platform-switched implants in thin mucosal biotype.

OBJECTIVE: To compare how laser-microtextured implants and implants with platform switching maintain crestal bone stability in thin peri-implant tissues. MATERIAL AND METHODS: Thirty laser-microtextured implants of 4.6 mm diameter (Tapered Internal Laser-Lok, BioHorizons, Birmingham, AL, USA; Group 1) and 30 implants with platform switching of 5/4 mm diameter (Certain Prevail; Biomet/3i, Palm Beach Gardens, FL, USA; Group 2) were placed in 30 patients (12 males and 18 females, mean age 42.3 ± 2.4) with thin mucosal tissues (≤2 mm). Implants were placed in posterior mandible in one-stage approach and after integration were restored with screw-retained metal-ceramic restorations. Radiographic examination was performed after implant placement, 2 months after healing, at prosthetic restoration delivery and after 1-year follow-up. Mean crestal bone loss was calculated, Mann-Whitney U-test was applied, and significance was set to 0.05. RESULTS: After 2 months of healing, the crestal bone loss was 0.71 ± 0.25 mm SD (range, 0.25-1.6 mm) and 1.02 ± 0.25 mm SD (range, 0.6-1.55 mm) in groups 1 and 2, respectively (P = 0.001). At restorations' delivery, the crestal bone loss was 1.10 ± 0.30 mm SD (range, 0.65-1.85 mm) and 1.37 ± 0.27 mm SD (range, 0.90-1.80 mm) in groups 1 and 2, respectively (P = 0.001). After 1-year follow-up, the crestal bone loss was 1.41 ± 0.42 mm SD (range, +0.1-2.30 mm) and 1.43 ± 0.23 mm SD (range, 1-1.80 mm) in groups 1 and 2, respectively (P = 0.976). CONCLUSIONS: Laser-microtexturing of implant collar or platform-switched implant/abutment connection did not eliminate crestal bone loss, if at the time of implant placement vertical soft tissue thickness was ≤2 mm. However, laser-microtextured implants may present less proximal bone loss than platform-switching implants in the period before implant loading.

The use of acellular dermal matrix membrane for vertical soft tissue augmentation during submerged implant placement: a case series.

OBJECTIVE: To evaluate the efficiency of acellular dermal matrix membrane to augment vertical peri-implant soft tissue thickness during submerged implant placement. MATERIAL AND METHODS: Forty acellular dermal matrix-derived allogenic membranes (AlloDerm, BioHorizons, Birmingham, AL, USA) and 42 laser-modified surface internal hex implants (BioHorizons Tapered Laser Lok, Birmingham, AL, USA) were placed in submerged approach in 40 patients (15 males and 25 females, mean age 42.5 ± 1.7) with a thin vertical soft tissue thickness of 2 mm or less. After 3 months, healing abutments were connected to implants, and the augmented soft tissue thickness was measured with periodontal probe. The gain in vertical soft tissue volume was calculated. Mann-Whitney U-test was applied and significance was set to 0.05. RESULTS: All 40 allografts healed successfully. Thin soft tissue before augmentation had an average thickness of 1.54 ± 0.51 mm SD (range, 0.5-2.0 mm, median 1.75 mm), and after soft tissue augmentation with acellular dermal matrix, thickness increased to 3.75 ± 0.54 mm SD (range, 3.0-5.0 mm, median 4.0 mm) at 3 months after placement. This difference between medians was found to be statistically significant (P < 0.001). Mean increase in soft tissue thickness was 2.21 ± 0.85 mm SD (range, 1.0-4.5 mm, median 2.0 mm). CONCLUSIONS: It can be concluded that acellular dermal matrix membrane can be successfully used for vertical soft tissue augmentation.

Influence of mucosal tissue height on implant crestal bone: A 10-year follow-up of a controlled clinical trial.

OBJECTIVE: To evaluate the 10-year influence of soft tissue height (STH) on crestal bone level changes (CBC) in bone-level implants with non-matching internal conical connections. MATERIAL & METHODS: From the initial 97 patients, 59 (19 men, 40 women, age 55.86 ± 9.5 years) returned for the recall visit. Based on baseline STH, they were categorized into T1 (thin STH ≤2 mm, n = 33), T2 (thin STH augmented with allogenic tissue matrix (ATM), n = 32), and C (thick STH >2mm, n = 32). Implants were placed in the posterior mandible using a one-stage approach and received single screw-retained restorations. Clinical (PPD, BOP, PI) and radiographic examinations were conducted after 10 years, with CBC calculated mesial and distal to each implant. RESULTS: After 10 years, implants in surgically thickened (T2) or naturally thick STH (C) showed bone gains of 0.57 ± 0.55mm and 0.56 ± 0.40mm, respectively (p < 0.0001) shifting from an initial CBC of -0.21 ± 0.33 mm to 0.36 ± 0.29 mm in the thick STH group and -0.2 ± 0.35 mm to 0.37 ± 0.29 mm in the surgically thickened STH group after 10 years. Implants in naturally thin STH yielded a non-significant trend of bone loss (-0.12 ± 0.41mm; p > 0.05). CONCLUSIONS: Implants in thin STH (≤2 mm) exhibited greater CBC over the study period. Significant bone gains were observed in thick STH cases, indicating that naturally thick STH or STH augmentation with ATM and may contribute to maintaining CBC in long-term around implants. CLINICAL SIGNIFICANCE: This is the first long-term follow-up study suggesting that adequate soft tissue height around implants helps maintain stable peri-implant bone levels. While tissue thickness plays a key role, other factors also interact with peri-implant tissue height to sustain crestal bone stability over time.

Does residual cement around implant-supported restorations cause peri-implant disease? A retrospective case analysis.

OBJECTIVES: The purpose of this study was to determine the relationship between patients with a history of periodontitis and development of cement-related peri-implant disease. MATERIALS AND METHODS: Seventy-seven patients with 129 implants for this retrospective analysis were selected from completed implant cases that were scheduled for regular maintenance or had experienced mechanical or biological complications between years 2006 and 2011 in private practice. Implants with extracoronal residual cement and implants without cement remnants were analyzed. The selected cases were further divided into two groups--implants in patients with history of periodontitis (1) and implants in periodontitis-free individuals (2). The selection of these groups was made on the basis of treatment history and orthopantomograph. As a control group, a set of 238 screw-retained implant restorations, delivered to 66 patients during the same period of time was examined. The incidence of peri-implant disease among implants in all groups was calculated. RESULTS: Peri-implant disease was evident in 62 of 73 implants with cement remnants (85%). All implants in group 1 developed peri-implantitis--4 early and 35 delayed disease cases. In the periodontally healthy group, 20 of 31 implants were diagnosed with peri-implant mucositis, 3 implants had early peri-implantitis, and 11 implants with cement remnants did not develop biological complications. In the group of implants without cement remnants, peri-implant disease was diagnosed in 17 of 56 cases (30%). In contrast, only two occurrences of peri-implant disease were registered in the control group of screw-retained restorations (1.08%). CONCLUSIONS: Implants with cement remnants in patients with history of periodontitis may be more likely to develop peri-implantitis, compared with patients without history of periodontal infection.

The influence of the cementation margin position on the amount of undetected cement. A prospective clinical study.

OBJECTIVE: To evaluate the amount of undetected cement after cementation and cleaning of implant-supported restorations. MATERIALS AND METHODS: Fifty three patients were treated with 53 single implant-supported metal-ceramic restorations. The subgingival location of the margin of each implant was measured with a periodontal probe mesially, distally, buccaly, and lingually(,) resulting in 212 measurements. The data were divided into four groups: equally with tissue level (14 samples), 1 mm subgingivally (56), 2 mm (74), and 3 mm (68) below tissues contour. Metal-ceramic restorations were fabricated with occlusal openings and cemented on standard abutments with resin-reinforced glass-ionomer. After cleaning, a radiograph was taken to assess if all cement had been removed. Then the abutment/crown unit was unscrewed for evaluation. All quadrants of the specimens and peri-implant tissues were photographed and analyzed with Adobe Photoshop. Two proportions were calculated: (1) the relation between the cement remnants area and the total area of the abutment/restoration and (2) the relation between the cement remnants and the total area of implant soft tissue contour. Significance set to 0.05. RESULTS: Excess on the crown groups: 1 (0.002 ± 0.001); 2 (0.024 ± 0.005); 3 (0.036 ± 0.004); 4 (0.055 ± 0.007). Undetected excess increased when the margin was located deeper subgingivally (P = 0.000), significant difference was found among all groups (P ≤ 0.05). Remnants in the soft tissue groups: 1 (0.014 ± 0.006); 2 (0.052 ± 0.011); 3 (0.057 ± 0.009); 4 (0.071 ± 0.012). The increase of the remnants was statistically reliable (P = 0.0045), significant difference was found between group 1 and 2 (P ≤ 0.05). Radiographic evaluation showed that cement remnants mesially were visible in four cases of 53 or 7.5%, and in six cases of 53 distally (11.3%). CONCLUSIONS: The deeper the position of the margin, the greater amount of undetected cement was discovered. Dental radiographs should not be considered as a reliable method for cement excess evaluation.

A Novel Approach for Implant Rehabilitation Combined with Immediate Bone and Soft-Tissue Augmentation in a Compromised Socket-A B2S Approach: Case Report with a 2-Year Follow-Up.

In this case report, we aimed to describe a novel approach for aesthetic rehabilitation of the anterior maxilla that combined immediate implant installation with the "Bone2Soft Tissue Reconstruction" (B2S technique), which involves the use of a triple graft harvested from the maxillary tuberosity. The regeneration potential of a tuberosity graft appeared to surpass that of corticocancellous bone grafts harvested from other intraoral donor sites and allowed for quicker regeneration of both bone and soft tissue. The B2S technique extended the indications for immediate implant placement and ridge augmentation to cases involving severe bone resorption and other complex clinical scenarios. Owing to the good visualization facilitated by open-flap access, the surgical procedures can be completed in a single intervention, which will be beneficial for both doctors and patients.

Contour angle and peri-implant tissue height: Two interrelated features of the implant supracrestal complex.

OBJECTIVES: Recent research has suggested the contour of the prosthesis and the vertical height of the peri-implant mucosa as important parameters that can influence the long term health and stability of the peri-implant tissue. In particular, overcontouring of the prosthesis has been correlated with an increased risk for peri-implantitis, while reduced soft tissue height has been associated with marginal bone loss, recession, and other soft tissue complications. Although these two parameters have been investigated as independent in the current literature, clinical experience points toward a close interrelation between transmucosal tissue height and prosthesis contour angle. It is often found that a reduced vertical height of the implant supracrestal complex is the main reason for overcontouring of the prosthesis. At the same time, achieving a favorable contour of 30o or less is not possible unless the clinician has ensured an adequate vertical height of the soft tissue. The purpose of this short communication is to establish the relation between tissue vertical height and prosthesis contour by utilizing a theoretical geometry equation based on the Pythagorean theorem. In doing so, one can use the dimensions of the implant as well as those of the prosthesis at the mucosal margin to calculate the essential vertical height for achieving a favorable prosthesis contour. CONCLUSIONS: As the treatment plan of the implant supracrestal complex is "top-down," in case of deficient vertical height, subcrestal placement of the implant should be considered to achieve a proper prosthesis contour.

Influence of Cement Type on its Quality of Removal from Zirconium Oxide Implant-Supported Restorations

PURPOSE: To assess excess cement removal after cementation of implant-supported cementretained restorations using different cements. MATERIALS AND METHODS: A dental model with soft tissue imitation, 20 individual zirconium oxide abutments, and 20 zirconium oxide crowns were fabricated. Half of the restorations were cemented using resin cement (RX) and the other half with resin-modified glass-ionomer cement (GC). After cement cleaning, each crown-abutment unit was removed from the model, photographed, and analyzed from 4 surfaces, resulting in a final sample size of 80 measurements. Radiographic examination and the computerized planimetric method in Adobe Photoshop were used to determine the amount of the cement left and to evaluate the ratio between the area of cement residue and the whole crown-abutment surface. The significance was set to .05. RESULTS: GC resulted in 7.4% more cement residue on all surfaces (P < .05) than RX. The P value on three of the surfaces (all except mesial) was < .05, meaning that the data were statistically significantly different between groups and surfaces. Absolute removal of the cement was impossible in all cases (100%), and in 95% of the cases, cement remnants could not be detected radiographically. CONCLUSION: More undetected cement remains when using resin-modified glass-ionomer cement. It was impossible to remove excess of both types of cements completely. Most of the cement remains on the distal surface. Radiographic examination could not be considered as a reliable method to identify excess cement.

The influence of implant placement depth and impression material on the stability of an open tray impression coping.

STATEMENT OF PROBLEM: Subgingival positioning of a single dental implant may result in a less stable impression coping in a polymerized impression material. PURPOSE: The purpose of this study was to evaluate the influence of a single dental implant placement depth and different impression materials on the stability of an open tray impression coping. MATERIAL AND METHODS: Six polyvinyl chloride-based plastic models with single embedded internal hexagon implant analogs were fabricated. The implant analogs were placed equally with their surface 0, 1, 2, 3, 4, or 5 mm below the simulated gingival margin. Open tray impression copings were connected to the embedded implant analogs, and impressions were made with different vinyl polysiloxane (VPS) impression materials, polyethers, and an addition silicone-based occlusal registration material. The laboratory analogs were connected to the impression copings and the plastic trays were placed in a locking device. A measuring device, consisting of a compression force gauge connected to a platform moving at a speed of 3.2 mm/s, was fabricated. The impression trays were fixed so that the pole of the force gauge would touch the surface of the implant analog in the same place and push it 1.0 mm. Measurements of each specimen were made 5 times. Statistical analysis was performed with a 1-way ANOVA, the Tukey test, and the Pearson correlation coefficient (α=.05). RESULTS: There was a significant negative correlation between the dental implant placement depth and the force needed to move the impression coping (P<.05). In all depth groups, the impression coping was significantly more stable when the impressions were made with the occlusal registration material (P<.05). CONCLUSIONS: As the dental implant placement depth increased, the force needed to move the impression coping decreased. The coping was significantly more stable when an occlusal registration material was used to make the impression.

Connective tissue graft vs porcine collagen matrix after immediate implant placement in esthetic area: A randomized clinical trial.

BACKGROUND: The use of connective tissue graft (CTG) with immediate implant placement and provisionalisation have shown promising results. It is not clear if the same outcome could be achieved using porcine-derived collagen matrix (PDCM) as grafting material. OBJECTIVES: This study aimed to assess the esthetic and functional outcomes of immediate temporization of immediately placed fully tapered implants combined with bone and soft tissue augmentation, using either a CTG or a PDCM, in fresh extraction sockets of the anterior sites. MATERIALS AND METHODS: Patients with a failing anterior tooth were included in this study. After extraction, they received an immediate implant with simultaneous hard and soft tissue augmentation and immediate provisional restoration. Patients were randomly assigned to one of the group. Soft tissue augmentation in the control group (CTG) consisted of a CTG, whereas PDCM was used in the test group. After 4 months, definitive restorations were delivered, and pink esthetic score (PES) was evaluated at T1, prosthetic delivery, and at 12-month follow-up (T2). In addition, crestal bone change, probing depth, bleeding on probing, plaque index, bleeding on provisional removal, and implant stability quotient were also recorded. RESULTS: A total of 45 patients received the intended treatment (22 controls and 23 tests) 45 implants totally, with no implant failures at T2. PES mean ± SD after 1 year was noted to be 12.9 ± 1.2 for the CTG group and 12.1 ± 1.3 for the PDCM group (p = 0.507). CONCLUSION: Within the limits of this trial, both treatment protocols resulted in comparable esthetic outcomes, with results showing PES >12 and stable clinical parameters after 1 year of follow-up.

The influence of margin location on the amount of undetected cement excess after delivery of cement-retained implant restorations.

OBJECTIVES: The aim of this study was to evaluate the amount of the residual cement excess after cementation and cleaning of implant-supported restorations with various positions of the margins. MATERIAL AND METHODS: Twenty-five casts with embedded implant analogs and flexible soft-tissue imitation were used in the study. Individual abutments with different position of the margin - from 1 mm supragingivally to 3 mm below the gingival level - were modelled and divided equally into five groups. The same amount of polished metal crowns was luted to prosthetic abutments, excess cement was cleaned and the restorations were removed for evaluation of the undetected cement remnants. All quadrants of each specimen were photographed for calculation of the ratio between the cement remnants area and the total specimen area using Adobe Photoshop. Afterwards, cement remnants were cleared from each specimen and weighed with analytical balances. RESULTS: The measurements in all the groups consisted of (1) the relation between the cement remnants area and the total area of the specimen; and (2) cement excess weight in grams after cleaning: group 1 (0.0111 ± 0.021; 0.0003 ± 0.0001 g); group 2 (0.0165 ± 0.019; 0.0008 ± 0.0003 g); group 3 (0.0572 ± 0.028; 0.0013 ± 0.0005 g); group 4 (0.1158 ± 0.054; 0.0051 ± 0.0013 g); and group 5 (0.1171 ± 0.059; 0.0063 ± 0.0021 g). Results showed significant increase of undetected cement quantity, as the restoration margins were located deeper subgingivally, using weighting (P=0) and calculation of proportion (P=0). There was a significant correlation between evaluation techniques (r=0.889; P=0). CONCLUSIONS: The amount of residual cement after cleaning increased as the restoration margins were located more subgingivally.

Decompression technique - A modified approach for lateral alveolar ridge augmentation: A case report.

A particular technique can increase the mucosal and peri-implant bone thickness, prevent compression around implant neck, and obtain proper space for the following prosthetic treatment with an adequate emergence profile.

Influence of Implant Placement Depth and Soft Tissue Thickness on Crestal Bone Stability Around Implants With and Without Platform Switching: A Comparative Clinical Trial.

This case control study measured early crestal bone changes around subcrestally placed platform-switched implants surrounded by thin soft tissue and compared them with regular, matching-platform implants placed in a supracrestal position and surrounded by thick soft tissue. Sixty-six patients received two-piece internal hex dental implants. Control group patients (n = 33) received implants that had a horizontally matching implant-abutment connection and were placed approximately 0.5 to 1 mm supracrestally. Test group patients (n = 33) received platform-switched implants that were placed about 1.5 mm subcrestally. Clinical examinations were conducted, intraoral radiographs were taken, and statistical analysis was performed. After 2 months, the mean bone loss was 0.2 mm (SD: 0.22 mm; range: 0.1 to 1.2 mm) in the control group and -0.69 mm (SD: 0.65 mm; range: 0 to 2.6 mm) in the test group; this difference was found to be statistically significant (P < .05). After 1 year, mean bone loss was 0.28 mm (SD: 0.36 mm; range: 0.1 to 1.63 mm) in the control group and -0.6 mm (SD: 0.55 mm; range: 0.05 to 1.8 mm) in the test group. Platform-switched implants placed in a subcrestal position in vertically thin soft tissues showed statistically significantly more bone loss than non-platform-switched implants placed supracrestally with vertically thick tissues.

Full versus partial thickness flap to determine differentiation and over keratinization of non-keratinized mucosa. A 3-year split mouth randomized pilot study.

OBJECTIVES: It was shown, that Connective Tissue Grafts (CTG) retrieved from the tuberosity tends to determine hyperplastic responses and may induce a beneficial over-keratinization of non-keratinized mucosa. Clinically evaluate and compare CTG from tuberosity ability to increase soft tissue thickness and the keratinization potential after recipient area is either prepared using split or full thickness flap in edentulous mandible. MATERIALS AND METHODS: Fourty implants were placed in 10 edentulous patients with atrophied mandible (Class IV of Misch) presenting less than 1.0 mm of keratinized tissue using a flapless approach and immediately restored with acrylic temporary bridge on multi-unit abutments. The surgical sites were split-mouth randomized and prepared as CTG recipients by a tunneling procedure. Twenty benefited of a partial thickness approach and 20 of a full thickness one. The CTG was placed buccally using partial thickness or full thickness flap according to the randomization schedule. The width of keratinized tissue (KT), the horizontal soft tissue thickness (STT), the marginal hard and soft tissue levels as well as the implant success parameters were collected and analyzed. RESULTS: After a 3 year follow-up period the increase of KT was statistically significantly (p < 0.001) larger in the partial thickness group from 0.6(0.6) to 5.1(0.72) mm, while full thickness group showed very little improvement from 0.5(0.51) to 1(0.57) mm (p < 0.001). STT was significantly increased in both groups over time: from 2.4(0.88) to 5.4(0.68) mm in full thickness group and from 2.5(0.51) to 5.8(0.41) mm in partial thickness group without any significant difference between the groups. CONCLUSION: The increase of soft tissue thickness by using CTG from tuberosity was found in both groups, while keratinization of non-keratinized mucosa appeared more in the partial thickness group.

Crestal bone stability after flapless placement of sloped implants with immediate temporization in edentulous mandible. A prospective comparative clinical trial.

OBJECTIVES: The purpose of this study was to evaluate crestal bone stability around sloped implants using the flapless procedure and compare it with conventional implants placed axially. MATERIALS AND METHODS: A total of 40 bone-level implants with platform switching were used for this study for 10 patients (4 males and 6 females) in edentulous mandible. Twenty mesial conventional implants were placed in upright position and 20 distal 30° sloped implants tilted 30°. Bone loss was estimated using radiographic imaging after a 6- and a 12-month follow-up period. Comparison of the bone loss in the distal and mesial region at both implantation angles were conducted to understand the nature and progression of crestal bone loss. RESULTS: Crestal bone loss around the sloped implants was 0.29 mm (SD = 0.292) on average, while around conventional implants it was 0.22 mm (SD = 0.202) after one-year follow-up. However, there was no significant difference in the average of crestal bone loss between two trial groups after 6 months (p < 0.243) and one-year (p < 0.614) follow-up. The results indicated a 100% implant survival rate after one-year follow-up. Additionally, three fixed prostheses needed realignment after fracturing during the follow-up time. CONCLUSION: Considering the limitations of this study, it can be presumed that sloped and conventional implants with platform switching and conical connection have the same potential for minimal crestal bone loss.