Anja Zembic

Systematic review of the survival rate and the incidence of biological, technical, and aesthetic complications of single crowns on implants reported in longitudinal studies with a mean follow‐up of 5 years

OBJECTIVE To assess the 5-year survival of implant-supported single crowns (SCs) and to describe the incidence of biological, technical, and aesthetic complications. The focused question was: What is the survival rate of implants supporting single crowns and implant-supported crowns with a mean follow-up of 5 years and to which extent do biological, technical, and aesthetic complications occur? METHODS A Medline search (2006-2011) was performed for clinical studies focusing on implant-supported SCs with a mean follow-up of at least 5 years. The search was complemented by an additional hand search and the inclusion of 24 studies from a previous systematic review (Jung et al. 2008a). Survival and complication rates were analyzed using random-effects Poissons regression models to obtain summary estimates of 5- and 10-year proportions. RESULTS Forty-six studies derived from an initial search count of 1083 titles and the complementary publications from the previous systematic review (Jung et al. 2008a) were selected and the data were extracted. Based on the meta-analysis, survival of implants supporting SCs at 5 years amounted to 97.2% (95% CI: 96.3-97.9%), and at 10 years amounted to 95.2% (95% CI: 91.8-97.2%). The survival of implant-supported SCs was 96.3% (95% CI: 94.2-97.6%) after 5 years and 89.4% (95% CI: 82.8-93.6%) after 10 years. For biological complications, a 5-year cumulative soft tissue complication rate of 7.1% (95% CI: 4.4-11.3%) and a cumulative complication rate for implants with bone loss >2 mm of 5.2% (95% CI: 3.1-8.6%) were calculated. Technical complications reached a cumulative incidence of 8.8% (95% CI: 5.1-15.0%) for screw-loosening, 4.1% (95% CI: 2.2-7.5%) for loss of retention, and 3.5% (95% CI: 2.4-5.2%) for fracture of the veneering material after 5 years. The cumulative 5-year aesthetic complication rate amounted to 7.1% (95% CI: 3.6-13.6%). CONCLUSIONS The outcomes of the meta-analysis demonstrated high implant survival rates for both the single tooth implants and the respective single crowns after 5 and 10 years. However, technical, biological, and aesthetic complications were frequent.

A systematic review of the survival and complication rates of implant‐supported fixed dental prostheses (FDPs) after a mean observation period of at least 5 years

OBJECTIVES The objective of this systematic review was to assess the 5- and 10-year survival of implant-supported fixed dental prostheses (FDPs) and to describe the incidence of biological and technical complications. METHODS An electronic Medline search complemented by manual searching was conducted to identify prospective and retrospective cohort studies and case series on FDPs with a mean follow-up time of at least 5 years. Patients had to have been examined clinically at the follow-up visit. Failure and complication rates were analyzed using standard and random-effects Poisson regression models to obtain summary estimates of 5-year and 10-year survival and complication rates. RESULTS The updated search provided 979 titles and 257 abstracts. Full-text analysis was performed for 90 articles resulting in a total 32 studies that met the inclusion criteria. Meta-analysis of these studies indicated an estimated survival of implants supporting FDPs of 95.6% after 5 years and 93.1% after 10 years. When machined surface implants were excluded from the analysis and only rough surface implants included, the survival rate increased to 97.2% after 5 years. The survival rate of implant-supported FDPs was 95.4% after 5 years and 80.1% after 10 years of function. When the analysis was done exclusively for metal-ceramic FDPs, hence the old gold-acrylic FDPs were excluded, the survival rate increased significantly. The survival rate of metal-ceramic implant-supported FDPs was 96.4% after 5 years and 93.9% after 10 years. Only 66.4% of the patients were free of any complications after 5 years. The most frequent complications over the 5-year observation period were fractures of the veneering material (13.5%), peri-implantitis and soft tissue complications (8.5%), loss of access hole restoration (5.4%), abutment or screw loosening (5.3%), and loss of retention of cemented FDPs (4.7%). CONCLUSION It may be concluded that implant-supported fixed dental prostheses (FDPs) are a safe and predictable treatment method with high survival rates. However, biological and technical complications were frequent (33.6%). To minimize the incidence of complications, dental professionals should make great effort in choosing reliable components and materials for implant-supported FDPs and the patients should be placed in well-structured maintenance system after treatment.

A systematic review of the performance of ceramic and metal implant abutments supporting fixed implant reconstructions

OBJECTIVES The objective of this systematic review was to assess the 5-year survival rates and incidences of complications associated with ceramic abutments and to compare them with those of metal abutments. METHODS An electronic Medline search complemented by manual searching was conducted to identify randomized-controlled clinical trials, and prospective and retrospective studies providing information on ceramic and metal abutments with a mean follow-up time of at least 3 years. Patients had to have been examined clinically at the follow-up visit. Assessment of the identified studies and data abstraction was performed independently by three reviewers. Failure rates were analyzed using standard and random-effects Poisson regression models to obtain summary estimates of 5-year survival proportions. RESULTS Twenty-nine clinical and 22 laboratory studies were selected from an initial yield of 7136 titles and data were extracted. The estimated 5-year survival rate of ceramic abutments was 99.1% [95% confidence interval (CI): 93.8-99.9%] and 97.4% (95% CI: 96-98.3%) for metal abutments. The estimated cumulative incidence of technical complications after 5 years was 6.9% (95% CI: 3.5-13.4%) for ceramic abutments and 15.9% (95% CI: 11.6-21.5%) for metal abutments. Abutment screw loosening was the most frequent technical problem, occurring at an estimated cumulative incidence after 5 years of 5.1% (95% CI: 3.3-7.7%). All-ceramic crowns supported by ceramic abutments exhibited similar annual fracture rates as metal-ceramic crowns supported by metal abutments. The cumulative incidence of biological complications after 5 years was estimated at 5.2% (95% CI: 0.4-52%) for ceramic and 7.7% (95% CI: 4.7-12.5%) for metal abutments. Esthetic complications tended to be more frequent at metal abutments. A meta-analysis of the laboratory data was impossible due to the non-standardized test methods of the studies included. CONCLUSION The 5-year survival rates estimated from annual failure rates appeared to be similar for ceramic and metal abutments. The information included in this review did not provide evidence for differences of the technical and biological outcomes of ceramic and metal abutments. However, the information for ceramic abutments was limited in the number of studies and abutments analyzed as well as the accrued follow-up time. Standardized methods for the analysis of abutment strength are needed.

Randomized‐controlled clinical trial of customized zirconia and titanium implant abutments for single‐tooth implants in canine and posterior regions: 3‐year results

OBJECTIVES The aim was to test whether or not zirconia abutments exhibit the same survival and technical/biological outcome as titanium abutments. MATERIAL AND METHODS Twenty-two patients receiving 40 single-tooth implants in canine and posterior regions were included. The implant sites were randomly assigned to 20 zirconia and 20 titanium abutments. All-ceramic and metal-ceramic crowns were fabricated. At baseline, 6, 12 and 36 months, the reconstructions were examined for technical and biological problems. Probing pocket depth (PPD), plaque control record (PCR) and bleeding on probing (BOP) were assessed at abutments (test) and analogous contralateral teeth (control). Standardized radiographs of the implants were made and the bone level (BL) was measured referring to the implant shoulder on mesial (mBL) and distal sides (dBL). The difference of color (DeltaE) of the peri-implant mucosa and the gingiva of control teeth was assessed with a spectrophotometer. The data were statistically analyzed with Mann-Whitney Rank and Students unpaired t-tests. RESULTS Eighteen patients with 18 zirconia and 10 titanium abutments were examined at a mean follow-up of 36 months (range 31.5-53.3 months). No fracture of an abutment or loss of a reconstruction was found. Hence, both exhibited 100% survival. At two metal-ceramic crowns supported by titanium abutments chipping of the veneering ceramic occurred. No difference of the biological outcome of zirconia and titanium abutments was observed: PPD (meanPPD(ZrO(2)) 3.2 +/- 1 mm, mPPD(Ti) 3.4 +/- 0.5 mm), PCR (mPCR(ZrO(2)) 0.1 +/- 0.2, mPCR(Ti) 0.1 +/- 0.2) and BOP (mBOP(ZrO(2)) 0.4 +/- 0.4, mBOP(Ti) 0.2 +/- 0.3). Furthermore, the BL was similar at implants supporting zirconia and titanium abutments (mBL(ZrO(2)) 1.7 +/- 1, dBL(ZrO(2)) 1.6 +/- 1; mBL(Ti) 2 +/- 1, dBL(Ti) 2.1 +/- 1). Both, zirconia and titanium abutments induced a similar amount of discoloration of the mucosa compared with the gingiva at natural teeth (DeltaE(ZrO(2)) 9.3 +/- 3.8, DeltaE(Ti) 6.8 +/- 3.8). CONCLUSIONS At 3 years, zirconia and titanium abutments exhibited same survival and technical, biological and esthetical outcomes.

Five-year results of implants with an oxidized surface placed predominantly in soft quality bone and subjected to immediate occlusal loading

STATEMENT OF PROBLEM Numerous studies have demonstrated the feasibility and predictability of immediate implant loading or immediate implant restoration. However, most of these studies report primarily short-term outcomes. PURPOSE The purpose of this prospective clinical study was to document the 5-year outcome of immediate occlusally loaded implants with an oxidized, microtextured surface placed to support fixed prostheses in various regions of the jaws. MATERIAL AND METHODS Thirty-eight patients received a total of 51 implant-supported fixed prostheses, 29 mandibular and 22 maxillary, the day of implant insertion. Thirty were fixed partial dentures (FPDs), 20 replaced single teeth, and 1 was a fixed mandibular complete denture. The restorations were supported by 102 slightly tapered, screw-type implants, the majority of which were placed in posterior regions (88%) and primarily in soft bone quality (76%). Patients with ongoing signs of parafunctional habits were not included. All implants were placed using conventional flap procedures. Treatment with local regenerative procedures in connection with implant placement was accepted within the study design. Resonance frequency implant stability measurements and marginal periimplant soft tissue evaluations were conducted. Radiographic examinations were performed at the time of prosthesis insertion, at 1-and 6-month follow-ups, and annually at the 1- through 5-year follow-up visits. This report presents the results after 5 years of loading, summarized with descriptive statistics. RESULTS Three maxillary implants were removed, although stable, in 1 patient at the 8-week follow-up due to postoperative infection in the adjacent guided bone regeneration (GBR) area. No additional implants were lost. This resulted in a cumulative implant success rate of 97.1% after 5 years of prosthetic loading. The mean marginal bone remodeling (SD) after 5 years of function was 1.54 (0.99) mm. At the 5-year examination, absence of marginal plaque and absence of bleeding on probing was reported for 75% and 74% of the sites, respectively, and remained generally unchanged from the 1-month follow-up. CONCLUSIONS The 5-year follow-up data indicate that an immediate loading protocol using a slightly tapered implant design with an oxidized, microtextured surface is a successful treatment alternative in regions exhibiting soft bone quality.

Systematic review of the survival rate and incidence of biologic, technical, and esthetic complications of single implant abutments supporting fixed prostheses.

PURPOSE To assess the 5-year survival rate and number of technical, biologic, and esthetic complications involving implant abutments. MATERIALS AND METHODS Electronic (Medline) and hand searches were performed to assess studies on metal and ceramic implant abutments. Relevant data from a previous review were included. Two reviewers independently extracted the data. Failure and complication rates were analyzed, and estimates of 5-year survival proportions were calculated from the relationship between event rate and survival function. Multivariable robust Poisson regression was used to compare abutment characteristics. RESULTS The search yielded 1,558 titles and 274 abstracts. Twenty-four studies were selected for data analysis. The survival rate for ceramic abutments was 97.5% (95% confidence interval [CI]): 89.6% to 99.4%) and 97.6% (95% CI: 96.2% to 98.5%) for metal abutments. The overall 5-year rate for technical complications was 11.8% (95% CI: 8.5% to 16.3%), 8.9% (95% CI: 4.3% to 17.7%) for ceramic and 12.0% (95% CI: 8.5% to 16.8%) for metal abutments. Biologic complications occurred with an overall rate of 6.4% (95% CI: 3.3% to 12.0%), 10.4% (95% CI: 1.9% to 46.7%) for ceramic, and 6.1% (95% CI: 3.1% to 12.0%) for metal abutments. CONCLUSIONS The present meta-analysis on single-implant prostheses presents high survival rates of single implants, abutments, and prostheses after 5 years of function. No differences were found for the survival and failure rates of ceramic and metal abutments. No significant differences were found for technical, biologic, and esthetic complications of internally and externally connected abutments.

Performance of Zirconia for Dental Healthcare

The positive results of the performance of zirconia for orthopedics devices have led the dental community to explore possible esthetical and mechanical outcomes using this material. However, questions regarding long-term results have opened strong and controversial discussions regarding the utilization of zirconia as a substitute for alloys for restorations and implants. This narrative review presents the current knowledge on zirconia utilized for dental restorations, oral implant components, and zirconia oral implants, and also addresses laboratory tests and developments, clinical performance, and possible future trends of this material for dental healthcare.

Immediate vs. early loading of dental implants: 3-year results of a randomized controlled clinical trial

OBJECTIVES The aim of the present study was to test whether or not immediately loaded implants exhibit the same survival rates as early loaded implants. MATERIAL AND METHODS Eleven patients with bilateral free end mandibles were randomly assigned to treatment either with immediately (test) or early loaded implants (control). Test implants received provisionals in occlusion on the day of surgery, control implants 6 weeks later. Parameters assessed included implant stability quotient (ISQ), plaque, prosthesis stability and radiographs at baseline (implant insertion), 1 and 3 years. The statistical analysis was performed by means of Students paired t-test and Wilcoxons signed-rank test. The level of significance was set at P<0.05. RESULTS After a mean observation period of 39.8 months (36.7-53.1), three test implants were lost in two patients resulting in a survival rate of 85% compared with 100% for control implants. At baseline, the mean marginal bone level was significantly higher at test implants (mean=0.36 mm, SD +/-0.5) compared with control implants (1.08+/-0.37 mm). For both test and control implants, the bone level significantly decreased from baseline to 3 years (test: 1.51+/-0.79 mm; control: 0.89+/-0.94 mm). The bone loss until 3 years was not significantly different between test and control group. There was no significant difference for ISQ both at test and control implants between baseline (test: 63.59+/-4.62 mm, control: 65.35+/-7.43 mm) and 3 years (test: 66.47+/-7.47 mm, control 68.80+/-8.75 mm). CONCLUSIONS Immediate loading was associated with a lower implant survival rate. Although the test implants were placed with increased sink depth compared with the control implants, the marginal bone levels were not different between test and control at 3 years.

Eleven‐Year Follow‐Up of a Prospective Study of Zirconia Implant Abutments Supporting Single All‐Ceramic Crowns in Anterior and Premolar Regions

BACKGROUND Clinical studies on zirconia abutments report very good survival rates and biological and technical results, but few have an observation period of more than 5 years. PURPOSE The aim of this study was to assess the long-term performance of customized zirconia implant abutments supporting all-ceramic crowns. MATERIALS AND METHODS Twenty-seven patients receiving 54 single implants were included (25 incisors, 14 canines, 15 premolars in both jaws). Yttria-stabilized zirconia abutments were screwed to the implants with a defined torque. All-ceramic crowns were adhesively cemented onto the abutments. The implants, abutments, and crowns were clinically and radiographically examined after 11 years of use. Modified United States Public Health Service (USPHS) criteria were used to assess technical outcomes: fracture of abutment/crown framework/veneering ceramic, loosening of abutment screw/crown, marginal adaptation, anatomical form, occlusal wear, and abutment fit. The biological parameters were pocket probing depth, plaque control record, bleeding on probing, papilla index, and gingival/mucosal recession at implants and neighboring natural teeth. The cumulative success rate of abutments and crowns was calculated by the Kaplan-Meier method. The results of the USPHS criteria were analyzed descriptively. RESULTS Sixteen patients with 31 zirconia abutments were examined at 11.3 (±0.9) years after implantation. No abutment or crown was lost. The cumulative success rate was 96.3% for abutments and 90.7% for crowns. Two abutment screws loosened, and three crowns exhibited minor chipping. There were no biological complications. CONCLUSIONS Customized zirconia single implant abutments exhibited excellent long-term outcomes in anterior and premolar regions.Background Clinical studies on zirconia abutments report very good survival rates and biological and technical results, but few have an observation period of more than 5 years. Purpose The aim of this study was to assess the long-term performance of customized zirconia implant abutments supporting all-ceramic crowns. Materials and Methods Twenty-seven patients receiving 54 single implants were included (25 incisors, 14 canines, 15 premolars in both jaws). Yttria-stabilized zirconia abutments were screwed to the implants with a defined torque. All-ceramic crowns were adhesively cemented onto the abutments. The implants, abutments, and crowns were clinically and radiographically examined after 11 years of use. Modified United States Public Health Service (USPHS) criteria were used to assess technical outcomes: fracture of abutment/crown framework/veneering ceramic, loosening of abutment screw/crown, marginal adaptation, anatomical form, occlusal wear, and abutment fit. The biological parameters were pocket probing depth, plaque control record, bleeding on probing, papilla index, and gingival/mucosal recession at implants and neighboring natural teeth. The cumulative success rate of abutments and crowns was calculated by the Kaplan-Meier method. The results of the USPHS criteria were analyzed descriptively. Results Sixteen patients with 31 zirconia abutments were examined at 11.3 (±0.9) years after implantation. No abutment or crown was lost. The cumulative success rate was 96.3% for abutments and 90.7% for crowns. Two abutment screws loosened, and three crowns exhibited minor chipping. There were no biological complications. Conclusions Customized zirconia single implant abutments exhibited excellent long-term outcomes in anterior and premolar regions.

Immediately restored one‐piece single‐tooth implants with reduced diameter: one‐year results of a multi‐center study

OBJECTIVES The aim of the present multi-center study was to evaluate the treatment outcome of immediately restored one-piece single-tooth implants with a diameter of 3 mm after 1 year. MATERIAL AND METHODS A total of 57 one-piece implants (NobelDirect 3.0) were inserted in 47 patients (26 females, 21 males) with a mean age of 31 years (range: 17-76 years) at five different centers. The implants replaced maxillary lateral incisors and mandibular incisors. The implants were placed either in conjunction with tooth extraction or in healed sites, and all implants were immediately restored with a provisional resin crown. If needed, the abutment part of the implant was prepared before crown cementation. The permanent crown was placed after 1.9-14.5 months. Radiographs were taken at implant insertion as well as after 6 and 12 months to evaluate the peri-implant marginal bone level and bone loss. Moreover, plaque, bleeding on probing and complications were assessed. RESULTS A total of 44 patients (23 females, 21 males) with 54 implants were available for the 1-year follow-up. One implant was lost, thus the 1-year implant survival was 98%. A statistically significant mean marginal bone loss was observed between baseline and 6 months (1.1 mm, range: -0.7 to 4.4 mm; n=49) and between baseline and 12 months (1.6 mm, range: -0.8 to 4.6 mm; n=50). A total of 18% of the implants were characterized by a bone loss of more than 3 mm. No bleeding on probing was observed around 83% of the implants. Plaque was registered at 15% of the implants. The most common complications were related to the provisional crown, i.e. fracture (n=3) and loss of retention (n=3). CONCLUSIONS A high 1-year implant survival was observed in the present study. However, the excessive peri-implant marginal bone loss around several implants indicates that this implant should be used with caution until further studies have been conducted.