A multicenter cohort study on the association of the one-abutment one-time concept with marginal bone loss around bone level implants.

OBJECTIVES: To investigate the association of the one-abutment one-time concept with marginal bone loss (MBL) around bone-level implants in relation to other factors. MATERIALS AND METHODS: Records from patients treated by four experienced implant surgeons between January 2016 and July 2019 were scrutinized. Subjects treated with two bone-level implant types with varying machined collar (subgroups: 0.5 and 0.8 mm) were considered, receiving a healing abutment (HA cohort) or a permanent abutment at the time of surgery (OT cohort). The primary outcome was MBL registered at 3 months and the longest follow-up. A clustered two-part regression model for semicontinuous data was used. RESULTS: Data pertaining to 160 patients (92 females, mean age 54) and 344 implants (125 in HA cohort, 219 in OT cohort) were available for evaluation. Mean MBL amounted to 0.52 mm (SD 0.68) after a mean follow-up of 20 (SD 9.2) months, with 33.8% of the implants showing complete bone preservation and 5.0% demonstrating >2mm MBL. OT was not related to the presence of MBL using MBL as dependent binary variable (0: no MBL; 1: MBL irrespective of its magnitude). However, OT significantly reduced the magnitude of MBL with 0.300mm when compared to HA (p = .023) in the cases where MBL was detected. Subgroup (p = .212), smoking (p = .789), history of periodontitis (p = .839), type of edentulism (p = .054), implant surgeon (p = .079), patient compliance (p = .617), and follow-up (p = .443) failed to show a significant association with MBL in the regression model. Ninety-eight % of the implants survived. CONCLUSION: Within the limitations of a cohort study, the one-abutment one-time concept was associated with a decrease in MBL at implant sites with bone loss. Therefore, the placement of a permanent abutment at the time of surgery seems relevant to limit marginal bone-level alterations.

The effectiveness of immediate implant placement for single tooth replacement compared to delayed implant placement: A systematic review and meta-analysis.

AIM: To compare immediate implant placement (IIP) to delayed single implant placement (DIP, ≥3 months post-extraction) in terms of implant survival (primary outcome), surgical, clinical, aesthetic, radiographic and patient-reported outcomes (secondary outcomes). MATERIALS AND METHODS: Two reviewers independently performed an electronic search in PubMed, Web of Science, EMBASE and Cochrane and a hand search to identify eligible studies up to May 2018. Only randomized controlled trials (RCTs) and non-randomized controlled studies (NRSs) comparing IIP to DIP with at least 1 year of follow-up were selected for a qualitative analysis and meta-analysis. RESULTS: The search identified 3 RCTs and 5 NRSs out of 2,589 titles providing data on 473 single implants (IIP: 233, DIP: 240) that had been in function between 12 and 96 months. One RCT showed unclear risk of bias, whereas all other studies demonstrated high risk. Meta-analysis showed significantly lower implant survival for IIP (94.9%) as compared to DIP (98.9%) (RR 0.96, 95% CI [0.93; 0.99], p = 0.02). All were early implant failures. A subgroup meta-analysis demonstrated a trend towards lower implant survival for IIP when postoperative antibiotics had not been administered (RR: 0.93, 95% CI [0.86; 1.00], p = 0.07). This was not observed among studies including the administration of postoperative antibiotics (RR: 0.98, 95% CI [0.94; 1.02], p = 0.35). Meta-analyses showed similar probing depth (WMD 0.43 mm, 95% CI [-0.47; 1.33], p = 0.35) and aesthetic outcomes as assessed by the pink aesthetic score (standardized WMD -0.03, 95% CI [-0.46; 0.39], p = 0.88) for IIP and DIP. Data on marginal bone loss were conflicting and highly biased. Soft tissue recession was underreported and available data were highly biased. Patient-reported outcomes were underreported, yet both IIP and DIP seemed well tolerated. CONCLUSION: Immediate implant placement demonstrated higher risk for early implant loss than DIP. There is a need for RCTs comparing IIP to DIP with CBCT analyses at different time points and data on midfacial recession with the preoperative status as baseline. In these studies, the need for hard and soft tissue grafting should also be evaluated.

How do peri-implant biologic parameters correspond with implant survival and peri-implantitis? A critical review.

OBJECTIVES: The aim of this critical review was to evaluate whether commonly used biologic diagnostic parameters correspond to implant survival and peri-implantitis prevalence. MATERIALS AND METHODS: Publications from 2011 to 2017 were selected by an electronic search using the Pubmed database of the US National Library of Medicine. Prospective and retrospective studies with a mean follow-up time of at least 5 years and reporting prevalence of peri-implantitis as well as mean bone loss and standard deviation were selected. The correlation between reported prevalence of peri-implantitis and reported implant survival, mean follow-up time, mean bone loss, mean probing depth, and mean bleeding on probing was calculated. Mean bone loss and standard deviation were used for estimation of proportion of implants with bone loss exceeding 1, 2, and 3 mm. RESULTS: Full-text analysis was performed for 255 papers from 4,173 available ones, and 41 met all the inclusion criteria. The overall mean weighted survival rate was 96.9% (89.9%-100%) and the reported prevalence of peri-implantitis ranged between 0% and 39.7%, based on 15 different case definitions. The overall weighted bone loss was 1.1 mm based on 8,182 implants and an average mean loading time ranging from 5 to 20 years. No correlation was found between mean bone loss and the reported prevalence of peri-implantitis. The estimated prevalence of implants with bone loss above 2 mm was 23%. The overall weighted mean probing depth was 3.3 mm, and mean weighted bleeding was 52.2%. Only a weak correlation was found between survival and function time (r = -0.49). There was no relation between the probing depth or bleeding and the mean bone loss, mean follow-up time, and reported prevalence of peri-implantitis. CONCLUSION: Biologic parameters mean probing depth and mean bleeding on probing do not correlate with mean bone loss and this irrespective of follow-up. Case definition for peri-implantitis varied significantly between studies indicating that an unambiguous definition based on a specified threshold for bone loss is not agreed upon in the literature.

Implant surface roughness and patient factors on long-term peri-implant bone loss.

Dental implant placement is a common treatment procedure in current dental practice. High implant survival rates as well as limited peri-implant bone loss has been achieved over the past decades due to continuous modifications of implant design and surface topography. Since the turn of the millennium, implant surface modifications have focused on stronger and faster bone healing. This has not only yielded higher implant survival rates but also allowed modifications in surgical as well as prosthetic treatment protocols such as immediate implant placement and immediate loading. Stable crestal bone levels have been considered a key factor in implant success because it is paramount for long-term survival, aesthetics as well as peri-implant health. Especially during the past decade, clinicians and researchers have paid much attention to peri-implant health and more specifically to the incidence of bone loss. This could furthermore increase the risk for peri-implantitis, the latter often diagnosed as ongoing bone loss and pocket formation beyond the normal biological range in the presence of purulence or bleeding on probing. Information on the effect of surface topography on bone loss or peri-implantitis, a disease process that is to be evaluated in the long-term, is also scarce. Therefore, the current narrative review discusses whether long-term peri-implant bone loss beyond physiological bone adaptation is affected by the surface roughness of dental implants. Based on comparative studies, evaluating implants with comparable design but different surface roughness, it can be concluded that average peri-implant bone loss around the moderately rough and minimally rough surfaces is less than around rough surfaces. However, due to the multifactorial cause for bone loss the clinical impact of surface roughness alone on bone loss and peri-implantitis risk seems rather limited and of minimal clinical importance. Furthermore, there is growing evidence that certain patient factors, such as a history of periodontal disease and smoking, lead to more peri-implant bone loss.

A Split-Mouth Study to Assess the Effect of Implant Surface Roughness on Implant Treatment Outcome After 5 Years.

The aim of current split-mouth study was to compare the implant treatment outcomes of hybrid-surface implants (minimally rough implant collar and moderately rough body) with moderately rough implants after 5 years in patients with a bar-supported mandibular overdenture. Fully edentulous patients were enrolled, and each patient received two implants: one moderately rough and one hybrid-surface implant. A total of 18 patients with 36 implants attended the 5-year recall, and the implant survival rate was 100%. The 5-year evaluation showed no significant difference in crestal bone loss or peri-implant health between the hybrid and moderately rough implants.

Four-implant-supported overdenture treatment in the maxilla. Part I: A randomized controlled split mouth trial assessing the effect of microthreads and abutment connection type on 4 years peri-implant health.

BACKGROUND: According to literature, peri-implant bone loss is minimized on implants with microthreaded neck design and internal type of abutment connection. However, most clinical studies may be biased due to confounding factors. PURPOSE: This nonblinded RCT assessed the effect of implant neck (microthreaded vs non-microthreaded) as well as the type of abutment connection (internal conical vs external flat-to-flat) on peri-implant bone stability and peri-implant health after at least 36 months. MATERIALS AND METHODS: Twenty-five patients were treated with a maxillary implant-supported bar-retained overdenture on four different implant types: internal connection with microthreads (I-MT), internal connection without microthreads (I-NMT), external connection with microthreads (E-MT), and external connection without microthreads (E-NMT). To control confounding factors, all other design features were similar. A linear mixed-model analysis or mixed-model logistic regression analysis was used to determine the effect of implant type on bone level, probing pocket depth, bleeding on probing, and plaque. RESULTS: Four out of 98 implants (4.1%) placed in 25 patients failed during provisionalization and were replaced. Mean overall bone loss after 6 months was 0.39 mm (SD 0.62, range 0.00-3.48) with limited additional bone loss of 0.04 mm (SD 0.54, range -1.80-1.63) after at least 3 years. Microthreads or connection type had no effect on the bone level, probing pocket depth, bleeding on probing, nor plaque. CONCLUSIONS: With 96% of implant survival, the maxillary overdenture supported with a bar on four implants yield a predictable outcome and the implant-abutment connection type (internal vs external) and implant neck design (microthreaded vs non-microthreaded) have no influence on peri-implant bone remodeling after initial bone remodeling nor up to 4 years of function. Peri-implant bone levels are within international success standards and peri-implant health is indicative of absence of peri-implantitis.

The Long-Term Effect of Adapting the Vertical Position of Implants on Peri-Implant Health: A 5-Year Intra-Subject Comparison in the Edentulous Mandible Including Oral Health-Related Quality of Life.

Despite high success rates of dental implants, surface exposure may occur as a consequence of biologic width establishment associated with surgery. This prospective split-mouth study evaluated the effect of early implant surface exposure caused by initial bone remodeling on long-term peri-implant bone stability and peri-implant health. Additionally, Oral Health-Related Quality of Life (OHRQoL) was assessed by means of the Oral Health Impact Profile-14 (OHIP-14). Twenty-six patients received two non-splinted implants supporting an overdenture in the mandible by means of locators. One implant was installed equicrestally (control) and the second one was installed subcrestally, taking at least 3 mm soft tissue thickness into account (test). During initial bone remodeling (up to 6 months postoperatively), equicrestal placement yielded 0.68 mm additional surface exposure compared to subcrestal placement (p < 0.001). Afterwards, bone level and peri-implant health were comparable in both treatment conditions and stable up to 5 years. The implant overdenture improved OHRQoL (p < 0.01) and remained unchanged thereafter (p = 0.51). In conclusion, adapting the vertical position of the implant concerning the soft tissue thickness prevents early implant surface exposure caused by initial bone remodeling, but in a well-maintained population, this has no impact on long-term prognosis. The treatment of edentulousness with an implant mandibular overdenture improves OHRQoL.

Five years follow-up of mandibular 2-implant overdentures on locator or ball abutments: Implant results, patient-related outcome, and prosthetic aftercare.

BACKGROUND: It is uncertain, which is the optimal attachment for a mandibular 2-implant overdenture (2IOD). PURPOSE: To assess 5 years clinical implant outcome, prosthetic maintenance, cost, and PROMs of two cohorts receiving 2IOD on ball or stud abutments in a comparative study. MATERIALS AND METHODS: Ninety edentulous individuals were treated with balls (n = 34) or locator (n = 56). Implant survival, bone-to-implant level, prosthetic outcome, technical maintenance, and OHIP-14 were assessed. Statistics to compare between baseline and 1/5 years and between groups were t-test or Mann-Whitney (P < .05); chi-square was adopted to analyze plaque and technical maintenance or interventions between groups. RESULTS: Five years implant survival was 98.7%, irrespective of attachment. Overall mean bone loss was 1.1 mm, probing pocket depth 1.92 mm, bleeding score 0.60, plaque score 1. Plaque accumulated more on locators (P = .023). OHIP-14 declined from 18.1 to 2.7 irrespective of attachment. Retention for balls was better (P < .005), locators required more maintenance (P < .001), caused by retention-adjustment (P < .001) or ulcers/pain (P = .014). Five years maintenance-cost was 11% of initial cost, irrespective of attachment. CONCLUSIONS: Balls and locators yield stable 5-years implant outcome and improved Oral Health Related Quality of Life (OHRQoL). Locators required more maintenance and resulted in a lower retention. Maintenance costs are minimal but may affect OHRQoL at least for stud abutments.

Improvement of Quality of Life with Implant-Supported Mandibular Overdentures and the Effect of Implant Type and Surgical Procedure on Bone and Soft Tissue Stability: A Three-Year Prospective Split-Mouth Trial.

In fully edentulous patients, the support of a lower dental prosthesis by two implants could improve the chewing ability, retention, and stability of the prosthesis. Despite high success rates of dental implants, complications, such as peri-implantitis, do occur. The latter is a consequence of crestal bone loss and might be related to the implant surface and peri-implant soft tissue thickness. The aim of this paper is to describe the effect of implant surface roughness and soft tissue thickness on crestal bone remodeling, peri-implant health, and patient-centered outcomes. The mandibular overdenture supported by two implants is used as a split-mouth model to scrutinize these aims. The first study compared implants placed equicrestal to implants placed biologically (i.e., dependent on site-specific soft tissue thickness). The second clinical trial compared implants with a minimally to a moderately rough implant neck. Both studies reported an improvement in oral health-related quality of life and a stable peri-implant health after three years follow-up. Only equicrestal implant placement yielded significantly higher implant surface exposure, due to the establishment of the biologic width. Within the limitations of this study, it can be concluded that an implant supported mandibular overdenture significantly improves the quality of life, with limited biologic complications and high survival rates of the implants.

A one-year prospective study on alveolar ridge preservation using collagen-enriched deproteinized bovine bone mineral and saddle connective tissue graft: A cone beam computed tomography analysis.

BACKGROUND: Although there is ample research on alveolar ridge preservation (ARP), changes of the soft tissue profile are seldom reported. In addition, the use of a saddle connective tissue graft (S-CTG) has only been described in one study. PURPOSE: To evaluate changes in bone and external soft tissue profile following ARP of intact and nonintact sockets using collagen-enriched deproteinized bovine bone mineral (C-DBBM) and a S-CTG (a); to assess the need for additional hard and soft tissue grafting after ARP (b). MATERIALS AND METHODS: Patients in need of a single or multiple unit fixed reconstruction in the premaxilla were included in this prospective case series. After tooth extraction, sockets were grafted with C-DBBM and sealed with a S-CTG. Cone beam computed tomography slides taken before tooth extraction and 4 to 6 months after ARP were superimposed to measure changes in bone dimensions and external soft tissue profile. The need for additional hard and soft tissue grafting was registered. Implants were evaluated at 1 year. Patient-reported outcomes were registered on a 100 mm visual analogue scale at suture removal and 1 year following ARP. RESULTS: Nineteen teeth (10 with intact sockets, 9 with nonintact sockets) in 14 patients (11 females; mean age 34) were extracted and treated with the abovementioned protocol. Volume loss could not be prevented and mainly occurred at the buccal aspect. Maximum horizontal bone resorption was 1.27 mm and maximum horizontal shrinkage of the soft tissue profile amounted to 0.87 mm, both at the most cervical aspect. Additional GBR was necessary in two sites with a nonintact buccal bone wall. The need for additional soft tissue grafting was moderate in sites with intact (3/10) and high in nonintact sockets (6/9). Implants demonstrated favorable clinical and esthetic outcomes. Pain intensity and patient satisfaction were 17 and 94, respectively. CONCLUSION: Alveolar ridge preservation was not able to prevent relevant tissue changes. However, implants could be installed as planned. Although the application of a S-CTG partly compensated for the buccal bone loss, the need for additional soft tissue grafting was still moderate in intact sockets and high in nonintact sockets.

Long-Term Effect of Surface Roughness and Patients' Factors on Crestal Bone Loss at Dental Implants. A Systematic Review and Meta-Analysis.

Publications from 2011 to 2015 were selected to evaluate effect of implant surface roughness on long-term bone loss as surrogate for peri-implantitis risk. 87 out of 2,566 papers reported the mean bone loss after at least 5 years of function. Estimation of the proportion of implants with bone loss above 1, 2, and 3 mm as well as analysis the effect of implant surface roughness, smoking, and history of periodontitis was performed. By means of the provided statistical information of bone loss (mean and standard deviation) the prevalence of implants with bone loss ranging from 1 to 3 mm was estimated. The bone loss was used as a surrogate parameter for "peri-implantitis" given the fact that "peri-implantitis" prevalence was not reported in most studies or when reported, the diagnostic criteria were unclear or of dubious quality. The outcome of this review suggests that peri-implant bone loss around minimally rough implant systems was statistically significant less in comparison to the moderately rough and rough implant systems. No statistically significant difference was observed between moderately rough and rough implant systems. The studies that compared implants with comparable design and different surface roughness, showed less average peri-implant bone loss around the less rough surfaces in the meta-analysis. However, due to the heterogeneity of the papers and the multifactorial cause for bone loss, the impact of surface roughness alone seems rather limited and of minimal clinical importance. Irrespective of surface topography or implant brand, the average weighted implant survival rate was 97.3% after 5 years or more of loading. If considering 3 mm bone loss after at least 5 years to represent the presence of "peri-implantitis," less than 5% of the implants were affected. The meta-analysis indicated that periodontal history and smoking habits yielded more bone loss.