Immediate loading of mandibular overdentures supported by unsplinted direct laser metal-forming implants: results from a 1-year prospective study

Background: At present, only some studies have dealt with immediate loading of unsplinted implants supporting mandibular overdentures. The aim of this prospective study is to evaluate treatment outcomes of mandibular overdentures supported by four one‐piece, unsplinted, immediately loaded, direct laser metal‐forming (DLMF) implants by assessing implant survival rate, implant success, marginal bone loss, and prosthetic complications. Methods: A total of 96 one‐piece DLMF implants were inserted in the edentulous mandible of 24 patients. Four implants were placed in each edentulous mandible. Immediately after implant placement, a mandibular overdenture was connected to the implants. At 1‐year follow‐up, clinical, radiographic, and prosthetic parameters were assessed. Success criteria included absence of pain, suppuration, and implant mobility; absence of continuous peri‐implant radiolucency; and distance between the implant shoulder and the first visible bone contact <1.5 mm. Results: After a 1‐year loading time, the overall implant survival rate was 98.9%, with only one implant lost. Among the surviving 95 implants, two did not fulfill the success criteria; therefore, the implant success rate was 97.8%. The mean distance between the implant shoulder and the first visible bone contact was 0.28 ± 0.30 mm (95% confidence interval, 0.24 to 0.32). Some prosthetic complications were reported. Conclusion: Based on the present results and within the limits of this study, the immediate loading of four unsplinted DLMF implants by means of ball attachment–supported mandibular overdentures seems to represent a safe and successful procedure.     

Short implants (5‐8 mm) vs long implants (≥10 mm) with augmentation in atrophic posterior jaws: A meta‐analysis of randomised controlled trials

The aim of this systematic review was to compare the survival rate, marginal bone loss changes and complications between short implants (5‐8 mm) and long implants (≥10 mm) with a bone‐augmented procedure in the posterior jaw. An electronic search of the MEDLINE (PubMed), Embase and Cochrane Library databases through September 2018 was done to identify randomised controlled trials (RCT) assessing short implants and long implants with at least a 1‐year follow‐up period after loading. A quantitative meta‐analysis was conducted on the survival rate, marginal bone loss changes and complications. Ten RCTs met the inclusion criteria. There were no significant differences in the survival rate (RR: 1.01; 95% CI: [0.99, 1.03]; P = .32) and complications (RR: 0.48; 95% CI: [0.20, 1.17]; P = .11) between the two groups. Compared with the long implant group, the short implant group had a lower marginal bone loss change, and the effect measure was significant (mean difference: ?0.13; 95% CI: [?0.20, ?0.06]; P < .05). This systematic review showed no difference between the survival rates and complications of short implants (5‐8 mm) and long implants (≥10 mm). The marginal bone loss changes in short implants are lower than those in long implants.     

Stability and marginal bone level measurements of unsplinted implants used for mandibular overdentures: a 1-year randomized prospective clinical study comparing early and conventional loading protocols

Objectives: The aim of this study was to compare the performance of two non‐splinted implants used as retention for a mandibular overdenture when applying conventional or early loading protocols. Material and methods: Twenty edentulous patients were treated with two unsplinted and non‐submerged implants (15 mm long, TiUnite RP, Brånemark System) in the anterior mandible. The patients were randomly allotted into two groups: (i) test group (Group A), in which the overdenture was connected 1 week after surgery, and (ii) control group (Group B), in which the overdenture was connected after 12 weeks of healing. Resonance frequency analyses (RFA) for implant stability measurements were performed at implant surgery and after 1, 3, 6, 9 and 12 months. Marginal bone levels were evaluated at implant surgery and after 6 and 12 months. Results: No implant from either group was lost and all implants showed less than 1 mm of marginal bone resorption during the first year. The mean implant stability quotient (ISQ) values at implant surgery were 76.2±2.8 for Group A and 75.6±4.5 for Group B. The 12‐month measurements showed 76.4±2.5 ISQ and 76.4±2.8 ISQ for Groups A and B, respectively. There were no statistically significant changes between or within the groups with time. There were no differences in marginal bone loss, which was on average 0.3 mm for both groups after 1 year. Conclusion: Although a limited number of patients were followed for 1 year only, the results of the present study indicate that early loading of two unsplinted 15 mm long implants with an overdenture does not negatively affect implant stability or marginal bone conditions when compared with implants subjected to 12 weeks of healing before loading.     

Marginal Bone Level Changes and Prosthetic Maintenance of Mandibular Overdentures Supported by 2 Implants: A 5‐Year Randomized Clinical Trial

Background: Documentation of early loading of mandibular overdentures supported by different implant systems is scarce. Purpose: This study aimed to compare the biologic and prosthetic outcome of mandibular overdentures supported by unsplinted early‐loaded one‐ and two‐stage oral implants after 5 years of function. Materials and Methods: Twenty‐eight consecutive patients were screened following an inclusion and exclusion criteria, and randomly allocated to treatment groups. Ball‐retained mandibular overdentures were fabricated on two unsplinted Straumann® (Institut Straumann AG, Basel, Switzerland) and Brånemark® (Nobel Biocare AB, Göteborg, Sweden) dental implants and subjected to an early‐loading protocol. During the 5‐year period, prosthetic complications were recorded. At 5‐years of function, plaque, peri‐implant inflammation, bleeding, and calculus index scores were recorded, and standard periapical radiographs were obtained from each implant for measurement of marginal bone loss. Results: All implants survived during the observation period. The peri‐implant inflammation, bleeding, and calculus index scores around Straumann and Brånemark implants were similar (p > .05). The marginal bone loss around Brånemark implants (1.21 ± 0.1) was higher than Straumann implants (0.73 ± 0.06) at 5 years of function (p = .002). Kaplan–Meier tests revealed that 1‐ and 5‐year survival of overdentures on Straumann and Brånemark implants were similar (p = .85). Wear of the ball abutment in the Brånemark group was higher than in the Straumann group (p < .05). Complications regarding the retainer and the need for occlusal adjustments were higher in the Straumann group (p < .05). Chi‐square test revealed that the frequency of retightening of the retainer was higher in the Straumann group than in the Brånemark group (p < .05). Conclusions: Mandibular overdentures supported by unsplinted early‐loaded Straumann and Brånemark implants lead to similar peri‐implant soft tissue and prosthetic outcomes, although higher marginal bone loss could be observed around Brånemark implants after 5 years.     

A 5‐year randomized clinical trial on the influence of splinted and unsplinted oral implants in the mandibular overdenture therapy. Part I: peri‐implant outcome.

Thirty-six completely edentulous patients were enrolled for a 5-year prospective study testing the treatment outcome between splinted and unsplinted implants retaining a mandibular hinging overdenture. The patients were randomized into 3 groups of equal size depending on the attachment system used such as: magnets, ball attachments or bars (reference group). Only 1 implant out of the 72 had failed at the abutment stage. Not a single implant failed during the 5-year loading period. The accumulation of plaque was significantly higher for the Magnet than for the Ball group. Bleeding on probing, as well as marginal bone level, attachment level and Periotest values did not statistically differ among the groups, neither at year 1 nor at year 5. However, the Periotest values were significantly lower at year 5 compared to year 1 for all groups, which indicates a higher rigidity at the bone-implant interface. No correlation was found between bleeding on probing and marginal bone loss. We conclude that the connection state of 2 implants retaining a hinging overdenture did not influence the peri-implant outcome.     

To splint or not to splint oral implants in the implant‐supported overdenture therapy? A systematic literature review

The objective of this systematic review was to assess the influence of splinted and unsplinted oral implants in the mandibular and maxillary implant-supported overdenture therapy, concerning the implant survival, the peri-implant parameters, the prosthetic complications and the patient satisfaction. An electronic MEDLINE search complemented by manual searching was conducted to identify randomized clinical trials, prospective and retrospective cohort studies on implant-supported overdentures with a mean follow-up of at least 3 years. Twelve studies from an initial yield of 1022 titles were finally selected and data were extracted. After an observation period of more than 3 years, there was no difference in implant survival rates between splinted and unsplinted design. From most of the investigations included in this study, it was mentioned that the unsplinted design needs more prosthetic maintenance. In more of the studies that were dealing with the satisfaction of the patients wearing implant-supported overdentures, no significant difference in the preference of the patients was reported. No significant difference in the peri-implant outcome between splinted and unsplinted design was found. Within the limits of this systematic review, it is concluded that there was no significant difference between the two different designs of implant-supported overdentures with respect to the soft tissue health status or patient satisfaction, although the bar-supported overdentures have been shown to need less prosthetic maintenance.     

Immediate Loading of Mandibular Overdentures Supported by One‐Piece,Direct Metal Laser Sintering Mini‐Implants: A Short‐Term Prospective Clinical Study

Background: Only a few studies have dealt with immediately loaded, unsplinted mini‐implants supporting ball attachment–retained mandibular overdentures (ODs). The aim of this study is to evaluate treatment outcomes of ball attachment–retained mandibular ODs supported by one‐piece, unsplinted, immediately loaded, direct metal laser sintering (DMLS) mini‐implants. Methods: Over a 4‐year period (2009 to 2012), all patients referred to the Dental Clinic, University of Varese, and to a private practice for treatment with mandibular ODs were considered for inclusion in this study. Each patient received three or four DMLS mini‐implants. Immediately after implant placement, a mandibular OD was connected to the implants. At each annual follow‐up session, clinical and radiographic parameters were assessed, including the following outcome measures: 1) implant failures; 2) peri‐implant marginal bone loss; and 3) complications. Statistical analysis was conducted using a life‐table analysis. Results: A total of 231 one‐piece DMLS mini‐implants were inserted in 62 patients. After 4 years of loading, six implants failed, giving an overall cumulative survival rate of 96.9%. The mean distance between the implant shoulder and the first visible bone‐to‐implant contact was 0.38 ± 0.25 and 0.62 ± 0.20 mm at the 1‐ and 4‐year follow‐up examinations, respectively. An incidence of 6.0% of biologic complications was reported; prosthetic complications were more frequent (12.9%). Conclusions: Within the limits of this study, it can be concluded that the immediate loading of one‐piece, unsplinted, DMLS titanium mini‐implants by means of ball attachment–supported mandibular ODs is a successful treatment procedure. Long‐term follow‐up studies are needed to confirm these results.     

Should the restoration of adjacent implants be splinted or nonsplinted? A systematic review and meta-analysis

Statement of problem

The decision to splint or to restore independently generally occurs during the planning stage, when the advantages and disadvantages of each clinical situation are considered based on the proposed treatment. However, clinical evidence to help clinicians make this decision is lacking.

Clinical and radiological results of patients treated with two loading protocols for mandibular overdentures on Brånemark implants

Objective: The aim of this study was to evaluate clinical and radiological outcomes of the unsplinted implants supporting mandibular overdenture when applying conventional or early loading protocols. Material and Methods: Twenty‐six edentulous patients were treated with two unsplinted Brånemark System implants supporting mandibular overdenture. There was a test group, in which the overdenture was connected 1 week after surgery, and a control group, in which the overdenture was connected 3 months after surgery. Peri‐implant paremeters were recorded 1, 6, and 12 months after surgery. Clinical stability measurements were performed at surgery, and after 3, 6, and 12 months. Marginal bone levels were evaluated at implant surgery, after 6, and after 12 months. Results: No implant from either group was lost. Clinical peri‐implant parameters, clinical stability measurements, and marginal bone resorptions showed no statistically significant differences between two groups during 12 months. Conclusion: The results of this study suggest that one‐week of early loading protocol of two Brånemark implants supporting mandibular overdenture does not compromise implant stability, marginal bone loss, and peri‐implant soft‐tissue health.     

Long‐term clinical and prosthetic outcomes of soft liner and clip attachments for bar/implant overdentures: a randomised controlled clinical trial

Long‐term clinical and prosthetic outcomes of soft liner attachments for bar/implant overdentures were not sufficiently investigated. The aim of this trial was to evaluate clinical and prosthetic outcomes of resilient liner and clip attachments for bar/implant‐retained mandibular overdenture after 7 years. Thirty edentulous male participants received two implants in the canine areas of the mandible. Three months later, implants were splinted with a resilient bar. Mandibular overdentures were connected to the bars with either clip (CR group, n = 15) or resilient liner (RR group, n = 15) attachments. Plaque index (PI), gingival index (GI), probing depth (PD), vertical bone loss (VBL), horizontal bone loss (HBLO) and prosthetic complications (PCs) were evaluated at denture delivery (T0), 6 (T_6m), 12 (T1), 24 (T2), 36 (T3), 48 (T4), 60 (T5), 72 (T6) and 84 (T7) months after insertion. PI and GI increased significantly with time for CR and decreased significantly for RR (P < 0·001). PD increased at T1 (CR) and T6 m (RR) and then decreased thereafter (P < 0·05). VBL increased significantly with time in both groups (P < 0·005). HBLO increased at T2 (CR) and T1 (RR) and then decreased thereafter. CR recorded significant higher PI, GI, PD, VBLO and HBLO compared to RR at all observation times (P < 0·042). The survival rates were 96·6% and 100% for CR and RR after 7 years. The most common PCs for CR and RR were clip wears and separation of the resilient liner from the denture base, respectively. Within the limitations of this study, resilient liner attachments are recommended for bar/implant‐retained mandibular overdentures than clip attachments in terms of peri‐implant tissue health and prosthetic complications after 7 years.     

A 2-year clinical report of patients treated with two loading protocols for mandibular overdentures: early versus conventional loading

BACKGROUND: The original Br?nemark protocol for dental implant treatment was based on submerged healing prior to loading. In recent years, immediate/early functional loading has been reported to be possible with high success for various indications including two splinted mandibular implants supporting an overdenture. However, there are a limited number of studies regarding the early loading protocol for two unsplinted mandibular implants supporting an overdenture. METHODS: A total of 26 edentulous patients were treated with two unsplinted dental implants supporting mandibular overdentures. All implants were placed in the canine regions of each mandible according to the one-stage surgery. For the test group, overdentures were connected 1 week after surgery, and for the control group, overdentures were connected 3 months after surgery. Peri-implant parameters were recorded 1, 6, 12, 18, and 24 months after surgery. Marginal bone levels were evaluated at implant placement and after 6, 12, 18, and 24 months. Clinical stability measurements were performed at surgery, and after 3, 6, 12, 18, and 24 months. RESULTS: No implant from either group was lost during 2 years. Clinical peri-implant parameters, clinical implant stability measurements, and marginal bone resorptions showed no statistically significant differences between the two groups during 24 months. CONCLUSION: The results of this clinical trial suggest that the early loading approach of two dental implants supporting a mandibular overdenture does not jeopardize peri-implant soft tissue health, marginal bone resorption, and implant stability.     

A 10-year randomized clinical trial on the influence of splinted and unsplinted oral implants retaining mandibular overdentures: peri-implant outcome

PURPOSE: This randomized controlled clinical trial aimed to evaluate the efficacy of splinted implants versus unsplinted implants in overdenture therapy over a 10-year period. MATERIALS AND METHODS: The study sample comprised 36 completely edentulous patients, 17 men and 19 women (mean age 63.7 years). In each patient, 2 implants (Br?nemark System, Nobel Biocare, G?teborg, Sweden) were placed in the interforaminal area. Three to 5 months after placement, they were connected to standard abutments. The patients were then rehabilitated with ball-retained overdentures, magnet-retained overdentures, or bar-retained overdentures (the control group). Patients were followed for 4, 12, 60, and 120 months post-abutment connection. Group means as well as linear regression models were fitted with attachment type and time as classification variables and corrected for simultaneous testing (Tukey). RESULTS: After 10 years, 9 patients had died and 1 was severely ill. Over 10 years, no implants failed. Mean Plaque Index, Bleeding Index, change in attachment level, Periotest values, and marginal bone level at the end of the follow-up period were not significantly different among the groups. DISCUSSION: The annual marginal bone loss, excluding the first months of remodeling, was comparable with that found around healthy natural teeth. CONCLUSION: The fact that no implants failed and that overall marginal bone loss after the first year of bone remodeling was limited suggested that implants in a 2-implant mandibular overdenture concept have an excellent prognosis in this patient population, irrespective of the attachment system used.     

A clinical comparison of prosthetic complications of implant-supported overdentures with different attachment systems

OBJECTIVES: The objective of this clinical study was to evaluate the prosthetic complications of patients with 2 to 4 implants splinted with a round bar or with 2 to 4 unsplinted implants with ball attachments during the follow-up period. METHODS: A total of 26 patients were included in this study. Patients were randomly provided with a round bar or with ball attachments that were used to retain overdentures. During follow-up visits, the following prosthetic complications were recorded: round bar fracture, fractured overdenture, hygiene complications, abutment screw loose, worn O-ring or replacement of O-ring attachment, and fractured retention clip. The functioning period of overdentures in the round bar group ranged from 12 to 72 months (mean 49), and from 12 to 40 months (mean 23) in the ball attachment group. RESULTS: A total of 20 prosthetic complications were recorded in both groups. No differences in prosthetic complications were observed for 2 attachment systems. CONCLUSION: Implant-supported overdentures with bar or ball attachments may be considered to be reliable methods in the treatment of the edentulous individuals.     

Comparison between flapless and open-flap implant placement: a systematic review and meta-analysis

No consensus has been reached regarding the influence of the flapless and open-flap surgical techniques on the placement of dental implants. This systematic review compared the effects of flapless implant placement and implant placement with elevation of the mucoperiosteal flap in terms of marginal bone loss, implant survival rate and complications rates. This review followed PRISMA guidelines and was registered in PROSPERO with the registration number CRD42017071475. Two independent reviewers performed a comprehensive search of the PubMed/MEDLINE, Scopus, and Cochrane Library databases for studies published until December 2017. The search identified 559 references. After a detailed review, 24 studies were assessed for eligibility. A total of 1025 patients who had received a total of 1873 dental implants were included. There were no significant differences between the flapless and open-flap surgical techniques in terms of implant survival rates (P = 0.34; risk ratio (RR): 1.36; confidence interval (CI): 0.72–2.56), marginal bone loss (P = 0.23; MD: −0.20; CI: −0.52–0.13), or complication rates (P = 0.67; RR: 1.10; CI: 0.70–1.73). The current meta-analysis showed that the implant survival rate, marginal bone levels, and complications of flapless surgery were similar to those of open-flap surgery over a mean follow-up period of 21.62 months.     

A controlled clinical trial of implant-retained mandibular overdentures; five-years' results of clinical aspects and aftercare of IMZ implants and Brånemark implants

The aim of this prospective randomized controlled clinical trial was to evaluate a set of clinical items and prosthetic aftercare of edentulous patients with a mandibular overdenture retained by 2 IMZ implants or 2 Brånemark implants during a 5‐years' period. Patients were allocated to the IMZ group (n=29) or the Brånemark group (n=32) by a computerized balancing method. In the IMZ group 4 implants were lost during the 5‐years' follow‐up (survival rate: 93%). In the Brånemark group 9 implants were lost (survival rate: 86%). All patients were re‐operated successfully. Multiple prosthetic revisions were necessary in both groups, especially the precision attachment system in the overdenture was subject to frequent fracture or loosening. From this study can be concluded that there is no difference in clinical state, radiographical state, survival rate and clinical implant performance between the IMZ implant system and the Brånemark implant system supporting an overdenture on 2 implants after 5 years of follow‐up.     

Mandibular single‐implant overdentures: preliminary results of a randomised‐control trial on early loading with different implant diameters and attachment systems

Objectives: To determine surgical and prosthodontic outcomes of mandibular single‐implant overdentures, opposing complete maxillary dentures, using a wide diameter implant and large ball attachment system compared with different regular diameter implants with standard attachment systems. Materials and methods: Thirty‐six edentulous participants (mean age 68 years, SD 9.2) were randomly assigned into three treatment groups (n=12). A single implant was placed in the mandibular midline of participants to support an overdenture using a 6‐week loading protocol. The control group received Southern regular implants and standard ball attachments. One group received Southern 8‐mm‐wide implants and large ball attachments. Another group received Neoss regular implants and Locator attachments. Parametric and non‐parametric tests of a statistical software package (SPSS) were used to determine between groups differences in marginal bone loss, implant stability, implant, and prosthodontic success (P<0.05). Results: Implant success after 1 year was 75% for Southern regular implant (control) group; and 100% for the Southern wide and Neoss regular implant groups (P=0.038). Mean marginal bone loss at 1 year was 0.19 mm (SD 0.39) without significant differences observed. Implant stability quotient (ISQ) at baseline was significantly lower for the Southern regular (control) group than the other two groups (P=0.001; P=0.009). At 1 year, no significant difference in implant stability was observed (mean ISQ 74.6, SD 6.1). The change in implant stability from baseline to 1 year was significant for the control group (P=0.025). Prosthodontic success was comparable between the groups but the maintenance (41 events overall, mean 1.2) was greater for the Locator and the standard ball attachments. Conclusions: Mandibular single‐implant overdentures are a successful treatment option for older edentulous adults with early loading protocol using implants of different diameters and with different attachment systems. To cite this article:
Alsabeeha NHM, Payne AGT, De Silva RK, Thomson WM. Mandibular single‐implant overdentures: preliminary results of a randomised‐control trial on early loading with different implant diameters and attachment systems.
Clin. Oral Impl. Res. 22 , 2011; 330–337.
doi: 10.1111/j.1600‐0501.2010.02004.x     

A controlled clinical trial of implant-retained mandibular overdentures: 10 years' results of clinical aspects and aftercare of IMZ implants and Brånemark implants

Abstract: The aim of this prospective randomized controlled clinical trial was to evaluate the clinical outcomes and prosthetic aftercare of edentulous patients with a mandibular overdenture retained by two IMZ implants or two Brånemark implants during a 10‐year period. Patients were allocated to the IMZ group (n=29) or the Brånemark group (n=32) by a computerized balancing method. In the IMZ group, four implants were lost during the 10‐year follow‐up (survival rate: 93%). In the Brånemark group, nine implants were lost (survival rate: 86%). All patients were re‐operated successfully. Multiple prosthetic revisions were necessary in both groups; especially the precision attachment system in the overdenture (23% of the total number of revisions) and the denture base and teeth (26% of the total number of revisions) were subject to frequent fracture. From this study, it can be concluded that both the IMZ implant and the Brånemark implant systems supporting an overdenture are functioning well after 10 years of follow‐up. There are no indications of a worsening of clinical or radiographical state after 10 years.     

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. To cite this article:
Zembi? A, Johannesen LH, Schou S, Malo P, Reichert T, Farella M, Hämmerle CHF. Immediately restored one‐piece single‐tooth implants with reduced diameter: one‐year results of a multi‐center study.
Clin. Oral Impl. Res. 23 , 2012; 49–54.
doi: 10.1111/j.1600‐0501.2011.02174.x     

Comparison between computer-guided and freehand dental implant placement surgery: A systematic review and meta-analysis

The purpose of this systematic review was to compare computer-guided (fully guided) and freehand implant placement surgery in terms of marginal bone loss, complications, and implant survival. This review followed the PRISMA guidelines and was registered in the PROSPERO database (CRD42019135893). Two independent investigators performed the search of the PubMed/MEDLINE, Scopus, and Cochrane Library databases for studies published up to April 2020 and identified 1508 references. After a detailed review, only four studies were considered eligible. These studies involved a total of 154 patients with 597 dental implants and a mean follow-up period of 2.25 years. There was no difference between computer-guided surgery and freehand surgery in terms of the marginal bone loss (mean difference ?0.11 mm, 95% confidence interval (CI) ?0.27 to 0.04 mm; P = 0.16), mechanical complications (risk ratio (RR) 0.85, 95% CI 0.36–2.04; P = 0.72), biological complications (RR 1.56, 95% CI 0.42–5.74; P = 0.51), and implant survival rate (RR 0.53, 95% CI 0.11–2.43; P = 0.41). This meta-analysis demonstrated that both computer-guided and freehand surgeries yielded similar results for marginal bone loss, mechanical and biological complications, and implant survival rate.     

Long‐term,retrospective evaluation (implant and patient‐centred outcome) of the two‐implant‐supported overdenture in the mandible. Part 2: marginal bone loss

Objective: In part 2 of this long‐term, retrospective study on the two‐implant‐supported overdenture in the mandible, the annual marginal bone loss was evaluated in detail and parameters, with a significant effect on the annual bone loss, were verified. Material and methods: For all 495 patients with an overdenture in the mandible at least 5 years in function, data up to their last follow‐up visit had been collected, including long‐cone radiographs (taken at the abutment connection and after years 1, 3, 5, 8, 12 and 16 of loading) and probing data at their last evaluation. General information (medical history, implant data, report on surgery) was retrieved from the patient's file. Two hundred and forty‐eight patients had been clinically examined recently. For the others, information on bone level and probing depths were retrieved from the patient's files, as all patients had been enrolled in our annual follow‐up schedule. Results: The mean annual bone loss on a site level (without considering the first year of bone remodelling) after 3 years of loading was 0.08 mm/year (SD=0.22, n=1105), after 5 years of loading 0.07 mm/year (SD=0.14, n=892), after 8 years of loading 0.06 mm/year (SD=0.12, n=598), after 12 years 0.04 mm/year (SD=0.07, n=370) and 0.05 mm/year (SD=0.05, n=154) after 16 years of loading. Ongoing bone loss was seen in a number of implants (n=26) with the annual bone loss exceeding 0.2 mm. Some factors clearly showed a significant impact on bone loss: smoking (≥10 cigarettes/day), GBR, the presence of dehiscence and bone quantity(the latter only during the first year). The probing data showed a favourable condition, with <1.2% of the approximal pockets being ≥6 mm, and 4.1%=5 mm. Conclusions: The mean annual bone loss over the study period was <0.1 mm/year after the first year of loading. However, a small number (2.5%) of the implants showed continuing bone loss. To cite this article :
Vercruyssen M, Quirynen M. Long‐term, retrospective evaluation (implant and patient‐centred outcome) of the two‐implants‐supported overdenture in the mandible. Part 2: marginal bone loss.
Clin. Oral Impl. Res. 21 , 2010; 466–472.
doi: 10.1111/j.1600‐0501.2009.01902.x