Accuracy of immediately placed implants using surgical guides from different 3-dimensional printers: An in vitro study.

AIM: The aim of this study was to evaluate the accuracy of 3-dimensional (3D)-printed surgical guides for fully guided immediate implants from different manufacturers. METHODS: Eighteen 3D printed fully guided surgical guides (split into 3 groups [n = 6] according to their manufacturer: Company, Desktop, or Lab), were used to place 72 implants (n = 24) in identical maxillary models. After placement, the mean global, angular, mesiodistal, buccopalatal, and vertical deviation at the platform and apex of the placed implants, relative to their preoperatively planned positions, was calculated. RESULTS: Significant differences in global apex deviation, angular deviation, mesiodistal apex deviation, and vertical platform and apex deviation were found between the Lab and Desktop groups (p ≤ 0.007). Significant differences in mesiodistal platform and apex deviation and buccopalatal apex deviation were also found between the Company and Desktop groups (p ≤ 0.005). Finally, significant differences in buccopalatal apex deviation, and vertical platform and apex deviation were found between the Company and Lab groups (p ≤ 0.003). Mean differences between guide groups across all parameters never exceeded 0.5 mm or 1°. CONCLUSIONS: The choice of 3D printer has a significant effect on the accuracy of fully guided immediate implants. However, the clinical relevance of these differences may be considered limited.

A multi-centre randomized controlled trial comparing connective tissue graft with collagen matrix to increase soft tissue thickness at the buccal aspect of single implants: 3-Year results.

AIM: To compare connective tissue graft (CTG) with collagen matrix (CMX) in terms of increase in buccal soft tissue profile (BSP) when applied at single implant sites. MATERIALS AND METHODS: Patients with a single tooth gap in the anterior maxilla and horizontal mucosa defect were enrolled in a multi-centre randomized controlled trial. All were fully healed sites with a bucco-palatal bone dimension of at least 6 mm, and received an immediately restored single implant using a full digital workflow. Patients were randomly allocated to the control (CTG) or test group (CMX: Geistlich Fibro-Gide, Geistlich Pharma AG, Wolhusen, Switzerland) to increase buccal soft tissue thickness. Primary endpoints were increase in BSP at T1 (immediately postop), T2 (3 months), T3 (1 year) and T4 (3 years) based on superimposed digital surface models. Secondary endpoints included patient-reported, clinical and aesthetic outcomes. RESULTS: Thirty patients were included per group (control group: 15 males, 15 females, mean age 50.1 years; test group: 14 males, 16 females, mean age 48.2 years) and 50 could be re-examined at T4. The changes in BSP over time were significantly different between the groups (p < .001). At T4, the estimated mean increase in BSP amounted to 0.83 mm (95% confidence interval [CI]: 0.58-1.08) in the control group and 0.48 mm (95% CI: 0.22-0.73) in the test group. The estimated mean difference of 0.35 mm (95% CI: 0.06-0.65) in favour of the control group was significant (p = .021). No significant differences between the groups could be observed in terms of patients' aesthetic satisfaction (p = .563), probing depth (p = .286), plaque (p = .676), bleeding on probing (p = .732), midfacial recession (p = .667), Pink Esthetic Score (p = .366) and Mucosal Scarring Index (p = .438). However, CMX resulted in significantly more marginal bone loss (-0.43 mm; 95% CI: -0.77 to -0.09; p = .015) than CTG. CONCLUSIONS: CTG was more effective in increasing buccal soft tissue profile and resulted in less marginal bone loss than CMX. Therefore, CTG remains the gold standard to increase soft tissue thickness at implant sites. CLINICAL TRIAL REGISTRATION: This study was registered in ClinicalTrials.gov (NCT04210596).

A Multi-Centre Randomized Controlled Trial Comparing Connective Tissue Graft with Collagen Matrix to Increase Buccal Soft Tissue Thickness: A Cone-Beam CT Analysis.

(1) Aim: a cross-linked porcine-derived collagen matrix (CMX) has been developed for soft tissue augmentation. Although this grafting material does not require a second surgical site, recent findings have indicated deeper pockets, more marginal bone loss and more midfacial recession in the short term when compared to connective tissue graft (CTG). Hence, the aim of the present study was to evaluate the safety of CMX based on buccal bone loss over a one-year period. (2) Methods: Patients who were missing a single tooth in the anterior maxilla were included, in whom the failing tooth had been removed at least 3 months prior and who presented a horizontal mucosa defect. All sites had a bucco-palatal bone dimension of at least 6 mm as assessed on Cone-Beam Computed Tomography (CBCT) to ensure complete embedding of an implant by bone. All patients received a single implant and an immediate implant restoration using a full digital workflow. Sites were randomly allocated to the control (CTG) or test group (CMX) to increase buccal soft tissue thickness. All surgeries were performed by means of full thickness mucoperiosteal flap elevation, placing CTG and CMX in contact with the buccal bone wall. Safety was assessed by evaluating the impact of CTG and CMX on buccal bone loss over a one-year period using superimposed CBCT scans. (3) Results: thirty patients were included per group (control: 50% females, mean age 50; test: 53% females, mean age 48) and 51 (control: 25; test: 26) could be analyzed for buccal bone loss. At 1 mm apical to the implant-abutment interface (IAI), most horizontal resorption was found pointing to 0.44 mm in the control group and 0.59 mm in the test group. The difference of 0.14 mm (95% CI: -0.17-0.46) was not statistically significant (p = 0.366). At 3 mm and 5 mm apical to the IAI, the difference between the groups was 0.18 mm (95% CI: -0.05-0.40; p = 0.128) and 0.02 mm (95% CI: -0.24-0.28; p = 0.899), respectively. Vertical buccal bone loss amounted to 1.12 mm in the control group and 1.14 mm in the test group. The difference of 0.02 mm (95% CI: -0.53-0.49) was not statistically significant (p = 0.926). (4) Conclusions: In the short term, soft tissue augmentation with CTG or CMX results in limited buccal bone loss. CMX is a safe alternative to CTG. Longer follow-up is needed to assess the impact of soft tissue augmentation on buccal bone.

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.

A multi-centre randomized controlled trial comparing connective tissue graft with collagen matrix to increase soft tissue thickness at the buccal aspect of single implants: 1-year results.

AIM: To compare connective tissue graft (CTG) with collagen matrix (CMX) in terms of increase in buccal soft tissue profile (BSP) at 1 year when applied at single implant sites. MATERIALS AND METHODS: Patients with a single tooth gap in the anterior maxilla and horizontal mucosa defect were enrolled in a multi-centre randomized controlled trial. All sites had a bucco-palatal bone dimension of at least 6 mm, received a single implant and an immediate implant restoration using a full digital workflow. Sites were randomly allocated to the control (CTG) or test group (CMX) to increase buccal soft tissue thickness. The primary outcome was the increase in BSP at 1 year when compared with the pre-operative situation based on superimposed digital surface models. The changes in BSP over time were registered at a buccal area of interest reaching from 0.5 mm below the soft tissue margin to 4 mm more apical. Secondary outcomes included patient-reported, clinical and aesthetic outcomes. RESULTS: Thirty patients were included per group (control: 50% females, mean age 50.1; test: 53% females, mean age 48.2). The increase in BSP at 1 year was 0.98 mm (98.3% confidence interval [CI]: 0.75-1.20) for CTG and 0.57 mm (98.3% CI: 0.34 to 0.79) for CMX. The mean difference of 0.41 mm (98.3% CI: 0.12 to 0.69) in favour of CTG was significant (p < .001). Based on an arbitrarily chosen threshold for success of 0.75 mm increase in BSP, 89.7% of the patients in the control group and 10% of the patients in the test group were successfully treated (odds ratio = 77.90; 95% CI: 13.52 to 448.80; p < .001). Sites treated with CMX demonstrated 0.89 mm (98.3% CI: 0.49 to 1.30) more shrinkage between postop and 1 year than sites treated with CTG. In addition, CMX resulted in significantly more marginal bone loss (0.39 mm; 95% CI: 0.05 to 0.74; p = .026) than CTG. There were no significant differences between the groups in terms of patients' aesthetic satisfaction (p = .938), probing depth (p = .917), plaque (p = .354), bleeding on probing (p = .783), midfacial recession (p = .915), Pink Esthetic Score (p = .121) and Mucosal Scarring Index (p = .965). CONCLUSIONS: CTG remains the gold standard to increase soft tissue thickness at implant sites. Clinicians need to outweigh the benefits of CMX against considerable resorption of the graft. This study was registered in ClinicalTrials.gov (NCT04210596).

A multi-centre randomized controlled trial comparing connective tissue graft with collagen matrix to increase soft tissue thickness at the buccal aspect of single implants: 3-month results.

AIM: To compare connective tissue graft (CTG) with collagen matrix (CMX) in terms of changes over time in buccal soft tissue profile (BSP) when applied at single implant sites. MATERIALS AND METHODS: Patients with a single tooth gap in the anterior maxilla and horizontal mucosa defect were enrolled in a multi-centre randomized controlled trial. All sites had a bucco-palatal bone dimension of at least 6 mm and received a single implant and immediate implant restoration using a full digital workflow. Sites were randomly allocated to the control (CTG) or test group (CMX: Geistlich Fibro-Gide®, Geistlich Pharma AG, Wolhusen, Switzerland) to increase buccal soft tissue thickness. Primary outcome was increase in BSP at T1 (immediately after operation) and T2 (3 months) based on superimposed digital surface models. Secondary parameters included patient-reported clinical and aesthetic outcomes. RESULTS: Thirty patients were included per group (control: 50% females, mean age 50; test: 53% females, mean age 48). Even though surgeons applied thicker grafts when using CMX, sites treated with CMX demonstrated 0.78 mm (95% CI 0.41-1.14) more shrinkage between T1 and T2 than sites treated with CTG. The final increase in BSP was 1.15 mm (95% CI 0.88-1.43) for CTG and 0.85 mm (95% CI 0.58-1.13) for CMX. The mean difference of 0.30 mm (95% CI -0.01 to 0.61) at T2 in favour of CTG was of borderline significance (p = .054). There were no significant differences between the groups in terms of post-operative bleeding (p = .344), pain (p = .331), number of analgesics taken (p = .504), oedema (p = .227), and pink aesthetic score (p = .655). VAS for post-operative haematoma was 6.56 (95% CI 0.54-12.59) lower for CMX, and surgery time could be reduced by 9.03 min (95% CI 7.04-11.03) when applying CMX. However, CMX resulted in significantly more marginal bone loss (0.38 mm; 95% CI 0.15-0.60), deeper pockets (0.30 mm; 95% CI 0.06-0.54), and more mid-facial recession (0.75 mm; 95% CI 0.39-1.12) than CTG. CONCLUSIONS: CTG remains the gold standard for increasing soft tissue thickness at the buccal aspect of 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.

Early peri-implant bone loss as a predictor for peri-implantitis: A 10-year prospective cohort study.

PURPOSE: To evaluate the effect of early bone loss (EBL), on long-term bone stability and future peri-implantitis development. MATERIALS AND METHODS: Patients referred for implant placement between 2005 and 2009 were consecutively treated and followed for 10 years. After 10 years, patients were invited for a scientific diagnostic visit to evaluate implant survival and bone loss. Bone level changes were compared with baseline. Non-parametric testing was performed in cross-tabs (Pearson Chi-square and Fishers's exact test). Kaplan-Meier-estimated survival curves were plotted for different thresholds for EBL at different timepoints. Generalized linear mixed models with binomial distribution and logit link for peri-implantitis were fitted. An adjusted logistic mixed model was made to evaluate peri-implantitis, in relation with smoking status, history of periodontitis, and EBL > 0.5 mm. RESULTS: Four hundred and seven patients (mean age of 64.86 years [range 28-92, SD 10.11]), with 1482 implants, responded to the 10-year recall invitation. After an average follow-up time of 10.66 years (range 10-14, SD 0.87), implant survival was 94.74%. Mean crestal bone loss after 10 years was 0.81 mm (SD 1.58, range 0.00-17.00). One hundred and seventy five implants in 76 patients had peri-implantitis (11.8% on implant level, 18.7% on patient level). EBL of 0.5, 1, and 2 mm were significant predictors for peri-implantitis and implant loss after 10 years. Implants with EBL ≥0.5 mm during the first year of function showed a 5.43 times higher odds for future peri-implantitis development. Probability in developing peri-implantitis was 52.06% when smoking, Periodontal history and EBL of >0.5 mm was combined. CONCLUSION: The present study suggests that EBL is a predictor for long-term peri-implant pathology, with a significant higher risk for peri-implantitis when early bone loss exceeds the thresholds of 0.5 and 1 mm, especially when additional risk factors such as smoking or susceptibility for periodontal disease prior to implant treatment are present. Clinical trial registration number B670201524796.

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.

A 5-year cohort study on early implant placement with guided bone regeneration or alveolar ridge preservation with connective tissue graft.

PURPOSE: To assess on the one hand the 5-year outcome of early implant placement with guided bone regeneration (EIP/GBR) and on the other hand of alveolar ridge preservation with late implant placement and connective tissue graft (ARP/CTG). MATERIALS AND METHODS: Patients who had been treated with a single implant in the anterior maxilla in 2014 were selected for reevaluation in 2019. In the EIP/GBR cohort, implants were installed 4 to 8 weeks following extraction and the buccal contour was overbuilt by means of GBR. In the ARP/CTG cohort, collagen-enriched deproteinized bovine bone mineral was applied at the time of extraction and implants were installed 5 months later. All ARP/CTG cases received a buccal CTG 3 months after implant installation to reestablish buccal convexity. Primary outcomes were the pink esthetic score (PES) (Belser et al 2009) and the mucosal scarring index (MSI) (Wessels et al 2019). Clinical and radiographical parameters were secondary outcomes. RESULTS: Eighteen patients (9 females; mean age 52) in the EIP/GBR cohort, and 20 patients (9 females; mean age 38) in the ARP/CTG cohort were evaluated. PES was 6.28 following EIP/GBR. A (nearly) perfect aesthetic outcome defined as PES ≥8 was found in 3/18 cases. Perfect root convexity / soft tissue color and texture seemed most difficult to achieve. PES was 7.80 following ARP/CTG. A (nearly) perfect aesthetic outcome was found in 11/20 cases. MSI was 2.94 following EIP/GBR with 14/18 cases showing scarring. MSI yielded 0.50 following ARP/CTG with 6/20 cases showing scarring. In both cohorts, all implants survived, and none had developed periimplantitis. However, implants in the ARP/CTG cohort demonstrated a 5.4 times higher risk for periimplant mucositis than implants in the EIP/GBR cohort at 5 years follow-up. CONCLUSION: EIP/GBR and ARP/CTG showed acceptable long-term outcomes. The aesthetic outcome was particularly favorable following ARP/CTG, yet this should be interpreted with caution due to selection bias and because soft tissue grafting was not performed in the EIP/GBR cohort. Randomized controlled trial (RCTs) comparing EIP with ARP are required to assess the need for soft tissue grafting and to evaluate clinical, aesthetic, volumetric, and patient-reported outcomes. Only on the basis of such studies clinical recommendations can be made.

The Long-Term Effect of Smoking on 10 Years' Survival and Success of Dental Implants: A Prospective Analysis of 453 Implants in a Non-University Setting.

BACKGROUND: The purpose of this study was to compare the survival and peri-implant bone loss of implants with a fluoride-modified surface in smokers and non-smokers. MATERIAL AND METHODS: All patients referred for implant treatment between November 2004 and 2007 were scrutinized. All implants were placed by the same surgeon (B.C.). The single inclusion criterion was a follow-up time of at least 10 years. Implant survival, health, and bone loss were evaluated by an external calibrated examiner (S.W.) during recall visits. Radiographs taken at recall visits were compared with the post-surgical ones. Implant success was based on two arbitrarily chosen success criteria for bone loss (≤1 mm and ≤2 mm bone loss after 10 years). Implant survival in smokers and non-smokers was compared using the log-rank test. Both non-parametric tests and fixed model analysis were used to assess bone loss in both groups. RESULTS: A total of 453 implants in 121 patients were included for survival analysis, and 397 implants in 121 patients were included for peri-implant bone-loss analysis. After a mean follow-up time of 11.38 years (SD 0.78; range 10.00-13.65), 33 implants out of 453 initially placed had failed in 21 patients, giving an overall survival rate of 92.7% and 82.6% on the implant and patient level, respectively. Cumulative 10 years' survival rate was 81% on the patient level and 91% on the implant level. The hazard of implant loss in the maxilla was 5.64 times higher in smokers compared to non-smokers (p = 0.003). The hazard of implant loss for implants of non-smokers was 2.92 times higher in the mandible compared to the maxilla (p = 0.01). The overall mean bone loss was 0.97 mm (SD 1.79, range 0-17) at the implant level and 0.90 mm (SD 1.39, range 0-7.85) at the patient level. Smokers lost significantly more bone compared to non-smokers in the maxilla (p = 0.024) but not in the mandible. Only the maxilla showed a significant difference in the probability of implant success between smokers and non-smokers (≤1 mm criterion p = 0.003, ≤2 mm criterion p = 0.007). Taking jaw into account, implants in smokers experienced a 2.6 higher risk of developing peri-implantitis compared to non-smokers (p = 0.053). CONCLUSION: Dental implants with a fluoride-modified surface provided a high 10 years' survival with limited bone loss. Smokers were, however, more prone to peri-implant bone loss and experienced a higher rate of implant failure, especially in the upper jaw. The overall bone loss over time was significantly higher in smoking patients, which might be suggestive for a higher peri-implantitis risk. Hence, smoking cessation should be advised and maintained after implant placement from the perspective of peri-implant disease prevention.

Long-Term Follow-up on Root Coverage with a Double Pedicle Flap and Connective Tissue Graft.

Partial-thickness double pedicle flap and connective tissue graft (CTG) is a procedure to treat single gingival recession in the anterior mandible. However, long-term data have not been reported. Patients who had been treated by the same periodontist in a private practice in Belgium between 2002 and 2009 were invited to return for a clinical examination in 2017. Seventeen patients (15 females, 2 males; mean age: 34.6 years) with a total of 23 treated single recessions were reexamined after 8 to 15 years of follow-up. Between 1 and 8 to 15 years of follow-up, mean and complete root coverage did not differ and amounted to 75% and 44% at study termination, respectively (P = .204). The esthetic outcome was mediocre, given a final mean root coverage esthetic score of 6.52. The Mucosal Scarring Index demonstrated a significant reduction in scarring between 1 and 8 to 15 years of follow-up; however, 31% of the cases still demonstrated some scarring in the end. Patients were less critical than clinicians, as they expressed high esthetic (mean: 81) and low scarring (mean 14) scores on visual analog scales. Partial-thickness double pedicle flap and CTG is an effective root-coverage procedure. However, alternative techniques may need to be considered for esthetically demanding patients.

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.

Five-year study of mandibular overdentures on stud abutments: Clinical outcome, patient satisfaction and prosthetic maintenance-Influence of bone resorption and implant position.

OBJECTIVES: This prospective study analyses the 5-year clinical outcome, patient satisfaction and the technical outcome of a 2-implant overdenture on stud abutments. In addition, the influence of mandibular resorption and implant position on these outcomes was assessed. MATERIAL AND METHODS: Patients received two implants in a one-stage delayed protocol. Final prosthesis on stud abutments was finalized after 3 months. Implant survival, bone loss, plaque and sulcus bleeding index, OHIP-14, technical outcome and costs were assessed after 5 years. The Cawood-Howell classification defined the mandibular resorption. Inter-implant distances and angles (frontal, sagittal) were digitally measured. The significance level was p < .05. RESULTS: Fifty-six patients, 23 female and 33 males (mean age = 66.3, range 41-82), completed the follow-up. No implants were lost. Radiographical crestal bone loss was on average 1.25 mm (standard deviation SD 1.06), bleeding index was 0.75 (SD 0.73), and plaque index was 1.15 (SD 0.75) and higher for low mandibles (p = .001). The OHIP-14 reduction post-connection and after 5 years was significant (p < .001). Five-year maintenance required on average 6.7 (SD 4.8, range 0-25) interventions per patient. A larger inter-implant distance was associated with fewer replacement of retention inserts (p = .034) and less interventions (p = .006). Larger frontal (p = .023) and sagittal (p = .046) inter-implant angles (non-parallelism) required more inserts. The maintenance cost negatively influences the patient satisfaction (p = .004). 83% of the stud abutments showed wear. CONCLUSION: The implant overdenture on cylindrical stud abutments is a good and stable solution, irrespective of the resorption profile of the mandible. OHIP-14 improved permanently up to 5 years but is negatively influenced by complication cost. A small inter-implant distance, more frontal, sagittal inter-implant divergence increased maintenance.

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.

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.

A randomized controlled clinical trial assessing initial crestal bone remodeling of implants with a different surface roughness.

PURPOSE: The aim of current split-mouth study is to compare crestal bone loss of hybrid with moderately rough implants in patients with a bar-supported mandibular overdenture. MATERIALS AND METHODS: Fully edentulous patients were enrolled for treatment with implant-supported overdentures. Each patient received two implants of which one moderately rough (Sa: 1.3 µm) and one hybrid surface implant (moderately rough implant body [Sa: 1.3 µm] and a minimally rough implant neck [Sa: 0.9 µm]). Beside the difference in implant surface the two implants are identical. After 3 and 12 months, peri-apical radiographs were taken to assess crestal bone levels and a Wilcoxon signed-rank test was used for pairwise comparison. RESULTS: Forty-two implants were placed in 21 patients and no failures occurred after 1 year. An overall mean crestal bone loss of 0.40 mm (SD: 0.76; range: 0-3.93) and 0.35 mm (SD: 0.59; range: 0-2.56) was registered after a mean follow-up of 3.4 and 15.8 months. There was no statistical significant difference in crestal bone loss between the different implant surfaces or between the different time intervals. CONCLUSION: From this randomized controlled trial, it can be concluded that hybrid surface implants may be a viable alternative for implant treatment in the edentulous mandible.

Impact of crestal bone resorption on quality of life and professional maintenance with conventional dentures or Locator-retained mandibular implant overdentures.

STATEMENT OF PROBLEM: The influence of the mandibular resorption profile on clinical outcome after converting a conventional complete denture into a Locator-retained implant overdenture is unknown. PURPOSE: The purpose of this prospective study was to assess the oral health-related quality of life (OHRQoL) and prosthetic maintenance of mandibular overdentures on 2 Locator abutments in relation to the resorption degree of the edentulous mandible. MATERIAL AND METHODS: Twenty-five participants were treated and classified according to the Cawood and Howell (CAW-H) resorption classification for the resorption profile of the mandible, CAW-H group III-IV (n=14) and CAW-H group V (n=11). Participants received conventional complete dentures (CDs) before implant placement and immediate nonfunctional loading on Locators with a resilient liner. After 3 months, the attachments were functionally activated. Assessments were made using the Oral Health Impact Profile 14 (OHIP-14) questionnaires with existing CDs and new CDs at 1, 3, and 15 months after loading. Prosthetic maintenance (repairs, rebasings, replacement of retention parts) and biological prosthetic aftercare were assessed. For comparison between groups, the Kruskal-Wallis and Mann-Whitney U tests were applied for continuous and ordinal variables and the chi-square test for cross-tabulations. To analyze repeated OHIP-14 scores, the Friedman test was used for ordered alternatives to test whether the measurements differed (overall significance level α=.05). Then the Wilcoxon signed rank test was conducted to detect specific differences (α=.05). RESULTS: OHIP-14 scores decreased significantly after implant placement and functional connection for the whole population (P<.001) and for both sub groups, the CAW-H group III-IV (P<.001) and the CAW-H group V (P=.013). CAW-H group V participants needed more retention inserts than CAW-H group III-IV participants (26 versus 3, respectively; P=.006). The incidence of repair and rebasing was limited for both groups, and biological aftercare and pain relief were comparable. CONCLUSIONS: Changing a CD to an overdenture significantly improved ORLQoL regardless of the resorption degree, but heavily resorbed mandibles require more replacements of retention inserts.

Ten-year follow-up of dental implants used for immediate loading in the edentulous mandible: A prospective clinical study.

PURPOSE: The purpose of this study is to evaluate the 10-year outcome of 25 patients with immediate loading in the edentulous mandible. MATERIAL AND METHODS: Twenty-five patients were consecutively treated with 5 immediately loaded fluoride-modified implants in the edentulous mandible. Implant survival and bone loss were evaluated by an external researcher comparing digital periapical radiographs taken during recall visits with baseline (at implant insertion). Statistical descriptive analysis and nonparametric tests were performed using SPSS v23, multilevel analysis was performed by means of R version 3.1.0. to identify risk factors for bone loss. RESULTS: Twenty-one patients (8 males, 13 females, mean age 68.4, range 49-84) responded to the 10-year recall invitation. No implants were lost during follow-up, resulting in a 100% survival rate. After 10 years, bleeding on probing and plaque were present at 49.5% and 67.6% of the sites, respectively. The mean pocket probing depth was 3.77 mm (SD 0.73, range 3.0-6.83). Bone loss on implant level after 3, 12, 24, and 120 months was 0.16 mm (SD 0.33, range 0-1.75), 0.14 mm (SD 0.24, range 0-1.05), 0.17 mm (SD 0.27, range 0-1.5), and 0.49 mm (SD 1.08, range 0-7.8). Five implants were identified with or at risk for progressive bone loss. Forty-seven percent of the implants did not show any bone loss after 10 years in function and 87% lost less than 1 mm. Multilevel statistical analysis identified 2-year bone loss as a predictor for bone loss after 10 years of function. CONCLUSION: Immediate loading of 5 fluoride-modified dental implants with a fixed prosthetic rehabilitation is a predictable and reliable treatment in the edentulous mandible, based on a 100% implant survival and limited peri-implant bone loss. Implants used for immediate loading in the edentulous mandible who are showing early bone loss may be at higher risk to develop peri-implantitis.

A randomized controlled clinical trial to assess crestal bone remodeling of four different implant designs.

BACKGROUND: It is claimed that bone remodeling is limited when the implant neck has microthreads and an internal abutment connection. However, comparative studies, excluding confounding factors, are scarce. AIM: This RCT aims to assess whether a coronal microthreaded design and an internal abutment connection affects crestal bone loss, up to one year of function. MATERIALS AND METHODS: Twenty-one maxillary edentulous patients were consecutively treated for a bar supported maxillary overdenture on four different implants with respectively: internal connection and microthreads on the implant neck (I MT); internal connection, no microthreads (I NMT), external connection, with microthreads (E MT), and external connection, without microthreads (E NMT). Other design features, s.a. width, surface topography, platform switch as well as surgical placement and prosthetic protocol were consistent. Implant survival and crestal bone loss in relation to the implant type were considered the main variables and a Friedman test for ordered alternatives was used to assess the difference in crestal bone loss between the different study implants. RESULTS: Twenty-one patients received 83 study implants. Three implants failed within three months and required replacement. The total survival rate was 96.39% after one year and based on 21 patients and 80 implants a mean crestal bone loss of 0.25 mm (SD: 0.38; range: 0-1.48) was measured. After a follow-up of 3, 6, 12, and 21 months no statistically significant differences in crestal bone loss between the different study implants or the different time intervals could be identified. CONCLUSIONS: From this RCT, it is concluded that the implant-abutment connection and a microthreaded external thread configuration have limited influence on crestal bone remodeling. The latter can be considered a multifactorial process and is more dependent on other factors such as biologic considerations than on implant design.