A Study of the Associated Risk Factors for Early Failure and the Effect of Photofunctionalisation in Full-Arch Immediate Loading Treatment Based on the All-on-Four Concept.

Early implant failure occurring within 1 year after implantation has been attributed to various factors. Particularly, early failure can lead to challenges in maintaining a full-arch prosthetic device, necessitating prompt intervention, including reoperation. This study aimed to retrospectively examine implant- and patient-related factors and the effects of photofunctionalisation associated with early failure in patients who underwent treatment using the all-on-four concept in both the maxilla and mandible. We conducted this retrospective study comprising 561 patients with 2364 implants who underwent implant-supported immediate loading with fixed full-arch rehabilitation using the all-on-four concept. We aimed to assess the survival rate within 1 year after implantation and determine the risk factors influencing early failure. The 1-year survival rates after implantation were 97.1% (patient level) and 98.9% (implant level) for the maxilla and 98.5% (patient level) and 99.6% (implant level) for the mandible. There was a significant difference in the implant-level survival rates between the maxilla and mandible, with a lower rate in the maxilla (p = 0.043). The risk factors associated with early implant failure according to the all-on-four concept included the maxilla (implant level) and smoking (patient level). We could not find a significant effect of photofunctionalisation on early failure (p = 0.25) following this treatment protocol.

The All-on-four concept for fixed full-arch rehabilitation of the edentulous maxilla and mandible: a longitudinal study in Japanese patients with 3-17-year follow-up and analysis of risk factors for survival rate.

PURPOSE: Implant-supported immediately loaded fixed full-arch rehabilitation via All-on-four treatment yields good long-term results for both the maxilla and the mandible. However, the risk factors affecting long-term implant survival are unknown, and the long-term prognosis of All-on-four concept procedures in Japanese individuals has not been elucidated. We aimed to determine the cumulative implant survival rate after 3-17-year follow-up and identify the associated risk factors. METHODS: We analysed 561 cases (307 maxillae, 254 mandibles) with 2364 implants (1324 maxillae, 1040 mandibles) that received All-on-four treatment. We investigated the cumulative implant- and patient-level survival rates and various risk factors for implant failure. Statistical analysis was performed using the log-rank test for differences in Kaplan-Meier curves, univariate analysis using the Chi-square test, and multivariate analysis for risk factors affecting the survival rate. RESULTS: The cumulative survival rate was 94.4% by patient level and 97.4% by implant level for the maxilla, and 96.7% by patient level and 98.9% by implant for the mandible, with up to 17 years of follow-up. The maxillary survival rate at the implant level was significantly lower (p < 0.05). Furthermore, the maxillary survival rate within 24 months was significantly lower at the implant level (p < 0.01). Multivariate analysis revealed that the maxilla was the most significant risk factor (p < 0.01). CONCLUSIONS: All-on-four treatment yielded high long-term survival rates in Japanese patients. However, the maxilla showed a significantly lower cumulative survival rate than the mandible, while early failure was significantly higher. Furthermore, the maxilla was a significant risk factor influencing the survival rate.

Dielectric Characterization of Healthy Human Teeth from 0.5 to 18 GHz with an Open-Ended Coaxial Probe.

Dental caries is a major oral health issue which compromises oral health, as it is the main cause of oral pain and tooth loss. Early caries detection is essential for effective clinical intervention. However, methods commonly employed for its diagnosis often fail to detect early caries lesions, which motivates the research for more effective diagnostic solutions. In this work, the relative permittivity of healthy permanent teeth, in caries-prone areas, was studied between 0.5 and 18 GHz. The reliability of such measurements is an important first step to, ultimately, evaluate the feasibility of a microwave device for caries detection. The open-ended coaxial probe technique was employed. Its performance showed to be compromised by the poor probe-tooth contact. We proposed a method based on applying coupling media to reduce this limitation. A decrease in the measured relative permittivity variability was observed when the space between the probe tip and tooth surface was filled by coupling media instead of air. The influence of the experimental conditions in the measurement result was found to be less than 5%. Measurements conducted in ex vivo teeth showed that the relative permittivity of the dental crown and root ranges between 10.0-11.0 and 8.0-9.5, respectively.

A Prognostic Model for the Outcome of Nobel Biocare Dental Implants with Peri-Implant Disease after One Year.

BACKGROUND: This investigation, based on a 1-year retrospective cohort study, aimed to estimate and validate a prognostic model for ailing and failing implants due to peri-implant disease. METHODS: A total of 240 patients (male: 97; female: 143; average age of 57.3 years) with at least one ailing or failing implant were included: 120 patients for model derivation and 120 patients for model validation. The primary outcome measure was the implant status: success, defined as the arrest of the disease, or failure defined as implant extraction, prevalence or re-incidence of peri-implant disease). Potential prognostic risk indicators were collected at the baseline evaluation. The relative risk (RR) was estimated for the predictors through logistic regression and the c-statistic (95% confidence interval) was calculated for both derivation and validation sets. The significance level was set at 5%. RESULTS: The risk model retrieved the prognostic factors age (RR = 1.04), history of Periodontitis (RR = 3.13), severe peri-implant disease status (RR = 3.26), implant length (RR = 3.52), early disease development (RR = 3.99), with good discrimination in both the derivation set (0.763 [0.679; 0.847]) and validation set (0.709 [0.616; 0.803]). CONCLUSIONS: A prognostic risk model for estimating the outcome of implants with peri-implant disease is available, with a good performance considering the c-statistic evaluation.

The All-on-4 concept for full-arch rehabilitation of the edentulous maxillae: A longitudinal study with 5-13 years of follow-up.

BACKGROUND: Full-arch immediate function protocols such as the All-on-4 concept need long-term validation. PURPOSE: To report the 5-13 year outcomes of the All-on-4 treatment concept for the rehabilitation of the edentulous maxilla. MATERIALS AND METHODS: This retrospective case series study involved 1072 patients (4288 maxillary implants) rehabilitated through the All-on-4 treatment concept. Primary outcome measures were cumulative prosthetic and implant success (life table analysis). Secondary outcome measures consisted in marginal bone loss (MBL) at 5 and 10 years, biological and mechanical complications. The estimation of risk indicators was performed through multivariable analysis for the outcome variables implant failure (Cox regression to estimate hazard ratios and 95% confidence intervals [95% CI]), MBL > 2.8 mm at 5 years, MBL > 3.0 mm at 10 years, biological and mechanical complications (binary logistic regression to estimate odds ratios [OR] with 95% CI). RESULTS: Eighteen patients deceased unrelated to the implant treatment (1.7%) and 219 patients (20.4%) were lost to follow-up. The prosthetic success rate was 99.2%; Implant cumulative survival and success rate was 94.7% and 93.9%, respectively, with up to 13 years of follow-up. Male gender (HR = 1.73), smoking (HR = 1.94), and mechanical complications (HR = 0.59) were significantly associated with implant failure. Average MBL at 5 and 10 years was 1.18 mm (95% CI: 1.16, 1.21) and 1.67 mm (95% CI: 1.58, 1.77) with age (OR = 0.97), male gender (OR = 0.58), smoking (OR = 1.73), and biological complications (OR = 2.1) associated with MBL > 2.8 mm at 5 years. The incidence of biological complications was 7.8% at implant level, with age (OR = 0.98) and smoking (OR = 1.53) significantly associated. The incidence of mechanical complications was 58.8% for the provisional prostheses and 7.3% for the definitive prostheses. CONCLUSIONS: The high success rates registered for both implants and prostheses together with the low MBL confirm the All-on-4 treatment concept is predictable and safe in the long term outcome.

The All-on-4 treatment concept for the rehabilitation of the completely edentulous mandible: A longitudinal study with 10 to 18 years of follow-up.

BACKGROUND: There is a need for studies evaluating the long term outcomes of the All-on-4 treatment concept. PURPOSE: To evaluate the long term clinical and radiographic outcomes of the All-on-4 treatment concept in the mandible. MATERIALS AND METHODS: This retrospective longitudinal case series study included 471 patients (women: 286, men: 185, average age = 57.7 years) rehabilitated with 1884 implants in immediate function supporting 471 fixed full-arch mandibular prostheses and followed for 10 to 18 years. Primary outcome measures were prosthetic survival and implant success and survival (estimated using life tables). Secondary outcome measures were marginal bone loss (MBL) at 10 and 15 years, biological and mechanical complications. Multivariable analysis was used to estimate potential risk indicators for implant failure (Cox regression to estimate hazard ratios and 95% confidence intervals (95%CI)), MBL > 3 mm at 10 and 15 years, biological and mechanical complications (binary logistic regression to estimate odds ratios [ORs] with 95%CI). RESULTS: Twenty-seven patients deceased (5.7%) and 149 patients (31.6%) were lost to follow-up. The cumulative prosthetic survival rate was 98.8%; the implant cumulative survival and success rate was 93% and 91.7%, respectively up to 18 years of follow-up. Previous biological complications (HR = 4.43) were significantly associated with implant failure. Average (95% CI) MBL at 10- and 15-years were 1.72 mm (95%CI: 1.59, 1.85) and 2.32 mm (95% CI: 1.98, 2.66). Smoking (OR = 2.72), previous failure of a contiguous implant (OR = 3.89) and biological complication (OR = 8.11) were associated with MBL > 3 mm. The incidence of biological complications was 11.8% at implant level, with previous failure of a contiguous implant (OR = 5.56), smoking (OR = 1.75), and systemic condition (OR = 1.65) were significantly associated. The incidence of mechanical complications was 36.7% with male gender (OR = 1.67) and type of prosthetic material used in the restoration significantly associated (metal-acrylic OR = 0.30; metal-ceramic OR = 0.22)). CONCLUSIONS: Considering the implant, prosthetic and MBL outcomes it is concluded that the All-on-4 is a viable treatment option validated in the long term. Nevertheless, biological and mechanical complications can occur.

Adult Patient Risk Stratification Using a Risk Score for Periodontitis.

BACKGROUND: There is a need for analytical tools predicting the risk of periodontitis. The purpose of this study was to estimate and evaluate a risk score for prediction of periodontitis. MATERIALS AND METHODS: This case-cohort study included a random sample of 155 cases (with periodontitis) and 175 controls (randomly sampled from the study population at baseline) that were followed for 3-year. A logistic regression model was used with estimation of the risk ratio (RR) for each potential predictor. RESULTS: The risk model included the predictors "age > 53 years" (RR = 0.53), "smoking" (RR = 2.9), "gingivitis at baseline" (RR = 3.1), "subgingival calculus at baseline" (RR = 1.9), "history of periodontitis" (RR = 2.3), and "less than 2 observations in the first year of follow-up" (RR = 3.7). Patients were distributed into three risk groups based on the preanalysis risk: low risk, moderate risk, and high risk. The risk score discrimination (95% confidence interval (CI)) was 0.75 (0.70; 0.80) (p < 0.001, C-statistic). CONCLUSIONS: The risk score estimated in the present study enabled to identify patients at higher risk of experiencing periodontitis and may be considered a useful tool for both clinicians and patients.

Risk Score to Predict Dental Caries in Adult Patients for Use in the Clinical Setting.

BACKGROUND: There is a need for risk prediction tools in caries research. This investigation aimed to estimate and evaluate a risk score for prediction of dental caries. MATERIALS AND METHODS: This case-cohort study included a random sample of 177 cases (with dental caries) and 220 controls (randomly sampled from the study population at baseline), followed for 3 years. The risk ratio (RR) for each potential predictor was estimated using a logistic regression model. The level of significance was 5%. RESULTS: The risk model for dental caries included the predictors: "presence of bacterial plaque/calculus" (RR = 4.1), "restorations with more than 5 years" (RR = 2.3), ">8 teeth restored" (RR = 2.0), "history/active periodontitis" (RR = 1.7) and "presence of systemic condition" (RR = 1.4). The risk model discrimination (95% confidence interval) was 0.78 (0.73; 0.82) (p < 0.001, C-statistic). Patients were distributed into three risk groups based on the pre-analysis risk (54%): low risk (

A Peri-Implant Disease Risk Score for Patients with Dental Implants: Validation and the Influence of the Interval between Maintenance Appointments.

BACKGROUND: There is a need for tools that provide prediction of peri-implant disease. The purpose of this study was to validate a risk score for peri-implant disease and to assess the influence of the recall regimen in disease incidence based on a five-year retrospective cohort. METHODS: Three hundred and fifty-three patients with 1238 implants were observed. A risk score was calculated from eight predictors and risk groups were established. Relative risk (RR) was estimated using logistic regression, and the c-statistic was calculated. The effect/impact of the recall regimen (≤ six months; > six months) on the incidence of peri-implant disease was evaluated for a subset of cases and matched controls. The RR and the proportional attributable risk (PAR) were estimated. RESULTS: At baseline, patients fell into the following risk profiles: low-risk (n = 102, 28.9%), moderate-risk (n = 68, 19.3%), high-risk (n = 77, 21.8%), and very high-risk (n = 106, 30%). The incidence of peri-implant disease over five years was 24.1% (n = 85 patients). The RR for the risk groups was 5.52 (c-statistic = 0.858). The RR for a longer recall regimen was 1.06, corresponding to a PAR of 5.87%. CONCLUSIONS: The risk score for estimating peri-implant disease was validated and showed very good performance. Maintenance appointments of < six months or > six months did not influence the incidence of peri-implant disease when considering the matching of cases and controls by risk profile.

Short-term report of an ongoing prospective cohort study evaluating the outcome of full-arch implant-supported fixed hybrid polyetheretherketone-acrylic resin prostheses and the All-on-Four concept.

BACKGROUND: More research is needed on the study of new materials for fixed prosthetic implant-supported rehabilitations. PURPOSE: The purpose of this study was to report the short-term outcome of full-arch implant-supported fixed hybrid polyetheretherketone (PEEK)-acrylic resin prostheses and the all-on-four concept. MATERIALS AND METHODS: This prospective cohort clinical study included 37 patients (29 women, eight men) with an average age of 60 years (range: 38-78 years) with 49 full-arch hybrid PEEK-acrylic resin prosthesis supported by implants through the all-on-four concept. Primary outcome measures were prosthetic survival. RESULTS: Two patients with two maxillary prostheses were lost to follow-up. One patient with a double full-arch rehabilitation fractured the mandibular PEEK framework, rendering a 98% prosthetic survival rate. No implants were lost. The average (SD) marginal bone remodeling after 1 year of follow-up was 0.37 mm (0.58 mm). Technical complications concerning the veneer adhesion occurred in six patients and were resolved in all patients (with exception of the patient with prosthetic failure) through the creation of mechanical retentions and changing the bonding primer. Mechanical complications occurred in three patients and five prostheses consisting in prosthetic screw loosening (n = 2 patients) and fracture of the acrylic resin teeth (the patient with a prosthetic failure). CONCLUSIONS: Within the limitations of this study, the results suggest that hybrid polymer (PEEK)-acrylic resin prostheses supported by implants for full-arch rehabilitation may represent a valid treatment option, still requiring longer-term validation.

Five-year outcome of a retrospective cohort study comparing smokers vs. nonsmokers with full-arch mandibular implant-supported rehabilitation using the All-on-4 concept.

The aim of this study was to compare the 5-year outcome of full-arch mandibular fixed prosthetic rehabilitation using the All-on-4 concept in smoking and nonsmoking patients. This retrospective cohort study included 200 patients (n = 100 smokers, n = 100 nonsmokers), 119 women and 81 men, with an average age of 53.7 years, rehabilitated in immediate function with 800 implants. Implant cumulative survival rate estimation (Kaplan-Meier with log-rank test) and marginal bone resorption (MBR) at 5 years (Mann-Whitney test) were compared between both groups. Multivariable analysis was used to investigate potential risk indicators for MBR ≥ 2.8 mm at 5 years. Nine patients (4.5%) were lost to follow-up. Four patients lost eight implants, specifically one nonsmoking patient (n = 1 implant) and three smoking patients (n = 7 implants), resulting in a cumulative survival rate estimation of 99.0% and 96.9% for nonsmokers and smokers, respectively (P = 0.296). The average (standard deviation) MBR at 5 years was 1.68 mm (0.76 mm) and 1.98 mm (1.02 mm) for nonsmokers and smokers, respectively (P = 0.045). Smoking (odds ratio = 2.92) was the only risk indicator significantly associated with MBR ≥ 2.8 mm in multivariable analysis. Smoking should not be an absolute contraindication for rehabilitation of the edentulous mandible through the All-on-4 concept; however, smoking habits were significantly associated with MBR ≥ 2.8 mm.

Risk Factors for Implant Failure and Peri-Implant Pathology in Systemic Compromised Patients.

PURPOSE: To identify the possible risk factors for implant failure and peri-implant pathology in a population of systemically compromised patients. MATERIALS AND METHODS: This retrospective clinical study included a total of 721 systemically compromised patients (422 women, 299 men), with an average age of 51 years (range: 20 to 87) rehabilitated with dental implants. The average follow-up time was 7.3 years. The patients' demographic variables (age and gender) and clinical variables (implant location, type of implant surface, and systemic conditions) were recorded. Outcome measures were implant failure and peri-implant pathology. Binary logistic regression models were performed to investigate the effect of the patients' demographic and clinical characteristics on the dependent variables implant failure and peri-implant pathology. A linear regression model was performed to correlate the patient's characteristics with the number of failed implants. Odds ratios (OR) with 95% confidence intervals and corresponding levels of significance were estimated for each variable. RESULTS: Multivariate logistic regression disclosed increased age (patients over 40 years of age) as a risk factor for implant failure (OR = 2.63) and hepatitis as a risk factor for peri-implant pathology (OR = 3.74). Multivariate linear regression disclosed rheumatologic and cardiac diseases to be correlated with a higher number of failed implants. CONCLUSIONS: Within the limitations of this study, the results suggest no absolute contraindications for implant rehabilitation in a population of systemically compromised patients. Nevertheless, this study suggests that increasing age, rheumatological condition, cardiovascular condition, and hepatitis should be considered when performing implant-supported rehabilitations due to their negative influence on the outcome.

Retrospective cohort clinical investigation of a dental implant with a narrow diameter and short length for the partial rehabilitation of extremely atrophic jaws.

We investigated the short-term clinical outcomes of narrow-diameter short-length implants for the fixed-prosthetic partial rehabilitation of extremely resorbed jaws. Twenty-three patients requiring partial rehabilitations with narrow-platform short-length implants in any jaw were included in this study. In total, 30 implants 3.3 mm in diameter and 7 (n = 15 implants) or 8.5 (n = 15 implants) mm in length were inserted. The primary outcome measure was implant cumulative survival rate (CSR); the secondary outcome measures were marginal bone resorption at 1 and 3 years and the incidence of biologic and mechanical complications. Five patients (21.7%) with six implants (20%) were lost to follow-up. Two implants failed in two patients, yielding a CSR at 3 years of follow-up of 93.4%. The average (standard deviation) marginal bone resorption was 1.34 mm (0.95 mm) after the first year and 1.38 mm (0.78 mm) after the third year. Biologic complications occurred in three patients; mechanical complications occurred in three patients. Despite the limitations of the study, our findings show that the use of new narrow-diameter short-length implants for the rehabilitation of extremely atrophic regions is viable in the short-term, and can be considered a treatment alternative in extremely resorbed jaws.

Comparison of marginal bone loss and implant success between axial and tilted implants in maxillary All-on-4 treatment concept rehabilitations after 5 years of follow-up.

BACKGROUND: There is need for more scientific and clinical information on longer-term outcomes of tilted implants compared to implants inserted in an axial position. PURPOSE: Comparison of marginal bone loss and implant success after a 5-year follow-up between axial and tilted implants inserted for full-arch maxillary rehabilitation. MATERIAL AND METHODS: The retrospective clinical study included 891 patients with 3564 maxillary implants rehabilitated according to the All-on-4 treatment concept. The follow-up time was 5 years. Linear mixed-effect models were performed to analyze the influence of implant orientation (axial/tilted) on marginal bone loss and binary logistic regression to assess the effect of patient characteristics on occurrence of marginal bone loss >2.8 mm. Only those patients with measurements of at least one axial and one tilted implant available were analyzed. This resulted in a data set of 2379 implants (1201 axial, 1178 tilted) in 626 patients (=reduced data set). RESULTS: Axial and tilted implants showed comparable mean marginal bone losses of 1.14 ± 0.71 and 1.19 ± 0.82 mm, respectively. Mixed model analysis indicated that marginal bone loss levels at 5 years follow up was not significantly affected by the orientation (axial/tilted) of the implants in the maxillary bone. Smoking and female gender were associated with marginal bone loss >2.8 mm in a logistic regression analysis. Five-year implant success rates were 96%. The occurrence of implant failure showed to be statistically independent from orientation. CONCLUSIONS: Within the limitations of this study and considering a follow-up time of 5 years, it can be concluded that tilted implants behave similarly with regards to marginal bone loss and implant success in comparison to axial implants in full-arch rehabilitation of the maxilla. Longer-term outcomes (10 years +) are needed to verify this result.

Prevalence of periodontitis, dental caries, and peri-implant pathology and their relation with systemic status and smoking habits: Results of an open-cohort study with 22009 patients in a private rehabilitation center.

OBJECTIVES: This investigation, based on a 3-year epidemiological surveillance open cohort study, aimed to provide an insight of the prevalence of periodontitis, dental caries and peri-implant pathology and to compare inferentially between healthy and systemic compromised patients. METHODS: A total of 22009 patients were observed consisting in 9035 men (41.1%) and 12974 women (58.9%) with an average age of 48.5 years (standard deviation of 15.6years). The prevalence of the 3 chronical oral diseases was calculated. The comparison between healthy and systemic compromised patients for each oral disease was performed through multivariate logistic regression: Odds ratios (OR) with 95% confidence intervals (95%CI) were estimated in one general model and one systemic condition specific model adjusted for age and gender. Attributable fractions were estimated for systemic conditions (both models). The level of significance was set at 5%. RESULTS: The prevalence rate of periodontitis, dental caries and peri-implant pathology was 17.6%, 36.6% and 13.9%, respectively. The systemic compromised status was associated with the prevalence of the three chronical oral diseases on the general models. The systemic condition specific models yielded Diabetes [OR=1.49, 95%CI (1.24;1.79)] and HIV+ [OR=4.37, 95%CI (1.05;18.24)] as risk indicators for Periodontitis; cardiovascular conditions [OR=1.10, 95%CI (1.01;1.20)], Diabetes [OR=1.24, 95%CI (1.05;1.46)] and neurologic conditions [OR=1.84, 95%CI (1.32;2.57)] as risk indicators for dental caries; and smoking habits as a risk indicator for all three oral diseases [OR=1.90, 95%CI (1.74;2.07) for Periodontitis; OR=1.18, 95%CI (1.09;1.27) for dental caries; OR=1.84, 95%CI (1.64;2.07) for peri-implant pathology]. Attributable fractions estimated a potential reduction of 12.2% of Periodontitis, and 4.3% of dental caries cases if the exposure to systemic conditions was prevented; while the prevention of exposure to smoking alone would result in a potential reduction of 37%, 7%, and 39% of Periodontitis, dental caries, and peri-implant pathology cases, respectively. CLINICAL SIGNIFICANCE: The present study describes an epidemiological approach to the distribution and determinants of the three principal chronical oral diseases. The association of systemic conditions and smoking habits with oral disease prevalence highlight the importance of a narrow monitoring system. CONCLUSIONS: The present study reported a high prevalence for oral disease and a potential association of a systemic compromised status and smoking habits with the three chronical oral diseases.

Outcomes of Immediate Function Implant Prosthetic Restorations with Mechanical Complications: A Retrospective Clinical Study with 5 Years of Follow-Up.

Mechanical complications may have a significant impact on the outcome of implant-supported restorations; however, few studies address the topic. This study investigated the outcomes of implant supported restorations with mechanical complications. A total of 378 patients with 378 restorations supported by 1283 implants were included. Results demonstrated a prosthetic and implant cumulative survival rate at 5 years of 99.7% and 95.7%, respectively. Maxillary implants were a determinant for implant failure (hazard ratio= 6.7), while a reduced risk was registered for single tooth restorations (hazard ratio= 0.1) after adjusting for other variables of interest.

Seven mm long dental implants in posterior jaws: 3-year report of an ongoing prospective single cohort study.

PURPOSE: To report on the outcome of 7 mm long implants in the rehabilitation of posterior areas of atrophic jaws 3 years after loading. MATERIALS AND METHODS: This prospective study included 127 patients treated with 217 implants supporting 165 fixed prostheses. Final abutments were delivered at surgery stage and in the large majority of patients (n = 116) the implants (n = 199) were loaded after 4 months. Primary outcome measures were implant success and prosthetic success calculated at patient level; secondary outcome measures were complications, and marginal bone level changes calculated at patient level. RESULTS: Thirteen patients with 21 implants dropped out of the study after 3 years. Implant losses occurred in 10 of the 127 patients and 14 of the 217 implants placed failed, giving a cumulative success rate of 93.7% at 3 years, using the patient as unit of analysis. Eight prosthetic failures occurred in six patients, rendering a prosthetic success rate 95.3% at patient level. The average (standard deviation) marginal bone resorption after 3 years of follow-up was 1.46 mm (0.78 mm). Complications occurred in 13 patients (10.2%) and 15 implants (6.9%). CONCLUSIONS: Within the limitations of this study, 7 mm long implants in posterior atrophic jaws can be a viable treatment option given the good prosthetic and implant success rates, low marginal bone loss and low incidence of complications. Nevertheless, longer follow-ups are needed to validate the long-term outcome. Conflict-of-interest statement: This study was funded by grant no. 2015-1378 from Nobel Biocare Services. Paulo Maló is currently a consultant for Nobel Biocare. The remaining authors declare no conflicts of interest.

Attributable fractions, modifiable risk factors and risk stratification using a risk score for peri-implant pathology.

PURPOSE: This study aimed to estimate the impact of risk factors for peri-implant pathology, to identify potentially modifiable factors, and to evaluate the accuracy of the risk algorithm, risk scores and risk stratification. METHODS: This retrospective case-control study with 1275 patients (255 cases; 1020 controls) retrieved a model according to the predictors: history of Periodontitis, bacterial plaque, bleeding, bone level, lack of passive fit or non-optimal screw joint, metal-ceramic restoration, proximity to other implants/teeth, and smoking habits. Outcome measures were the attributable fraction; the positive and negative likelihood ratios at different disease cut-off points illustrated by the area under the curve statistic. RESULTS: Six predictors may be modified or controlled directly by either the patient or the clinician, accounting for a reduction in up to 95% of the peri-implant pathology cases. The positive and negative likelihood ratios were 9.69 and 0.13, respectively; the area under the curve was 0.96; a risk score was developed, making the complex statistical model useful to clinicians. CONCLUSIONS: Based on the results, six predictors for the incidence of peri-implant pathology can be modified to significantly improve the outcome. It was possible to stratify patients per risk category according to the risk score, providing a tool for clinicians to support their decision-making process.

The NobelGuide® All-on-4® Treatment Concept for Rehabilitation of Edentulous Jaws: A Retrospective Report on the 7-Years Clinical and 5-Years Radiographic Outcomes.

BACKGROUND: There is a necessity of studies documenting the long-term outcome of full-arch flapless rehabilitations. PURPOSE: To evaluate the 7 years implant and prosthesis survival rate and 5-years marginal bone loss of full-arch fixed prosthetic rehabilitations supported by implants in immediate function with the All-on-4® treatment concept using a computer guided surgical protocol (NobelGuide® , Nobel Biocare). MATERIALS AND METHODS: This retrospective clinical study included 111 edentulous patients (n = 53 bruxers; n = 21 smokers; n = 59 systemically compromised), rehabilitated between February 2005 and November 2010 with 532 implants with the All-on-4® treatment concept using NobelGuide® . Outcome measures were implant and prosthesis survival, marginal bone loss at 5-years and the incidence of mechanical and biological complications. Survival was calculated using life-table analysis. Inferential analysis was performed to compare the difference in marginal bone loss between axial and tilted implants. RESULTS: Sixteen patients were lost to follow-up. The implant cumulative survival rate was 94.5% at 7 years. Prosthetic survival was 97.8% (n = 3 prosthetic failures). The average (standard deviation) marginal bone loss at 5 years was 1.3 mm (1.06 mm) overall, 1.27 mm (1.02 mm) for tilted implants and 1.34 mm (1.1 mm) for axial implants (p < .001). Ninety-one patients experienced complications in the provisional prostheses (n = 47 patients who were bruxers; n = 25 patients with implant-supported rehabilitation as opposing dentition) ranging from prosthetic fracture (n = 66 patients) to abutment or prosthetic screw loosening (n = 74 patients). Thirty-three patients experienced complications in the definitive prostheses (all exclusive to patients who were bruxers or had implant-supported rehabilitations as opposing dentition) ranging from acrylic-resin prosthetic/crown fracture (n = 23 patients) to abutment or prosthetic screw loosening (n = 10 patients). Twenty-five patients (22%) registered peri-implant pathology. CONCLUSIONS: Within the limitations of this study, it is possible to conclude that this treatment modality for completely edentulous jaws is possible with high long-term survival outcomes. Bruxing and smoking habits had a negative impact on implant failure, mechanical, and biological complications.

The Influence of Crown-to-Implant Ratio on Short Implant Marginal Bone Loss.

PURPOSE: There is a need for more studies evaluating the marginal bone loss (MBL) of rehabilitations in the posterior regions of extremely resorbed maxillae and mandibles supported by short-length dental implants with a high crown/implant ratio (C/I-R). The aim of this study was to evaluate the influence of the C/I-R in implants on MBL considering dental implants with 4 mm of width and 7 mm of length. MATERIALS AND METHODS: This retrospective cohort study included 59 patients (mean age of 52.8 years) rehabilitated with at least one implant 4 mm in width and 7 mm in length, with an anodically oxidized surface and external connection on the premolar or molar positions, supporting a fixed prosthesis, and in function for a period of 36 months. Periapical radiographs at 36 months were used to calculate the C/I-R and MBL. The Spearman correlation coefficient was used to test the correlation between C/I-R and MBL. The level of significance was set at 5%. RESULTS: One hundred eighteen implants from 59 patients were evaluated. The mean ± SD MBL was 0.67 ± 0.63 mm. The C/I-R mean ± SD was 2.53 ± 0.79 mm. Thirty implants presented a C/I-R ≤ 2, while 88 implants had a C/I-R > 2. A weak nonsignificant inverse correlation (r = -0.081; P = .383, Spearman) was registered between C/I-R and MBL. CONCLUSION: Within the limitations of this study, it is possible to conclude that implant-supported fixed prostheses with C/I-R > 2 do not correlate positively with MBL.