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 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.

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 (<half the pre-analysis risk; caries incidence = 6.8%), moderate risk (half-to-less than the pre-analysis risk; caries incidence = 20.4%) and high risk (≥the pre-analysis risk; caries incidence = 27%). Conclusions: The present study estimated a simple risk score for prediction of dental caries retrieved from a risk algorithm with good discrimination.

Immediate function dental implants inserted with less than 30N·cm of torque in full-arch maxillary rehabilitations using the All-on-4 concept: retrospective study

The aim of this retrospective clinical study was to evaluate the short-term implant success rate and marginal bone loss in full-arch fixed prosthetic maxillary rehabilitations supported by implants in immediate function with the All-on-4 treatment concept placed with insertion torque of <30N·cm or ≥30N·cm. This study included 83 patients (69 female, 14 male) with 332 implants placed (120 inserted with <30N·cm and 212 inserted with ≥30N·cm) who were treated between January 2010 and March 2013. Outcome measures were implant success and marginal bone loss at 1year of follow-up. Ten patients (12.0%; 13 implants inserted with <30N·cm and 27 implants with ≥30N·cm) were lost to follow-up. The cumulative implant success rate was 97.5% at the patient level, and 98.3% for implants inserted with <30N·cm and 97.5% for implants inserted with ≥30N·cm. The mean±standard deviation marginal bone loss at 1year was 1.14±0.38mm for implants inserted with <30N·cm and 1.39±0.49mm for implants inserted with ≥30N·cm (significant difference; P<0.001, Wilcoxon signed rank test). These results indicate that implants with insertion torques of <30N·cm may render comparable success rates and marginal bone loss at 1year compared to implants inserted with insertion torques of ≥30N·cm.

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.

Immediate full-arch rehabilitation of the severely atrophic maxilla supported by zygomatic implants: a prospective clinical study with minimum follow-up of 6 years

The aim of this study was to evaluate the outcomes of immediate full-arch prostheses supported by zygomatic implants alone or in combination with standard fixtures after a minimum of 6 years of loading. From October 2008 to April 2010, 15 patients with severely atrophic maxillae were treated using four zygomatic implants or two zygomatic implants in conjunction with two conventional fixtures. All subjects received a fixed screw-retained prosthesis within 3hours of surgery, while the final restoration was delivered after 6 months. Follow-up examinations were scheduled to evaluate zygomatic implant survival, conventional dental implant success, prosthetic success, plaque and bleeding scores, marginal bone loss for conventional dental implants, and patient satisfaction. Forty-two zygomatic fixtures and 18 standard implants were placed. Patients were followed up for a minimum of 79 months (range 79-97 months, average 90.61 months). No implant was lost, leading to implant and prosthetic survival rates of 100%. Bone loss for conventional implants averaged 1.39±0.10mm after 6 years of function, leading to a 100% implant success rate. High levels of patient satisfaction were recorded. These medium-term results indicate that immediate full-arch rehabilitation supported by zygomatic implants could be considered a viable treatment modality for the severely atrophic maxilla.

Partial Rehabilitation with Distally Tilted and Straight Implants in the Posterior Maxilla with Immediate Loading Protocol: A Retrospective Cohort Study with 5-Year Follow-up

PURPOSE

The purpose of this study was to compare the outcome of fixed partial prostheses in the posterior maxilla with two axially placed implants or one implant placed distally tilted and one axially placed implant following an immediate loading protocol.

MATERIALS AND METHODS

A sample of 60 patients was divided into two groups-group 1: 30 patients rehabilitated with one axially placed implant and one implant placed distally tilted in the posterior maxilla; group 2: 30 patients rehabilitated with two axially placed implants in the posterior maxilla. Outcome measures were implant survival based on function, marginal bone resorption, and the incidence of mechanical and biologic complications at 5 years; inferential statistics were used to analyze the intergroup and intragroup differences. The level of significance was set at 5%.

RESULTS

No significant differences were found between both groups in survival, complications, or marginal bone resorption. One axially placed implant was lost at 58 months in group 1, rendering a cumulative survival estimate at 5 years of 96.7% and 98.3% in group 1 and the total sample, respectively (P = .317). Mechanical complications occurred in 16 patients (26.7%; n = 8 patients in each group; [P > .999]), consisting of fractures in the provisional prosthesis (n = 8 patients), chipped ceramics of the definitive prosthesis (n = 2 patients), loosening of prosthetic components (n = 5 patients), and fracture of an attachment screw (n = 1 patient). Biologic complications occurred in 5 patients (8.3%; group 1 = 4 patients; group 2 = 1 patient; [P = .161]), consisting of peri-implant pathology. The mean ± SD marginal bone loss was 2.02 ± 0.36 mm and 1.90 ± 0.69 mm for groups 1 and 2, respectively (P = .235). In group 1, the mean ± SD marginal bone loss was 1.92 ± 0.48 mm and 2.11 ± 0.44 mm for the implant placed distally tilted and axially placed implant, respectively; the difference was significant (P < .001).

CONCLUSION

Within the limitations of this study, the use of implants placed distally tilted together with axially placed implants or two axially placed implants in the fixed partial rehabilitation of the posterior maxilla are viable treatment alternatives.

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.

Complete Edentulous Rehabilitation Using an Immediate Function Protocol and an Implant Design Featuring a Straight Body, Anodically Oxidized Surface, and Narrow Tip with Engaging Threads Extending to the Apex of the Implant: A 5-year Retrospective Clinical Study

PURPOSE

To report the 5-year outcome of NobelSpeedy design implants in immediate function fixed prosthetic rehabilitations.

MATERIALS AND METHODS

This retrospective clinical study included 46 consecutive patients (29 women and 17 men) with an average age of 55 years (range, 32 to 78 years) who were rehabilitated between 2003 and 2004 with full-arch restorations supported by dental implants in immediate function. The primary outcome measures were implant survival calculated based on implant function and using life tables. The secondary outcome measures were marginal bone levels measured at 3 and 5 years, and the incidence of mechanical and biologic complications.

RESULTS

Five patients with 21 study implants dropped out (11%). One-hundred eighty-nine implants were inserted in the maxilla (n = 166) and mandible (n = 23). Five patients lost five implants, giving a cumulative survival rate of 97.3% at 5 years of follow-up. The average (SD) marginal bone levels were 1.45 mm (0.83 mm) and 1.72 mm (1.04 mm) at 5 years of follow-up. The incidence of mechanical complications in the provisional and definitive prostheses was registered in 14 and 6 patients, respectively: prosthetic screw loosening (n = 4 provisional prostheses, n = 3 definitive prostheses), abutment screw loosening (n = 5 provisional prostheses), fracture of the acrylic resin prostheses (n = 5 provisional prostheses, n = 1 definitive prosthesis), chipping of a ceramic crown (n = 1 definitive prosthesis), and fracture of a ceramic crown (n = 1 definitive prosthesis). The incidence of biologic complications (peri-implant pathology) was registered in 6 patients and 12 implants (7.1%).

CONCLUSION

Within the limitations of this study, it is possible to conclude that implants of the NobelSpeedy type used in immediate function for support of fixed prosthetic full-arch rehabilitations are a valid option, with a high survival rate.

Outcome of dental implants in diabetic patients with and without cardiovascular disease: A 5-year post-loading retrospective study

PURPOSE

To investigate the outcome of immediate function of dental implant rehabilitations in diabetic patients with and without coexisting cardiovascular diseases (CVD).

MATERIALS AND METHODS

This retrospective study included 70 diabetic patients (33 females and 37 males, average age: 59 years old), rehabilitated with 352 implants and divided into two groups (CVD: 38 patients; non-CVD: 32 patients). Diabetes mellitus was defined as fasting plasma glucose ≥ 7.0 mmol/l (126 mg/dl) or 2 h plasma glucose ≥ 11.1mmol/l (200 mg/dl). The data was retrieved from patient records. Primary outcome measures were prosthesis and implant survival; secondary outcome measures were marginal bone loss and complications (biological or mechanical). The follow-up was 5 years after loading for all patients.

RESULTS

Seven patients (10%) were lost to follow-up (one patient in the CVD group; and six patients in the non-CVD group). One prosthesis failed in the non-CVD group, rendering a 97.4% survival rate, compared to 100% in the CVD group (non-significant difference between groups; P = 0.359). Ten implants failed in 7 patients: CVD group with eight implant failures in 5 patients (86.7% cumulative survival rate) versus two implants in 2 patients in the non-CVD group (93.8% cumulative survival rate) with a non-significant difference between both groups (P = 0.365). The average (95% confidence interval) marginal bone loss at 1- and 5-years was 0.95 mm (0.66 mm; 1.23 mm) and 1.52 mm (1.20 mm; 1.88 mm), respectively in the CVD group; and 0.78 mm (0.40 mm; 1.16 mm) and 1.54 mm (0.86 mm; 2.31 mm), respectively for the non-CVD group; with no significant differences between groups at 1 year (P = 0.979) and 5 years (P = 0.300). Complications occurred in 38 patients (CVD group: 21 patients; non-CVD group: 16 patients); with a non-significant difference between both groups (P = 0.660).

CONCLUSIONS

Implant rehabilitations represent a valid treatment for diabetic patients with or without coexisting CVD, with a good risk/benefit ratio.

Three-Year Outcome of Fixed Partial Rehabilitations Supported by Implants Inserted with Flap or Flapless Surgical Techniques

PURPOSE

The aim of this prospective clinical study was to evaluate the 3-year outcome of fixed partial prostheses supported by implants with immediate provisionalization without occlusal contacts inserted in predominantly soft bone with flap and flapless protocols.

MATERIALS AND METHODS

Forty-one patients partially rehabilitated with 72 NobelSpeedy implants (51 maxillary; 21 mandibular) were consecutively included and treated with a flapless surgical protocol (n = 20 patients; 32 implants) and flapped surgical protocol (n = 21 patients; 40 implants). Primary outcome measure was implant survival; secondary outcome measures were marginal bone resorption (comparing the bone levels at 1 and 3 years with baseline) and the incidence of biological, mechanical, and esthetic complications. Survival was computed through life tables; descriptive statistics were applied to the remaining variables of interest.

RESULTS

Eight patients with eight implants dropped out of the study. One implant failed in one patient (flapless group) giving an overall cumulative survival rate (CSR) of 98.6%. No failures were noted with the flapped protocol (CSR 100%), while for the implants placed with the flapless surgical technique, a 96.9% CSR was registered. The overall average marginal bone resorption at 3 years was 1.37 mm (SD = 0.94 mm), with 1.14 mm (SD = 0.49 mm) and 1.60 mm (SD = 1.22 mm) for the flap and flapless groups, respectively. Mechanical complications occurred in nine patients (n = 5 patients in the flapless group; n = 4 patients in the flap group). Implant infection was registered in three implants and three patients (flapless group), who exhibited inadequate oral hygiene levels.

CONCLUSIONS

Partial edentulism rehabilitation through immediate provisionalization fixed prosthesis supported by dental implants inserted through flap or flapless surgical techniques in areas of predominantly soft bone was viable at 3 years of follow-up. The limitations and risks of the "free-hand" method in flapless surgery should be considered when planning implant-supported fixed prosthetic reconstructions.

Immediate loading short implants inserted on low bone quantity for the rehabilitation of the edentulous maxilla using an All-on-4 design

More studies evaluating the outcome of short-length dental implants in immediate loading are needed. To evaluate the use of short-length tapered implants in immediate loading for complete edentulous maxillae rehabilitations using an All-on-4 design. This retrospective clinical study included a cohort of 43 patients with 172 implants (74 short-length implants) inserted in low bone quantity. The patients were followed between 4 months and 6 years (average = 3 years). Outcome measures were implant survival, marginal bone remodelling, biological and mechanical complications. Two patients with four short-length implants were lost to follow-up during the first year. Three short and three long implants failed in four patients, rendering an overall cumulative survival rate implant and patient level, respectively, of 95.7% and 95.1% for short implants, 100% for regular implants and 96.6% and 95.2% for long implants. The average marginal bone remodelling at 1 and 3 years was 0.97 and 1.25 mm for the short implants, 0.82 and 0.87 mm for regular implants and 0.87 and 0.98 mm for long implants. Three patients presented 4 short-length implants with peri-implant pockets (3 implants in 2 patients were pseudo-pockets). Mechanical complications were registered in 13 patients (7 provisional prostheses fractures and 6 abutment screw loosening). All complications were treated successfully. Within the limitations of this clinical study, the short-term outcome of fixed prosthetic complete edentulous maxillae rehabilitations supported by short-length implants inserted in low bone quantity areas is viable. Long-term clinical studies are necessary for evaluating the outcome of these implants.

Posterior maxillary implants inserted with bicortical anchorage and placed in immediate function for partial or complete edentulous rehabilitations. A retrospective clinical study with a median follow-up of 7 years

PURPOSE

The aim of this study was to report the outcome of posterior maxillary implants inserted with "bicortical anchorage" in medium or low-density bone and placed in immediate function for the rehabilitation of patients with partial or complete edentulism.

METHODS

Eighty-eight patients (32 males and 56 females, mean age = 54 years; range 28-78 years) were included from October 1999 to November 2008, and followed between 6 months and 13 years (median of 7 years). A total of 124 posterior maxillary implants were inserted with bicortical anchorage (engaging the cortical plates of the maxillary crest along with that of either the sinus or nasal cavities) as follows: MkII (n = 1), MkIII (n = 6), MkIV (n = 18), and NobelSpeedy Groovy (n = 99); (Nobel Biocare AB). Implants were evaluated on the basis of survival, marginal bone levels, and complications (mechanical and biological).

RESULTS

Eleven patients dropped out of the study (12.5 %). Four implants were lost in four patients who underwent complete edentulous rehabilitations, yielding a cumulative survival rate of 94.2 % after a median follow-up of 7 years. The survival rate for the prostheses was 100 %. The marginal bone levels were on average 1.56 mm (standard deviation of 0.87 mm), after 5-years of follow-up. Biological complications occurred with 17 implants in 17 patients. Mechanical complications occurred in 49/88 patients. Thirty of these 49 patients were heavy bruxers.

CONCLUSIONS

Within the limitations of this study, fixed prosthetic rehabilitations for partial and complete edentulism supported by implants in the posterior maxilla which are inserted with bicortical anchorage and placed in immediate function is a viable concept on long-term follow-up. Nevertheless, controlling the occlusion is mandatory in order to decrease the likelihood of mechanical complications.

All-on-4® Treatment Concept for the Rehabilitation of the Completely Edentulous Mandible: A 7-Year Clinical and 5-Year Radiographic Retrospective Case Series with Risk Assessment for Implant Failure and Marginal Bone Level

BACKGROUND

Studies are needed to evaluate long-term outcomes of the All-on-4® treatment concept (Nobel Biocare AB) for rehabilitation of edentulous mandibles by assessing marginal bone levels and risk indicators for implant failure.

PURPOSE

To evaluate 7-year clinical outcomes and 5-year radiographic outcomes of the All-on-4 treatment concept.

MATERIALS AND METHODS

This retrospective case series included patients admitted for implant rehabilitations in the mandible, who were followed for 7 years clinically and 5 years radiographically. Primary outcome measures were cumulative prosthetic and implant survival using patient as the unit of analysis (Kaplan-Meier product limit estimator). Secondary outcome measure was marginal bone level (MBL) at 5 years. Variables associated with implant failure were analyzed using the Cox proportional hazards regression model to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). Binary logistic regression was used to compute odds ratio (OR) with 95% CIs for variables associated with MBL ≥2.8 mm at 5 years.

RESULTS

A total of 324 patients (194 women, 130 men, average age = 58.9 years) were rehabilitated with 1,296 implants supporting 324 full-arch fixed immediately loaded mandibular prostheses. Sixty-four patients (19.8%) were lost to follow-up. Prosthetic survival was 323/324 (99.7%), and 14 patients lost 18 implants, with an estimated cumulative survival rate of 95.4% at 7 years. Variables associated with implant failure were smoking (HR = 5.28; 95% CI: 1.33, 20.91]) and the learning curve effect (0.69 < HR < 0.33 for more experienced levels). Mean MBL at 5 years was 1.81 mm (95% CI: 1.70, 1.92), and smoking was associated with MBL ≥2.8 mm (OR = 2.4; 95% CI: 1.02, 5.62).

CONCLUSIONS

The high implant and prosthetic survival rates and excellent MBL outcome confirm the predictability and safety of the All-on-4 treatment concept over a longer term than previously reported.

Double Full-Arch Versus Single Full-Arch, Four Implant-Supported Rehabilitations: A Retrospective, 5-Year Cohort Study

PURPOSE

To report the 5-year outcome of the All-on-4 treatment concept comparing double full-arch (G1) and single-arch (G2) groups.

MATERIALS AND METHODS

This retrospective cohort study included 110 patients (68 women and 42 men, average age of 55.5 years) with 440 NobelSpeedy groovy implants. One hundred sixty-five full-arch, fixed, immediately loaded prostheses in both jaws were followed for 5 years. G1 consisted of 55 patients with double-arch rehabilitations occluded with implant-supported fixed prostheses, and G2 consisted of 55 patients with maxillary single-arch rehabilitations or mandibular single-arch rehabilitations occluded with natural teeth or removable prostheses. The groups were matched for age (±6 years) and gender. Primary outcome measures were cumulative prosthetic (both interim and definitive) and implant survival (Kaplan-Meier product limit estimator). Secondary outcome measures were marginal bone levels at 5 years (through periapical radiographs and using the patient as unit of analysis) and the incidence of mechanical and biological complications. Differences in survival curves (log-rank test), marginal bone level (Mann-Whitney U test), and complications (chi-square test) were compared inferentially between the two groups using the patient as unit of analysis with significance level set at p ≤ 0.05.

RESULTS

No dropouts occurred. Prosthetic survival was 100%. Five patients lost 5 implants (G1: n = 3; G2: n = 2) before 1 year, rendering an estimated cumulative survival rate of 95.5% (G1: 94.5%; G2: 96.4%; Kaplan-Meier, p = 0.645, nonsignificant). The average (SD) marginal bone level was 1.56 mm (0.89) at 5 years [G1: 1.45 mm (0.77); G2: 1.67 mm (0.99); p = 0.414]. The incidence rate of mechanical complications (in both interim and definitive prostheses) was 0.16 and 0.13 for G1 and G2, respectively (p = 0.032). The incidence rate of biological complications was 0.06 and 0.05 for G1 and G2, respectively (p = 0.669).

CONCLUSIONS

Based on the results, rehabilitating double- or single-arch edentulous patients did not yield significant differences on survival curves. The incidence of mechanical complications was significantly higher for double-arch rehabilitated patients but nevertheless, these mechanical complications did not affect the long-term survival of either the prostheses or the implants.

The NobelGuide® All-on-4® Treatment Concept for Rehabilitation of Edentulous Jaws: A Prospective Report on Medium- and Long-Term Outcomes

BACKGROUND

There is a need for long-term studies on complete edentulous flapless rehabilitations.

PURPOSE

This study aimed to evaluate the long-term outcomes of the rehabilitation of completely edentulous jaws for immediate function with the All-on-4® treatment concept using a computer-guided surgical protocol (NobelGuide®, Nobel Biocare, Göteborg, Sweden).

MATERIALS AND METHODS

This prospective clinical study included 23 totally edentulous patients rehabilitated between February 2005 and May 2006 with 92 implants with the All-on-4 treatment concept using NobelGuide. Outcome measures were implant survival, marginal bone loss at 1, 3, and 5 years, and the incidence of mechanical and biological complications. Survival was calculated using life-table analysis.

RESULTS

Two dropouts occurred. The cumulative implant survival rate was 96.6% at 5 years of follow-up. Prosthetic survival was 100%. The average marginal bone loss was 1.7 mm (standard deviation 1.4 mm) at 1 year, 1.7 mm (standard deviation 0.9 mm) at 3 years, and 1.9 mm (standard deviation 1.1 mm) at 5 years. Seven patients experienced fracture of the definitive prosthesis (6 patients were heavy bruxers), and abutment screw loosening occurred in 2 patients. Two implants in 2 patients showed peri-implant pathology.

CONCLUSIONS

Within the limitations of this study, it is possible to conclude that this treatment modality for completely edentulous jaws is safe and predictable with good long-term outcomes.

Clinical outcomes in the presence and absence of keratinized mucosa in mandibular guided implant surgeries: a pilot study with a proposal for the modification of the technique

OBJECTIVE

To test the hypothesis of the outcome of complete arch flapless guided implant surgery mandibular rehabilitations in the presence or absence of a residual band of keratinized mucosa (KM) < 6 mm wide in the vestibular-lingual aspect, with and without a modification of the surgical protocol.

METHOD AND MATERIALS

Thirty-nine patients were included in this study (12 men and 27 women), with a mean age of 62.5 years (range, 42 to 79 years), divided into 3 groups of 13 patients according to the status of residual band of KM: group 1, KM < 6 mm rehabilitated through a modified guided surgical protocol with flap opening to preserve KM; group 2, KM ≥ 6 mm; and group 3, KM < 6 mm; patients from both groups 2 and 3 were rehabilitated through flapless guided implant surgery without modification of the protocol. Group 2 and 3 patients were age- and sex-matched with group 1. Outcome measures were clinical attachment loss (CAL) ≥ 2 mm after 1 year (backward conditional regression), incidence of dehiscences, dental plaque, bleeding, and implant infections. The level of significance chosen was 5%.

RESULTS

Thirty-nine patients with 156 implants were followed for 1 year, and no dropouts occurred. Absence of a residual band of KM ≥ 6 mm in the vestibular-lingual aspect was significantly associated with CAL (odds ratio, 39.1; P = .036) and dehiscences (P = .003).

CONCLUSION

Within the limitations of this study, the absence of a residual band of KM ≥ 6 mm wide in the vestibular-lingual aspect in patients rehabilitated in the complete edentulous mandible with flapless guided implant surgery may be associated with CAL and a higher incidence of dehiscences after 1 year of follow-up. This possible association needs to be confirmed in studies with stronger designs and longer follow-ups.

Five-year outcome of a retrospective cohort study on the rehabilitation of completely edentulous atrophic maxillae with immediately loaded zygomatic implants placed extra-maxillary

PURPOSE

To report retrospectively on the 5-year follow-up results of the rehabilitation of complete edentulous atrophied maxillae, using extra-maxillary zygomatic implants alone or in combination with conventional implants.

MATERIALS AND METHODS

This retrospective report includes an initial cohort of 39 patients (30 women and 9 men), with a mean age of 53 years, followed for 5 years. The patients were rehabilitated with 39 fixed prostheses and 169 implants (92 zygomatic implants inserted extra-maxillary and 77 conventional dental implants). A provisional prosthesis was manufactured and attached via multiunit abutments secured to the implants on the same day as implant placement. According to patient desires and each clinical situation, either an acrylic resin, a metal-acrylic or metal-ceramic final prosthesis was inserted approximately 6 months after implant placement. Outcome measures were: prosthesis success; implant success; complications; probing pocket depths; marginal bleeding; and marginal bone levels (only for conventional implants). Data were analysed with descriptive statistics.

RESULTS

Two patients died after 8 and 30 months of follow-up due to causes unrelated to their oral rehabilitations, and 5 patients dropped out of the study. No prosthesis was lost; one zygomatic implant was removed after 46 months of follow-up, giving cumulative success rates of 97% and 98.8% (patient and implant related, respectively). Twelve complications occurred in 12 patients: 5 sinus infections in 5 patients, all with a previous history of sinusitis and whose sinus membrane was disrupted during surgery; one oroantral communication (leading to removal of the implant), 2 all acrylic resin prostheses fractures, 1 ceramic crown fracture (on a metal-ceramic prosthesis); and 3 screw loosenings. Bleeding on probing was recorded in 6 patients (13 implants). Probing pocket depths >4 mm were present in 13 patients (23 implants) at 5 years of follow-up. The average (standard deviation) marginal bone loss on conventional implants was 1.16 mm (0.77 mm) in those 9 patients having the intraoral radiographs.

CONCLUSIONS

The long term outcome (5 years) of rehabilitations performed on patients with completely edentulous, severely atrophic maxillae supported by immediately loaded zygomatic implants alone, or in combination with conventional implants, is satisfactory.

Immediate loading of implants placed in patients with untreated periodontal disease: a 5-year prospective cohort study

PURPOSE

To report the 5-year outcome of immediately loaded dental implants in patients with untreated periodontal disease.

MATERIALS AND METHODS

This prospective cohort study included 103 consecutive patients (51 females and 52 males) with an average age of 52 years (range: 22 to 80 years) who were rehabilitated with 380 implants supporting 145 prostheses in both jaws (40 single; 33 partial and 72 complete rehabilitations). The implants were inserted in patients with active and untreated periodontitis. The patients did not receive any previous periodontal treatment before implant surgery, except for an oral hygiene session immediately before the implant surgery. In maintenance (every 6 months) patients received periodontal treatment as needed. Outcome measures were: prostheses failures; implant failures; complications; and marginal bone level changes.

RESULTS

Fifteen patients dropped out of the study (14.6%). Two patients lost two implants (FDI positions nos.12 and 42), rendering a cumulative survival rate of 97.9% and 99.4% at 5 years of followup using the patient and implant as unit of analysis, respectively. The average (standard deviation) marginal bone resorption was 0.71 mm (0.42 mm) at 5 years. Mechanical complications occurred in 14 patients, consisting of prostheses fractures (10 provisional prostheses and 4 definitive prostheses). Thirteen implants (3.9%) in 13 patients (14.8%) presented peri-implant pathology.

CONCLUSIONS

Within the limitations of this study, it is possible to conclude that the rehabilitation of patients with untreated periodontitis using immediately loaded dental implants is feasible in the medium-term, when periodontal therapy is provided after rehabilitation and the patients are regularly maintained.

Preliminary report on the outcome of tilted implants with longer lengths (20-25 mm) in low-density bone: one-year follow-up of a prospective cohort study

PURPOSE

The aim of this preliminary study was to report on the short-term outcome of tilted implants with 20 to 25 mm of length in immediate function with bicortical anchorage for prosthetic rehabilitation of complete edentulous jaws with low-density bone.

MATERIAL AND METHODS

Sixteen patients (with 25 study implants and 43 nonstudy implants) presenting low-density bone were included in a prospective single cohort study to evaluate the short-term outcome of partial and complete edentulous rehabilitations using implants with 20 to 25 mm of length (NobelSpeedy Groovy, Nobel Biocare AB, Gothenburg, Sweden) in immediate function with bicortical anchorage (maxilla: alveolar ridge and nasal corticals; mandible: mandibular corticals). The patients were followed between 6 and 26 months (average of 14 months). Outcome measures were implant survival, marginal bone remodeling, biological and mechanical complications assessed at 10 days, 2, 4, and 6 months, 1-year posttreatment, and thereafter every 6 months.

RESULTS

Two patients with four implants were lost to follow-up after 6 and 11 months. There were no implant failures, rendering a cumulative implant survival rate of 100%. The average marginal bone remodeling was 0.50 mm (SD = 0.34 mm) and 0.86 mm (SD = 0.46 mm), after 6 months and 1 year, respectively. There was one mechanical complication in one patient (abutment loosening) 1 month post-surgery.

CONCLUSION

Within the limitations of this study, the short-term outcome of prosthetic rehabilitations of patients with low-density bone using implants of 20 to 25 mm in length in immediate function with bicortical anchorage is viable judging by the high implant survival rate, low marginal bone remodeling, and low incidence of complications. Long-term evaluation of these implants through studies using a prospective design is mandatory.

Extramaxillary surgical technique: clinical outcome of 352 patients rehabilitated with 747 zygomatic implants with a follow-up between 6 months and 7 years

BACKGROUND

The use of zygomatic implants inserted in immediate function through the extramaxillary technique needs validation.

PURPOSE

To report the outcome of rehabilitating 352 patients with complete edentulous atrophied maxillae using 747 zygomatic implants in immediate function inserted through the extramaxillary technique.

MATERIALS AND METHODS

Three hundred-fifty-two consecutive edentulous patients with atrophic maxillae were rehabilitated between 2006 and 2012 with 747 zygomatic implants and 795 conventional implants. Implant and prosthetic cumulative survival and success rates were estimated through Kaplan-Meier product limit estimator. Biological and prosthetic complications were recorded after 10 days; 2, 4, and 6 months; and thereafter every 6 months.

RESULTS

Forty-three patients (12.2%) dropped-out, one patient lost the prosthesis (cumulative survival rate = 99.7%), and four patients lost 7 zygomatic implants, rendering an estimated cumulative survival rate of 98.2% (Kaplan-Meier). Ten patients lost 17 conventional implants (patient-specific and implant-specific cumulative survival rates of 96.7% and 97.9%, respectively). Biological complications were observed in 80 patients (22.7%) and resolved in the majority of situations, rendering an estimated cumulative success rate of 94.4% at 7 years for zygomatic implants (Kaplan-Meier). Mechanical complications occurred in 156 patients (44%), with one-third of these complications occurring in patients diagnosed with bruxism before the rehabilitation.

CONCLUSIONS

The rehabilitation of atrophic maxillae with zygomatic implants inserted through the extramaxillary technique in immediate function, alone or in combination with standard implants, is a viable procedure. Until the biomechanical aspects are more predictable and also because of the complexity of the surgical technique, this rehabilitation approach is not ready for every implant clinician to begin using in practice, and prior special training is recommended.

Immediate loading of 'All-on-4' maxillary prostheses using trans-sinus tilted implants without sinus bone grafting: a retrospective study reporting the 3-year outcome

PURPOSE

To report the outcome of trans-sinus tilted implants for the rehabilitation of the complete edentulous atrophic maxilla using the All-on-4 concept with immediate loading.

MATERIALS AND METHODS

This retrospective clinical study included 70 patients treated with 280 implants (Nobel Biocare), 83 of which were trans-sinus implants supporting 70 prostheses. The inclusion criteria were need of maxillary complete edentulous rehabilitation without enough bone height posterior to the canines to anchor the implants. The trans-sinus implant head was anchored on the bone available just posterior to the anterior sinus wall and inferior to the sinus floor. The trans-sinus implant body was inside the sinus, and its apex anchored in the bone between the anterior sinus wall and the nasal cortical. The nasal cortical was used, if necessary, to achieve a double bicortical anchorage. Implants were immediately loaded with cross-arch fixed prostheses. Follow-up examinations were performed after 10 days, 2, 4 and 6 months, and 1, 2 and 3 years. Radiographic evaluations were performed after 1 and 3 years of function. Outcome measures were success of the prostheses, success of the implants, complications, peri-implant marginal bone levels, and aesthetic and functional complaints. Survival was calculated at implant level and using the patient as the unit of analysis (first implant failure in any given patient) using life-table analysis.

RESULTS

Seven patients dropped out of the study. Three trans-sinus tilted implants were lost in 3 patients, giving a cumulative survival rate of 95.7% and 96.4% at patient and implant level, respectively. One conventional tilted implant was lost in 1 patient (one of the patients that lost a trans-sinus tilted implant), giving a cumulative survival rate of 98.1%. One straight implant was lost in one patient (a second patient that lost a trans-sinus implant), giving a cumulative survival rate of 98.6% and 99.3% at patient and implant level, respectively. The survival rate of prostheses was 100%. Sinusitis occurred in 2 patients (2.9%). The marginal bone resorption was on average (standard deviation) 0.96 mm (0.62 mm) and 1.14 mm (0.74 mm) for the trans-sinus tilted implants, 0.89 mm (0.54 mm) and 1.06 mm (0.71 mm) for the conventional tilted implants, and 0.62 mm (0.35 mm) and 1.15 mm (0.51 mm) for the straight implants after 1 and 3 years of follow-up, respectively.

CONCLUSIONS

The high survival rate registered at patient and implant level indicates that the outcome of immediately loaded trans-sinus implants for the rehabilitation of edentulous atrophic maxillae to avoid sinus lift procedures is a viable treatment in the short and medium term. Future studies should focus on the long-term outcome of this rehabilitation modality.

The prognosis of partial implant-supported fixed dental prostheses with cantilevers. A 5-year retrospective cohort study

PURPOSE

To report the outcome of implant-supported fixed partial prostheses with cantilevers at 5 years after loading.

MATERIAL AND METHODS

A total of 174 patients, 106 females and 68 males with 225 implants (maxilla: 149; mandible: 76), supporting 191 fixed dental prostheses (maxilla: 125; mandible: 66) were included. Inclusion criteria were patients rehabilitated with partial prostheses with cantilevers and sufficient amount of bone to place implants of at least 7 mm long. Primary outcome measures were prosthesis and implant success as well as biological and mechanical complications. The secondary outcome measure was peri-implant marginal bone loss.

RESULTS

Sixteen patients with 21 implants dropped out (9.2% of patients; 9.4% of implants). Three implants were lost in 3 patients. Two prostheses were lost rendering a survival estimation of 99.0% at 5 years (Kaplan-Meyer). Overall mean (standard deviation) bone level was 0.15 mm (0.34 mm), 1.56 mm (0.88 mm) and 1.88 mm (1.05 mm) at implant insertion, and 1 and 5 years after implant placement, respectively. The frequency at patient level of biological and mechanical complications was 2.9% and 27.6%, respectively.

CONCLUSIONS

Within the limitations of this study, it is possible to conclude that it is viable to use fixed implant-supported partial rehabilitation with a cantilever, judging by the 99% prosthetic success rate at 5 years. However, there is a relatively high frequency of complications to cope with in these rehabilitation.

Three-year outcome of a retrospective cohort study on the rehabilitation of completely edentulous atrophic maxillae with immediately loaded extra-maxillary zygomatic implants

AIM

To report retrospectively on the 3-year follow-up results in the rehabilitation of completely edentulous atrophied maxillae using extra-maxillary zygomatic implants.

MATERIALS AND METHODS

This retrospective report includes an initial cohort of 39 patients (30 women and 9 men), with a mean age of 53 years, which were followed up for 3 years. The patients were rehabilitated with 39 fixed prostheses and 169 implants (92 zygomatic and 77 regular implants). Final abutments were delivered at surgery stage and a provisional fixed dental prosthesis was manufactured and attached to the implants on the same day as surgery, achieving immediate function. Outcome measures were prosthesis success, implant success, complications, probing pocket depths (PPDs) and marginal bone levels (only for conventional implants). Data were analysed with descriptive and inferential analyses.

RESULTS

Five patients dropped out of the study and 1 patient died after 30 months of follow-up due to causes unrelated to the oral rehabilitation. No prosthesis or implant was lost, though 1 implant presented mobility at the 1-year follow-up but remained stable on subsequent follow-ups. Six complications occurred (18%): 5 cases of sinusitis in 5 patients preoperatively diagnosed with sinusitis and whose sinus membrane was disrupted during surgery, and 1 oro-antral communication. Median PPD values were 3 mm in all follow-up appointments (2, 4 and 6 months, 1, 2 and 3 years), comparable to the values of probing depths assessed for standard implants.

CONCLUSIONS

Within the limitations of this study, the medium-term outcome (3 years) indicates that severely atrophied completely edentulous maxilla rehabilitations supported by immediately loaded zygomatic implants are viable.

Partial rehabilitation of the posterior edentulous maxilla using axial and tilted implants in immediate function to avoid bone grafting

There is a need to create rehabilitation solutions for partial edentulism in the posterior maxilla, thereby reducing the need for grafting in these areas. The purpose of this study was to report the results of partial edentulism rehabilitation in the posterior maxilla with a three- to four-unit bridge supported by two implants: anterior implant placed in axial position and posterior implant tilted distally. A theoretical analysis of the concept including a biomechanical discussion is also provided.

MATERIALS AND METHODS

The clinical study included 35 patients (21 women, 14 men) with an age range of 37 to 80 years (mean = 55.5 years), rehabilitated with an implant-supported partial bridge, followed between 4 months and 8 years, with a mean follow-up time of 53 months. ASSESSMENT DATA:The success criteria included clinical parameters (ie, implant fulfilled its purported function as support for reconstruction; was stable when individually and manually tested; had absence of infection; demonstrated a good esthetic outcome of the rehabilitation; allowed fabrication of the implant-supported fixed prosthesis, which provided patient comfort and hygiene) and radiographic parameters (ie, implant probability of long-term stability, as judged by annual bone loss). The implant survival estimate was computed using the Kaplan-Meier product limit estimator. Data were analyzed with descriptive and inferential analyses.

RESULTS

The survival rates were 97.1% and 98.8% at 8 years (Kaplan-Meier), using the patient and implant as units of analysis, respectively. The overall average marginal bone resorption was 1.05 mm (SD = 0.65 mm) at 1-year follow-up, and 1.47 mm (SD = 0.37 mm) at 5-year follow-up, with no significant differences between axial and tilted implants in the 1-year (P = 0.107) and 5-year (P = 0.211) evaluations. DISCUSSION OF RESULTS:The results indicate that within the limitations of this preliminary study the present protocol is valid for the rehabilitation of partial edentulism in the posterior maxilla. The clinical results confirmed the theoretical analysis on biomechanics and load distribution, with high survival and success rates in the long-term, low implant marginal bone resorption, and low frequencies of complications.

Implants (3.3 mm diameter) for the rehabilitation of edentulous posterior regions: a retrospective clinical study with up to 11 years of follow-up

BACKGROUND

There is limited evidence for the use of narrow-diameter implants for rehabilitation of the posterior regions of the jaws using different surgical techniques.

PURPOSE

The purpose of this study was to report the clinical results of implant-supported prosthetic rehabilitations in the posterior regions of both jaws, using narrow-diameter implants.

MATERIALS AND METHODS

The study included 147 patients (115 males and 32 females), with an age range of 26 to 77 years (mean = 47.5 years), with a total of 247 implants inserted and followed between 1 and 11 years, with a median follow-up time of 5 years. The patients were in need of fixed prosthetic implant-supported rehabilitations in the posterior region of the jaw, presenting a reduced interradicular bone or a thin alveolar crest. The implant survival estimate was computed using the Kaplan-Meier product limit estimator.

RESULTS

The survival rate for narrow diameter implants was 95.1% at 11 years (Kaplan-Meier), with a distribution of 91.4% at 11 years, 95.9% at 10 years, and 95.5% at 9 years for the two-stage, one-stage, and immediate function techniques, respectively. The mean marginal bone resorption recorded at 1, 5, and 10 years were 1.16, 1.53, and 1.74 mm, respectively. Backward conditional logistic regression identified "type of implant" as a strong protective factor against implant failure (MkIII and NobelSpeedy implants compared to the MkII implant; OR = 0.14), and "type of rehabilitation" as a strong risk factor for implant failure (partial rehabilitations compared to single teeth rehabilitations; OR = 4.75).

CONCLUSIONS

The results indicate that within the limitations of this study, the use of narrow-diameter implants for the prosthetic rehabilitation of posterior regions of the jaws is viable, with good outcomes in the long-term, irrespective of the surgical technique implemented.

The rehabilitation of completely edentulous maxillae with different degrees of resorption with four or more immediately loaded implants: a 5-year retrospective study and a new classification

PURPOSE

To report the long-term outcome of immediately loaded implants in the rehabilitations of completely edentulous maxillae with different classifications. The secondary aim was to evaluate the influence of possible explanatory variables on the incidence of biological and mechanical complications.

MATERIAL AND METHODS

In total, 221 patients were consecutively included and classified into four groups that allowed implant placement in a vertical position: Group 1 (bone available up to first molar), Group 2 (bone available up to second premolar), Group 3 (bone available up to first premolar) and Group 4 (bone available up to canine). Outcome measures were prosthesis and implant survival, and biological and mechanical complications.

RESULTS

A total of 995 implants were placed. Eighteen patients (8% of the sample) dropped out of the study. After 5 years, three patients lost their prosthesis due to implant failures, giving a survival rate of 98.6%; 25 patients lost 41 implants, giving a survival rate of 88.7% (25/221) and an implant-specific survival rate of 95.8% (41/995). According to the edentulism classification, the patient-specific survival rate after 5 years was 78.6% for Group 1, 89.3% for Group 2, 92.4% for Group 3 and 91.7% for Group 4. In total, 129 biological complications occurred affecting 129 implants (13%) in 66 patients (30%). Smoking was identified as a risk factor for the incidence of biological complications with an OR of 3.03 (95% CI 2.03-4.56; P < 0.0001), while 'gender' (male; OR = 0.56; 95% CI 0.37-0.85; P = 0.007) was a factor that had a protective effect. A total of 170 mechanical complications occurred, affecting 170 implants (17%) in 71 patients (38%). Bruxism was identified as a risk factor for the incidence of mechanical complications with an OR of 60.95 (95% CI 21.40-173.54; P < 0.0001), while a Group 2 edentulism classification had a protective effect for the incidence of mechanical complications with an OR of 0.22 (95% CI 0.07-0.71; P = 0.011).

CONCLUSIONS

It is a viable treatment option to rehabilitate completely edentulous maxillae using four implants or more to support a fixed prosthesis.

Short implants in posterior jaws. A prospective 1-year study

BACKGROUND

There is limited evidence for the outcome of short implants (7 mm) to rehabilitate posterior jaws.

PURPOSE

To report on the outcome of 7 mm short implants in the rehabilitation of posterior areas of atrophic jaws 1 year 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 11 patients (18 implants) a provisional acrylic resin crown or bridge was manufactured and attached to the implants on the same day as the surgery, achieving immediate function. The final prosthesis was typically delivered after 6 months. Outcome measures were implant survival calculated at patient and implant levels, complications and peri-implant marginal bone resorption calculated at patient level.

RESULTS

Three patients with 5 implants were lost to follow-up after 7 months. Implant losses occurred in 6 of the 127 patients and 10 of the 217 implants placed failed, giving a success rate of 95% at patient and implant level after 1 year of follow-up. The mean marginal bone resorption after 1 year of follow-up was 1.27 mm (SD = 0.67 mm). The only complication registered was a periimplant pathology at one implant.

CONCLUSIONS

One year after loading, 7 mm short implants provided good success rates (95% at patient level and implant level) suggesting that the use of short implants is a viable concept, however longer follow-ups are needed to confirm these preliminary results.

A new approach for maxilla reconstruction

PURPOSE

The aim of the present prospective cohort study was to report on an approach for maxillary reconstruction with autogenous bone grafts allowing implant placement for immediate function with fixed bridges after 6 months.

MATERIALS AND METHODS

A total of 35 bilateral bone grafting procedures were performed on 35 consecutive patients (mean age 54.5 years). The iliac crest was used as donor site for all patients. The method for retaining the immediate prosthesis after bone graft ranged from mucosa retention (6 patients), implant retention (10 patients with immediate-function implants placed in non-grafted bone at the same surgical step as the bone graft procedure), teeth retention (6 patients) or palatal implant retention (13 patients). The graft was considered to be successful when it allowed the placement of the planned implants for immediate function rehabilitation with a fixed bridge.

RESULTS

All bone-grafting procedures were successful, allowing all patients to be rehabilitated after 6 months with a fixed bridge supported by immediate-function implants. The cumulative survival rate of the palatal implants was 94% after 2 months. A total of 219 immediate-function implants were placed in grafted bone and loaded occlusally. Two patients dropped out of the study 2 and 4 months after the bone graft procedure, while one patient with four implants dropped out of the study 13 months after the rehabilitation with implants. The cumulative survival rate of the implants was 97.3% at 1-year and 96.7% at 5-years (up to 129 months; minimum of 29 months; median of 52.5 months). Seven implants failed to integrate in the grafted bone. The marginal bone resorption for the implants placed in grafted areas at 1-year and 5-year follow-up was 2.0 mm (SD = 1.2 mm) and 2.0mm (SD = 1.1 mm), respectively.

CONCLUSIONS

Maxilla reconstruction with autogenous grafted bone is a viable process, allowing, in some cases, the use of a removable or fixed prosthetic rehabilitation immediately after grafting. Maxillary rehabilitation with immediate-function implants in grafted bone is possible, with the implant success rate achieved at 5 years comparable to other rehabilitations with implants placed in grafted bone, but lower than the results obtained with implants placed in residual bone.

Flap vs. flapless surgical techniques at immediate implant function in predominantly soft bone for rehabilitation of partial edentulism: a prospective cohort study with follow-up of 1 year

PURPOSE

The aim of this study was to report on the rehabilitation of partial edentulism with immediate function implants placed in predominantly soft bone with flap and flapless surgical techniques.

MATERIALS AND METHODS

The prospective clinical study comprises 72 implants (50 in the maxilla and 22 in the mandible) placed in 41 consecutively included patients rehabilitated from partial edentulism, followed for 1 year. An implant specially designed for immediate function was used. The evaluation included clinical examinations and radiographic assessment of the marginal bone level at 6 months and 1 year. The outcome measure was the implant success, evaluated using the following implant success criteria: clinical stability (fixed dental prostheses removed and implants individually checked); fulfilled purported function without any discomfort to the patient; no suppuration or infection present; no radiolucent areas around the implants at time of evaluation; and no aesthetic complaints from the patient.

RESULTS

No dropouts were registered during the follow-up of the study. The overall cumulative survival rate at 1 year was 98.6% (1 implant lost), with 100% for the implants placed with the flap surgical technique, and 96.9% for the implants placed with the flapless surgical technique. The overall average marginal bone resorption was 1.6mm (SD=1.1mm) at 1-year follow-up, with 1.4mm (SD=0.8mm) and 2.0mm (SD =1.4mm) for the flap and flapless surgical technique study groups, respectively. The complications registered were: peri-implant pathology (3 implants in 3 patients); fracture of the provisional crown/prosthesis (2 patients); crown loosening (1 patient) and prosthetic screw loosening (1 patient).

CONCLUSIONS

The placement of the specially designed implant for immediate function in predominantly soft bone is viable, as given by the overall 98.6% cumulative survival rate, and the rehabilitation using flapless surgery is safe and predictable. However, the flapless technique revealed more marginal bone resorption compared with the flap technique. Extra care should be taken in the flapless approach with respect to the inclusion criteria and difficulty of the surgery.

Peri-implant maintenance of immediate function implants: a pilot study comparing hyaluronic acid and chlorhexidine

INTRODUCTION

In implants, maintenance assumes an important role. The role of chlorhexidine (CHX) is well known in maintenance, while only limited evidence exists on the practical use of hyaluronic acid (HA). The objective of this study was to compare the health status of the peri-implant complex (hard and soft tissues surrounding the implant) during the healing period of immediate function implants, using HA or CHX gels in the patient's maintenance protocol. STUDY POPULATION AND METHODOLOGY: Thirty complete edentulous patients, with four immediate function Brånemark System implants placed in the mandible (total of 120 implants), were randomly assigned to two groups (HA and CHX) using only these two chemicals in their daily implant self-care. Both groups were followed up for 6 months, with clinical observations on the 10th day, 2 months, 4 months and 6 months post-surgically.

RESULTS

During the course of the study, HA and CHX produced good results in maintaining a healthy peri-implant complex in immediate function implants for complete rehabilitations in the edentulous mandible. Statistically significant differences were found in favour of the HA group in the modified bleeding index on the second observation (P = 0.003). The difference was more marked in the axial implants placed in the fifth sextant (P = 0.05). Correlation coefficient between plaque and bleeding index revealed a potentially better result for CHX at 6 months.

CONCLUSION

The findings point out the importance of a maintenance protocol in immediate function implants. Both chemicals are valid tools for implant maintenance. The authors suggest that it might be advantageous to administer HA in the first 2 months and CHX between 2 and 6 months.

Short Implants Placed One-Stage in Maxillae and Mandibles: A Retrospective Clinical Study with 1 to 9 Years of Follow-Up

BACKGROUND

The use of short implants (7-8.5 mm) has historically been associated with lower survival rates than for longer implants. However, recent clinical studies indicate that short implants may support most prosthetic restorations quite adequately, but still clinical documentation is sparse.

PURPOSE

The purpose of this study was to report on the placement of short Brånemark implants, testing the hypothesis that short implants in atrophied jaws might give similar long-term implant survival rates as longer implants used in larger bone volumes.

MATERIALS AND METHODS

This retrospective clinical study included 237 consecutively treated patients with 408 short Brånemark implants supporting 151 fixed prostheses. One hundred thirty-one of the implants were 7-mm long, and 277 were 8.5-mm long. Final abutments were delivered at the time of surgery, and final prostheses were delivered 4 to 6 months later.

RESULTS

One hundred and twenty six of the 7-mm implants (96%) have passed the 1-year follow-up; 110 (84%), the 2-year follow-up; and 88 (67%), the 5-year follow-up. Five implants failed in four patients before the 6-month follow-up, giving a cumulative survival rate of 96.2% at 5 years. The average bone resorption was 1 mm (SD=0.6 mm) after the first year and 1.8 mm (SD=0.8 mm) after the fifth year of function. Two hundred sixty nine of the 8.5-mm implants (97%) have passed the 1-year follow-up; 220 (79%), the 2-year follow-up; and 142 (51%), the 5-year follow-up. Eight implants failed in seven patients before the 6-month follow-up, giving a cumulative survival rate of 97.1% at 5 years. The average bone resorption was 1.3 mm (SD=0.8 mm) after the first year and 2.2 mm (SD=0.9 mm) after the fifth year of function.

CONCLUSIONS

The cumulative survival rates of 96.2 and 97.1% at 5 years for implants of 7.0- and 8.5-mm length, respectively, indicate that one-stage short Brånemark implants used in both jaws is a viable concept.

A Pilot Study of Complete Edentulous Rehabilitation with Immediate Function Using a New Implant Design: Case Series

BACKGROUND

The current investigation focuses on new implant designs for increased predictability in clinically demanding situations. Microtextured implant surfaces create favorable conditions for enhanced osseointegration of dental implants compared to implants with a smooth surface, and the macroscopic implant design may influence implant stability.

PURPOSE

The aim of the present study was to retrospectively evaluate the clinical performance of a novel implant design in the rehabilitation of completely edentulous jaws and in combination with an immediate function protocol.

MATERIALS AND METHODS

Forty-six consecutive patients received 189 study implants (NobelSpeedy concept implant, Nobel Biocare AB, Göteborg, Sweden) supporting 53 full-arch all-acrylic prostheses (44 maxilla, 9 mandible). The majority (66%) of the reconstructions were supported by four implants, of which the two posterior implants were tilted. All patients were followed for a minimum of 1 year. Radiographic assessment of the marginal bone level was performed.

RESULTS

Two implants were lost in two patients, rendering a 1-year cumulative clinical survival rate of 98.9%. The marginal bone level was, on average, situated 1.2 +/- 0.7 mm below the implant-abutment interface after 1 year of loading. Good soft tissue health and overall esthetic outcome was reported.

CONCLUSIONS

The results of the present pilot study indicate that fully edentulous jaws with various types of bone can be treated with high success and good esthetics using immediately loaded implants with the presented design, and that favorable marginal bone levels can be maintained.

Non-surgical treatment of peri-implant pathology

INTRODUCTION

Peri-implant pathologies consist of an inflammatory process affecting the soft and hard tissues surrounding the implants. Chlorhexidine is considered the gold standard antiseptic, with a large variety of choice in administration. In this study, a protocol for the irrigation of peri-implant pockets with a chlorhexidine gel, using a plastic needle for the delivery of the product into the peri-implant pockets is described.

STUDY PARTICIPANTS AND METHODS

Nine patients with at least one implant presenting peri-implant pathology (inflamed soft tissue associated with bone loss around the implant) were enrolled in this prospective clinical study, and followed-up for 1 year, where clinical parameters such as modified plaque index, modified bleeding index, probing pocket depths, attachment levels were assessed at baseline, 1 month, and 1 year after implementation of the treatment protocol.

RESULTS

Treatment success was achieved in eight of the nine patients (and in 11 of the 13 implants) according to the success criteria adopted by the authors of this study.

DISCUSSION

Infection control lies at the heart of peri-implant treatment. The control of three factors such as optimal diagnosis, removal of the aetiological factor of the disease (proper removal of debris and decontamination of the peri-implant sulcus/pocket) and a good patient's oral hygiene self-care represents the key to success, resulting in good treatment outcomes when managing peri-implant pathologies. The protocol used (irrigation of peri-implant pockets with chlorhexidine gel delivered by a plastic needle) is considered to be of utility.