Retrospective cohort study of 4591 Straumann implants in private practice setting, with up to 10-year follow-up. Part 1: multivariate survival analysis.

OBJECTIVE: The purpose of this retrospective, noninterventional, open cohort study is to report on the long-term survival of dental implants, in private practice representing the daily realities of implant treatment. The data are analyzed to discern statistical relationships between explanatory variables and implant failure. MATERIALS AND METHODS: A total of 4591 Straumann implants were placed in 2060 patients between 1999 and 2012. Patients were evaluated after 2-3 months, 1, 3, 5, and 7 years and, in some cases, up to 10 years. The cumulative survival rate (CSR) was calculated according to the life table method and illustrated with Kaplan-Meier survival curves. Univariate analysis was performed to investigate the association between study variables and time to implant-failure. Variables with P -value < 0.15 were further selected for a multivariate analysis. Statistical methods which take into account the fact that some patients have more than one implant (therefore, dependency between implants within mouth) had been applied. RESULTS: At the implant level, the cumulative survival rates at 3, 5, and 7 years were 99.3%, 99.0%, and 98.4%, respectively, and at the patient level, they were 98.6%, 97.7%, and 95.9%, respectively. After adjustment to possible confounders, the multivariate analysis identified a relationship between the following risk indicators for implant failure: implant location, length and design, timing of implantation, bone grafting procedures and gender. Tissue-Level implants (n = 3863) had a very high survival rate of 99% at 3 years, which was maintained over the entire study period. Bone-Level implants (n = 600) were as predictable with a survival rate of 99% up to 3 years, while Tapered Effect implants (n = 128) demonstrated a lower survival rate of 95% at 5 years. Short 6-mm implants in the mandibular posterior sites had a high survival rate of 100%, while in maxillary posterior positions a survival rate of only 87% was achieved. Patient factors such as smoking, autoimmune disease, and penicillin allergy were tending to associate with higher failure rates. CONCLUSION: High long-term survival rates were observed for a large cohort of Straumann implants. Tissue- and Bone-Level implants had higher survival rates than Tapered Effect implants, and although short implants faired well in the mandibular posterior sites, they faired less well in the maxillary posterior sites. The study represents private practice insight into large-scale, long-term implant results.

10-year survival rate and the incidence of peri-implant disease of 374 titanium dental implants with a SLA surface: a prospective cohort study in 177 fully and partially edentulous patients.

PURPOSE: This prospective cohort study evaluates the 10-year survival and incidence of peri-implant disease at implant and patient level of sandblasted, large grid, and acid-etched titanium dental implants (Straumann, soft tissue level, SLA surface) in fully and partially edentulous patients. MATERIAL AND METHODS: Patients who had dental implant surgery in the period between November 1997 and June 2001, with a follow-up of at least 10 years, were investigated for clinical and radiological examination. Among the 506 inserted dental implants in 250 patients, 10-year data regarding the outcome of implants were available for 374 dental implants in 177 patients. In the current study, peri-implantitis was defined as advanced bone loss (≧1.5 mm. postloading) in combination with bleeding on probing. RESULTS: At 10-year follow-up, only one implant was lost (0.3%) 2 months after implant surgery due to insufficient osseointegration. The average bone loss at 10 year postloading was 0.52 mm. Advanced bone loss at 10-year follow-up was present in 35 dental implants (9.8%). Seven percent of the observed dental implants showed bleeding on probing in combination with advanced bone loss and 4.2% when setting the threshold for advanced bone loss at 2.0 mm. Advanced bone loss without bleeding on probing was present in 2.8% of all implants. CONCLUSION: In this prospective study, the 10-year survival rate at implant and patient level was 99.7% and 99.4%, respectively. Peri-implantitis was present in 7% of the observed dental implants according to the above-mentioned definition of peri-implantitis. This study shows that SLA implants offer predictable long-term results as support in the treatment of fully and partially edentulous patients.

Radiographic bone loss around dental implants: a large-cohort, long-term follow-up revealing prevalence and predictive factors.

OBJECTIVE: This retrospective study analyzed radiographic bone levels of 10,871 dental implants in a cohort of 4,247 patients over a 22-year period. The objectives of the study were to assess and explore risk factors associated with the radiographic bone level of dental implants. METHOD AND MATERIALS: A longitudinal observational cohort study based on data collected from 1995 to 2019 was conducted on implants placed by a single periodontist. Inclusion criteria included both partially and fully edentulous sites. Exclusion criteria were patients who were considered ASA 3 or greater. Information on medical and dental status prior to implant placement such as diabetes and smoking were included in the analysis. Implant factors such as the implant characteristics (length and diameter) and surgical site were recorded. The outcome assessed was the prevalence of bone loss around implants and any associative factors related to the bone loss. RESULTS: Overall, dental implants lost an average of 0.05 ± 0.38 mm of bone 2 to 3 years after placement and 0.21 ± 0.64 mm 8 years after placement. The soft tissue condition was evaluated using the Implant Mucosal Index (IMI), and bone loss around dental implants was significantly higher when bleeding on probing was multi-point and moderate, multi-point and profuse, and when infection with suppuration was recorded. The mean difference in bone level between smokers and nonsmokers was 0.26 mm (P < .01) over a 4-year period. A mean difference of 0.10 mm (P = .04) in bone loss over 4 years was found between those with an autoimmune disease compared to those without. The diameter of the implant and immediate loading of the dental implant did not influence the radiographic bone levels over time. CONCLUSIONS: This large dataset of dental implants highlights predictive risk factors for bone loss around dental implants and the impact these risk factors have on the implant bone level. Consideration of these risk factors by both the dental team and the patient prior to dental implant placement will promote success of the treatment.

Periodontal disease as a risk for dental implant failure over time: a long-term historical cohort study.

OBJECTIVES: To evaluate the long-term survival rates of dental implants according to the patient's periodontal status, as well as to estimate if the effect of periodontal status regarding implant failure is constant throughout the long-term follow-up. MATERIALS AND METHODS: This was a historical prospective cohort study design of all consecutive patients operated from 1996 to 2006 at a periodontal clinic. The cohort consisted of 736 patients, with a total of 2336 dental implants. An extended Cox proportional hazards model, which includes interaction terms between survival time and variables of interest, was used. RESULTS: Patients' mean (SD) age was 51.13 (12.35). The follow-up time was up to 144 months, with a mean (SD) of 54.4 (35.6) months. The overall implant raw survival rate was 95.9%. The Kaplan-Meier estimates for the cumulative survival rate (CSR) at 108 months were 0.96 and 0.95 for implants inserted into healthy and moderate chronic periodontal patients, respectively. The CSR declined to 0.88 at 108 months for the severe periodontitis group. The extended Cox model revealed that severe chronic status turned out to be a significant risk factor for implant failure after 50 months of follow-up [hazard ratio (HR)=8.06; p<0.01]. The extended Cox model for smoking indicates a near-significant effect after 50 months (HR=2.76; p=0.061). CONCLUSIONS: Periodontal status and smoking are significant risk factors for late implant failures. The HR for periodontal and smoking status are not constant throughout the follow-up period.

Long term clinical performance of 10 871 dental implants with up to 22 years of follow-up: A cohort study in 4247 patients.

BACKGROUND: The present retrospective study was aimed to assess the long-term clinical performance of dental implants in a cohort study of 4247 patients. METHODS: A longitudinal observational cohort study was done on all implants performed by a single periodontist from July 1995 to April 2019. The main outcome variables of this study were implant failure and marginal bone level around implants. RESULTS: The study participants received a total of 10 871 implants with a mean of 2.56 implants per patient. The cohort was followed-up to 22.2 years (mean = 4.5 ± 4.2). Among the 4247 patients of the current study, 140 patients (3.3%) experienced a combined total of 178 implant failures. According to life table analysis, at the implant level the cumulative survival rate at 3, 5, 10, and 15 years was 98.9%, 98.5%, 96.8%, and 94.0%, respectively while at patient level was 97.4%, 96.7%, 92.5%, and 86% at 3, 5, 10, and 15 years. Patients with multiple units were at a greater risk for having an implant failure. Baseline bone level was 0.09 ± 0.28 mm while at 8-10 years the mean bone level was 0.49 ± 0.74 mm. The incidence of peri-implant mucositis at the implant level was 9.4% at 2-3 years, 9.3% at 4-5 years, 12.1% at 6-7 years, and 11.9% at 8-10 years. The incidence of peri-implantitis was 2%, 2.6%, 3.2%, and 7.1% at 2-3, 4-5, 6-7, and 8-10 years, respectively. Cigarette smoking and diabetes mellitus were positively correlated with implant failure. CONCLUSIONS: Though the results are promising and encouraging in terms of survival and bone level over time, it is important to emphasize the potential risk factors and consider them prior to dental implant placement.

Retrospective cohort study of 4,591 dental implants: Analysis of risk indicators for bone loss and prevalence of peri-implant mucositis and peri-implantitis.

BACKGROUND: Due to the risk of peri-implantitis, following dental implant placement, this study aimed to evaluate risk indicators associated with marginal bone loss from a retrospective open cohort study of 4,591 dental implants, placed in private practice, with 5- to 10-year follow-up. Furthermore, the prevalence of mucositis and peri-implantitis among the study cohort was evaluated, comparing strict versus relaxed criteria for bleeding on probing. METHODS: Periapical radiographs were used to evaluate changes in crestal bone level. Peri-implant soft tissue was evaluated using an ordinal mucosal index in comparison with the conventional binary threshold for bleeding (i.e., present or not). Periodontal probing depth was not evaluated. Linear mixed models were used to evaluate bone level over time, and other risk indicators, at the patient and implant level. RESULTS: Risk indicators found to have a significant impact on bone level included: autoimmune disease, heavy smoking, bisphosphonate therapy, implant location, diameter and design, and the presence of a bone defect at site of implantation. The prevalence of mucositis at the implant level was 38.6% versus 14.2% at 6 to 7 years, when using strict versus relaxed criteria, respectively. The prevalence of peri-implantitis after 6 to 7 years was 4.7% and 3.6% when using strict versus relaxed criteria, respectively. CONCLUSIONS: The results of this study identify several risk factors associated with bone loss. Furthermore, the prevalence of mucositis and peri-implantitis was shown to be lower at both the implant and the patient when using strict versus relaxed criteria based on the assessment of oral health surrounding dental implants.

Retrospective Cohort Study of 4,591 Straumann Implants Placed in 2,060 Patients in Private Practice with up to 10-Year Follow-up: The Relationship Between Crestal Bone Level and Soft Tissue Condition.

PURPOSE: The purpose of this report is to describe the crestal bone level (CBL) around implants of various designs, describe the peri-implant soft tissue condition, and evaluate the relationship between the two over time. MATERIALS AND METHODS: This retrospective cohort study reports on 2,060 patients with 4,591 implants evaluated after 3 months; 1, 3, 5, and 7 years; and up to 10 years. Periapical radiographs were used to evaluate changes in CBL. The peri-implant soft tissue was evaluated using a modified Bleeding Index termed the Implant Mucosal Index (IMI) where: 0 = no bleeding; 1 = minimal, single-point bleeding; 2 = moderate, multipoint bleeding; 3 = profuse, multipoint bleeding; and 4 = suppuration. RESULTS: At 3 months, the mean CBL was 0.06 ± 0.22 mm; by 8 to 10 years, it had increased to 0.44 ± 0.81 mm. The median CBL remained stable throughout the study at < 0.1 mm. At 8 to 10 years, 15% of implants exhibited a CBL > 1.02 mm, and 5% exhibited a CBL > 2.28 mm. More than 50% of patients experienced some bleeding, as seen by an IMI ≥ 1 during follow-up. A positive correlation was found between IMI and CBL, as shown by a mean CBL after 4 years of 0.33 mm, 0.71 mm, and 1.52 mm for IMI = 2, 3, and 4, respectively. One exception was between IMI = 0 and IMI = 1, where no significant difference was found and bone loss was minimal. CONCLUSION: Bone loss, as measured by changes in CBL during the first 10 years of implant life spans, was minimal for most implants. Nevertheless, it is not unusual to observe implants with advanced bone loss. The soft tissue condition is a good indicator of bone loss. Time alone and minimal bleeding did not correlate with bone loss, but care should be taken for implants with profuse bleeding or suppuration.

Long Term Follow-Up of Dental Implants Placed in Autologous Onlay Bone Graft.

PURPOSE: The aim of this study was to evaluate the efficacy of autologous intraoral onlay bone grafting (OBG) in correlation with long-term survival rates of dental implants placed in the augmented bone. MATERIALS AND METHODS: A retrospective study was conducted on 214 patients who received a total of 633 dental implants placed in 224 autologous intraoral block OBG augmentations, combined with Bio-Oss - mixed with platelet-rich plasma (PRP) and covered by platelet-poor plasma (PPP) - as scaffold, with a follow-up time up to 137 months (mean 39.9 ± 30.9 months). RESULTS: A total of 216 OBG cases were successful (96.4%), and most of the augmentations were uneventful (88.4%). Bone graft exposure was moderately associated with bone graft failure (χ(2) = 3.76, p = .052). The healing period after implant placement was 4-6 months (mean 5.6 ± 2.56). The majority of the 591 implants survived (93.4%). The cumulative survival rate of the implants was 83%. CONCLUSIONS: We suggest that augmentation of severely atrophied jaw bone through the placement of horizontal and/or vertical intraoral OBGs in combination with Bio-Oss saturated with PRP and covered by PPP should be considered a reliable, safe, and very effective surgical technique for obtaining high bone graft survival rate and high long-term implant survival rate.

The importance of histopathological diagnosis in the management of lesions presenting as peri-implantitis.

PURPOSE: This study is a histopathological analysis of lesions clinically diagnosed as peri-implantitis (PI). MATERIALS AND METHODS: This retrospective study included microscopic findings in 117 peri-implant biopsies from lesions presenting clinical and radiographic features of peri-implantitis. RESULTS: The study group included 117 biopsies, mean age 55.2 years; 60.9% of biopsies were from failing implants during explantation, the remaining from surviving implants. All cases showed microscopic evidence for inflammation; however, although 41% exhibited only nonspecific inflammation, 29.9% exhibited actinomyces-related inflammation, 18.8% pyogenic granuloma (PG), and 10.3% giant cell granuloma (GCG). Differences in implant failure rates between pathological diagnostic groups were not statistically significant. Lesions with simple inflammation could not be distinguished clinically or radiographically from the potentially destructive lesions. CONCLUSIONS: There were no clinical features which could distinguish PI with simple inflammation from potentially destructive lesions mimicking PI, such as GCG, PG, and actinomycosis. However, to control GCG and PG surgical procedures would be recommended, actinomycosis would indicate specific antibiotics, whereas in nonspecific inflammation, these measures may not be indicated. The results of the present study provide evidence for the importance of early microscopic examination of lesions presenting clinically as peri-implantitis, a step toward more accurate diagnosis and improved treatment of PI and lesions mimicking PI.

The temporomandibular opening index, report of headache and TMD, and implications for screening in general practice: an initial study.

OBJECTIVE: The cardinal signs and symptoms of temporomandibular disorder (TMD) are pain in joints and/or muscles, joint sounds, and limitation of movement. They are also associated with other complaints, one of which is headache. Myogenous TMD patients can be divided into those with a high and low temporomandibular opening index (TOI). These two subgroups appear to vary in several ways, including symptom severity. The objective was to assess the relationship between reported headache and TMD patients and a control group with no TMD and to compare the report of headache in high- and low-TOI myogenous TMD patients. METHOD AND MATERIALS: Sixty-six patients with TMD were included in the study. Fortythree were diagnosed with myogenous TMD, 23 with arthrogenous TMD, and 20 with no TMD were included as a control. Patients reported a history of headache using a four-point Verbal Rating Scale for both severity and frequency. Multiple logistic regression analysis was performed, after adjusting for confounders of sex and age. This helped investigate the association between the study groups and reported headache. Seventeen of the myogenous TMD patients were studied further. Seven were assigned to the high and 10 to the low-TOI group. Mean ages were 38.43 years and 33.00 years respectively. The Mann Whitney test was used to examine the difference in report of headache between these two groups. RESULTS: 76.7% of the myogenous group, 26.1% of the arthrogenous group, and 35% of the control group reported headache. Age and myogenous TMD were significantly associated with reported headache (P = .001 and .01, respectively). Myogenous TMD is a significant risk factor (OR = 5.20, P = .01) for reported headache while arthrogenous TMD is not (OR = 0.75, P = .69) A significant difference in report of headache between the two myogenous TMD groups was found (P = .0067). CONCLUSION: The risk for reported headache is 5.20-times greater for myogenous TMD patients compared to the control group, but no difference was noted between the arthrogenous TMD and the control group. Age serves as a mild protective for reported headache. Younger patients tend to report more headaches. More frequent and severe headache occurred in the high-TOI group. This study serves as a reminder for clinicians in general practice to consider the effect of comorbidity when faced with TMD patients with headache.

The temporomandibular opening index and condylar asymmetry in myogenous TMD and non-TMD patients: report of a pilot study.

OBJECTIVE: The temporomandibular opening index (TOI) is endfeel distance divided by active and passive mouth opening. The asymmetry index (AI) is a measure of difference in left and right condylar heights. This study examined the relationship between AI and TOI in myogenous TMD and non-TMD patients. METHOD AND MATERIALS: Fourteen myogenous TMD patients diagnosed by the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were recruited (1 man and 13 women) and 14 non-TMD patients (6 men and 8 women) were included as controls. Differences between the TMD patients and control group of non-TMD patients were determined by the two-tailed t test, while multiple linear regression analysis was used to examine the correlation between AI and TOI adjusting for sex and age. RESULTS: AI and TOI were significantly higher (P = .001 and P = .045, respectively) among TMD patients. A significant positive correlation was found between TOI and AI for the TMD group (r = 0.84, P = .01) but not for the control group. CONCLUSION: A positive correlation was found between TOI and AI in the myogenous TMD group.

Medico-legal aspects of altered sensation following endodontic treatment: a retrospective case series.

OBJECTIVE: The objective of this study was to analyze cases of liability claims related to persistent altered sensation following endodontic treatments so as to characterize the medico-legal aspects of this complication. STUDY DESIGN: A comprehensive search of an Israeli professional liability insurance database was conducted to retrospectively identify and analyze cases of persistent altered sensation following endodontic treatment. RESULTS: Sixteen claims of persistent altered sensation following endodontic treatments were identified and analyzed. The typical profile of a claim was a female patient who underwent an endodontic treatment at a second mandibular molar, which was associated with overfilling. A significant correlation between the tooth location and the suggested cause of nerve injury was found. None of the claims were reported by the practitioners, and all cases were identified as a result of the patient's demand for financial compensation, either directly or by legal actions. CONCLUSIONS: When a nerve injury is diagnosed, the treating practitioner should be encouraged to seek medical and legal assistance so as to prevent permanent damage and to enable a better medico-legal response.