Bruno Chrcanovic | Malmö University (original) (raw)

Papers by Bruno Chrcanovic

Purpose: To assess the influence of several factors on the prevalence of dental implant failure, ... more Purpose: To assess the influence of several factors on the prevalence of dental implant failure, with special consideration of the placement of implants by different dental surgeons. Materials and Methods: This retrospective study is based on 2,670 patients who received 10,096 implants at one specialist clinic. Only the data of patients and implants treated by surgeons who had inserted a minimum of 200 implants at the clinic were included. Kaplan-Meier curves were stratified with respect to the individual surgeon. A generalized estimating equation (GEE) method was used to account for the fact that repeated observations (several implants) were placed in a single patient. The factors bone quantity, bone quality, implant location, implant surface, and implant system were analyzed with descriptive statistics separately for each individual surgeon. Results: A total of 10 surgeons were eligible. The differences between the survival curves of each individual were statistically significant. The multivariate GEE model showed the following variables to be statistically significant: surgeon, bruxism, intake of antidepressants, location, implant length, and implant system. The surgeon with the highest absolute number of failures was also the one who inserted the most implants in sites of poor bone and used turned implants in most cases, whereas the surgeon with the lowest absolute number of failures used mainly modern implants. Separate survival analyses of turned and modern implants stratified for the individual surgeon showed statistically significant differences in cumulative survival. Conclusion: Different levels of failure incidence could be observed between the surgeons, occasionally reaching significant levels. Although a direct causal relationship could not be ascertained, the results of the present study suggest that the surgeons' technique, skills, and/or judgment may negatively influence implant survival rates. Int J Prosthodont 2017 (10 pages). doi: 10.11607/ijp.5151

$Research paper thumbnail of Factors influencing the fracture of dental implants$

BACKGROUND: Implant fractures are rare but offer a challenging clinical situation. PURPOSE: To de... more BACKGROUND: Implant fractures are rare but offer a challenging clinical situation. PURPOSE: To determine the prevalence of implant fracture and the possible risk factors predisposing an implant to a higher fracture risk. MATERIALS AND METHODS: This retrospective study is based on 2670 patients consecutively treated with implant-supported prostheses. Anatomical-, patient-, and implant-related factors were collected. Descriptive statistics and survival analyses were performed. Generalized estimating equations (GEE) evaluated the effect of explanatory variables on implant fracture. RESULTS: Forty-four implants (out of 10 099; 0.44%) fractured. The mean ± standard deviation time for fracture to occur was 95.1 ± 58.5 months (min-max, 3.8-294.7). Half of the occurrences of fracture happened between 2 and 8 years after implantation. Five factors had a statistically significant influence on the fracture of implants (increase/decrease in fracture probability): use of higher grades of titanium (decrease 72.9%), bruxism (increase 1819.5%), direct adjacency to cantilever (increase 247.6%), every 1 mm increase in implant length (increase 22.3%), every 1 mm increase in implant diameter (decrease 96.9%). CONCLUSIONS: It is suggested that 5 factors could influence the incidence of implant fractures: grade of titanium, implant diameter and length, cantilever, bruxism.

BACKGROUND: Very long-term follow-up of oral implants is seldom reported in the literature. PURPO... more BACKGROUND: Very long-term follow-up of oral implants is seldom reported in the literature. PURPOSE: To assess oral implant failure rates and marginal bone loss (MBL) of patients followed up for a minimum of 20 years. MATERIALS AND METHODS: Implants placed in patients followed up for 20+ years were included. Descriptive statistics, survival analyses, generalized estimating equations were performed. Three-hundred implants were randomly selected for MBL. RESULTS: 1,045 implants (227 patients) were included. Implant location, irradiation, and bruxism affected the implant survival rate. Thirty-five percent of the failures occurred within the first year after implantation, and another 26.8% in the second/third year. There was a cumulative survival rate of 87.8% after 36 years of follow-up. In the last radiological follow up, 35 implants (11.7%) had bone gain, and 35 implants (11.7%) presented at least 3 mm of MBL. Twenty-six out of 86 failed implants with available radiograms presented severe MBL in the last radiological register before implant failure. CONCLUSIONS: Most of the implant failures occurred at the first few years after implantation, regardless of a very long follow up. MBL can be insignificant in long-term observations, but it may, nevertheless, be the cause of secondary failure of oral implants in some cases.

BACKGROUND: Some studies indicated that implant failures are commonly concentrated in few patient... more BACKGROUND: Some studies indicated that implant failures are commonly concentrated in few patients. PURPOSE: To identify and analyze cluster behavior of dental implant failures among subjects of a retrospective study. MATERIALS AND METHODS: This retrospective study included patients receiving at least three implants only. Patients presenting at least three implant failures were classified as presenting a cluster behavior. Univariate and multivariate logistic regression models and generalized estimating equations analysis evaluated the effect of explanatory variables on the cluster behavior. RESULTS: There were 1406 patients with three or more implants (8337 implants, 592 failures). Sixty-seven (4.77%) patients presented cluster behavior, with 56.8% of all implant failures. The intake of antidepressants and bruxism were identified as potential negative factors exerting a statistically significant influence on a cluster behavior at the patient-level. The negative factors at the implant-level were turned implants, short implants, poor bone quality, age of the patient, the intake of medicaments to reduce the acid gastric production, smoking, and bruxism. CONCLUSIONS: A cluster pattern among patients with implant failure is highly probable. Factors of interest as predictors for implant failures could be a number of systemic and local factors, although a direct causal relationship cannot be ascertained.

Is the intake of selective serotonin reuptake inhibitors associated with an increased risk of den... more Is the intake of selective serotonin reuptake inhibitors associated with an increased risk of dental implant failure?. Int. Abstract. The aim of this retrospective study was to investigate the association between the intake of selective serotonin reuptake inhibitors (SSRIs) and the risk of dental implant failure. Patients were included if they were taking SSRIs only and no other medication, did not present any other systemic condition or compromising habits (bruxism, smoking, snuff), and complied with the use of prophylactic antibiotics for implant surgery. The multivariate generalized estimating equation (GEE) method and multilevel mixed-effects parametric survival analysis were used to test the association between SSRI exposure (predictor variable) and the risk of implant failure (outcome variable), adjusting for several potential confounders (other variables). The total number of implants with information available and meeting the necessary eligibility criteria was 931 (35 failures). These were placed in 300 patients. The implant failure rate was 12.5% for SSRI users and 3.3% for non-users (P = 0.007). Kaplan–Meier analysis showed a statistically significant difference in the cumulative survival rate (P < 0.001). The multivariate GEE model did not show a statistically significant association between SSRI intake and implant failure (P = 0.530), nor did the multilevel model (P = 0.125). It is suggested that the intake of SSRIs may not be associated with an increased risk of dental implant failure.

Purpose: To investigate the association between the intake of proton pump inhibitors (PPIs) and t... more Purpose: To investigate the association between the intake of proton pump inhibitors (PPIs) and the risk of dental implant failure. Materials and Methods: The present retrospective cohort study is based on patients consecutively treated between 1980 and 2014 with implant-supported/retained prostheses at one specialist clinic. Modern endosseous dental implants with cylindrical or conical design were included, and only complete cases were considered; ie, only those implants with information available for all variables measured were included in the regression model analysis. Zygomatic implants and implants detected in radiographies but without basic information about them in the patients' files were excluded from the study. Implant-and patient-related data were collected. Multilevel mixed-effects parametric survival analysis was used to test the association between PPI exposure (predictor variable) and risk of implant failure (outcome variable), adjusting for several potential confounders. Results: A total of 3,559 implants were placed in 999 patients, with 178 implants reported as failures. The implant failure rates were 12.0% (30/250) for PPI users and 4.5% (148/3,309) for nonusers. A total of 45 out of 178 (25.3%) failed implants were lost up to abutment connection (6 in PPI users, 39 in nonusers), with an early-to-late failure ratio of 0.34:1. The intake of PPIs was shown to have a statistically significant negative effect for implant survival rate (HR 2.811; 95% CI: 1.139 to 6.937; P = .025). Bruxism, smoking, implant length, prophylactic antibiotic regimen, and implant location were also identified as factors with a statistically significant effect on the implant survival rate. Conclusion: This study suggests that the intake of PPIs may be associated with an increased risk of dental implant failure. Int J Oral MaxIllOfac IMplants 2017 (6 pages). doi: 10.11607/jomi.5662 Keywords: dental implant, failure, multilevel mixed effects parametric survival analysis, multivariate analysis, proton pump inhibitors, risk factors

Osseointegration was discovered in 1962 and coined as a term in 1977. Original definitions implie... more Osseointegration was discovered in 1962 and coined as a term in 1977. Original definitions implied direct contact between foreign materials and bone without any interposed soft tissue layers. Today, osseointegration is regarded to be a foreign body response to separate foreign elements from bone. A new definition of the term is suggested in this paper; " Osseointegration is a foreign body reaction where interfacial bone is formed as a defense reaction to shield off the implant from the tissues ". Excellent clinical results of osseointegrated implants have been reported from dentistry and Ear Nose Throat surgery, the latter with the indications of a stable anchorage of hearing aids or facial epistheses in cases of facial trauma. In Orthopaedic surgery a randomized controlled clinical trial has been undertaken demonstrating very good clinical results supported by positive radiostereo-photogrammetical data.

Purpose: To integrate the available data published to date on ameloblastic fibromas (AF) and amel... more Purpose: To integrate the available data published to date on ameloblastic fibromas (AF) and ameloblastic fibrosarcomas (AFS) into a comprehensive analysis of their clinical/radiological features. Methods: An electronic search was undertaken in July 2017. Eligibility criteria included publications having enough clinical, radiological and histological information to confirm a definite diagnosis. Results: A total of 244 publications (279 central AF tumours, 10 peripheral AF, 103 AFS) were included. AF and AFS differed significantly with regard to the occurrence of patients' mean age, bone expansion, cortical bone perforation and lesion size. Recurrence rates were as follows: central AF (19.2%), peripheral AF (12.5%), AFS (all lesions, 35%), primary (de novo) AFS (28.8%) and secondary AFS (occurring after an AF, 50%). Larger lesions and older patients were more often treated by surgical resections for central AF. Segmental resection resulted in the lowest rate of recurrence for most of the lesion types. AFS treated by segmental resection had a 70.5% lower probability to recur (OR 0.295; P = .049) than marginal resection; 21.3% of the AFS patients died due to complications related to the lesion. Conclusions: Very long follow-up is recommended for AF lesions, due to the risk of recurrence and malignant change into AFS. Segmental resection is the most recommended therapy for AFS.

Purpose: The aim of this study was to integrate the available data published on calcifying epithe... more Purpose: The aim of this study was to integrate the available data published on calcifying epithelial odontogenic tumors (CEOT) into a comprehensive analysis of its clinical and radiologic features. Materials and methods: An electronic search was undertaken in May 2016. Eligibility criteria were publications having enough clinical, radiological and/or histological information to confirm definite diagnosis. Results: A total of 362 lesions were found, 339 with enough information were analyzed. Variants clear cells (n ¼ 33) and Langerhans cells (n ¼ 10) were rarely described in the literature, as well as lesions with malignant transformation (n ¼ 8). Central lesions (n ¼ 264) were more prevalent than their peripheral counterparts (n ¼ 24). A higher prevalence characterized the mandible, posterior region, and third and fourth decades. About 40% of the peripheral lesions showed signs of underlying bone erosion, and about half of the central ones showed signs of cortical bone perforation. Recurrence was found in all lesions (12.6%), peripheral lesions (18.8%), central lesions (11.6%), clear cell (10.7%), Langerhans cell (0%), and those with malignant transformation (42.9%). Excision or curettage was associated with the highest recurrence rate. None of the variables showed a statistically significant influence on the recurrence rate. Conclusions: The possible locally aggressive behavior of the lesions recommends a less conservative management than simple curettage. The clear cell variant shows similar demographic data and biological behavior compared to the non-variant lesions, suggesting that the presence of clear cells does not have an important clinical significance.

PURPOSE: To integrate the available data published on ameloblastic fibrodentinoma (AFD) and amelo... more PURPOSE: To integrate the available data published on ameloblastic fibrodentinoma (AFD) and ameloblastic fibro-odontoma (AFO) into a comprehensive analysis of its clinical and radiologic features. MATERIALS AND METHODS: An electronic search was undertaken in August 2016. Eligibility criteria included publications reporting cases of AFD or AFO with enough clinical, radiologic, and histologic information to confirm the diagnosis. Demographic data, lesion site and size, treatment approach, and recurrence were analyzed and compared between AFD and AFO. RESULTS: Fifty-four publications reporting on 64 AFDs (60 central, 4 peripheral) and 137 publications reporting on 215 AFOs (211 central, 3 peripheral, 1 unknown) were included. The difference in recurrence rate (when the information about recurrence was provided) was not statistically relevant. The mean age of patients affected by AFD was not statistically different from that of patients affected by AFO. CONCLUSIONS: AFD and AFO presented several similarities: higher prevalence in men and in the mandibles, similar mean age of patients, rate of cortical bone perforation and of the lesions' association with displaced or unerupted teeth and tooth root resorption, mean lesion size, and recurrence rate. The lesions differed in the presence of radiopacities and locularity. Taken together, these data do not support the concept of progressive maturation of these tumoral conditions.

OBJECTIVE: To integrate the available data published on glandular odontogenic cyst (GOC) into a c... more OBJECTIVE: To integrate the available data published on glandular odontogenic cyst (GOC) into a comprehensive analysis of its clinical/radiological and histopathological features. METHODS: An electronic search was undertaken in May/2017. Eligibility criteria included publications having enough clinical/radiological/histological information to confirm the diagnosis. RESULTS: Fifty-eight publications (169 GOCs) were included. The lesion was slightly more prevalent in men than in women. There was a high prevalence in the fifty/sixth decades of life, in the anterior regions, and in mandibles. Lesions were commonly associated with bone expansion (73%) and unilocular radiological appearance (61.5%). GOC was found to be associated with tooth displacement or an unerupted tooth (30.9%), cortical bone perforation (26%), presence of clinical symptoms (24.3%), root resorption (13.9%). Microscopic parameters most commonly were observed in GOCs-in at least 95% of the lesions: presence of hobnail cells, intraepithelial microcysts, epithelial lining with variable thickness. The presence of apocrine snouting was the microscopic parameter less often found (40.4%). CONCLUSION: Although the recurrence rate of GOCs is not as high as previously believed, it is a relevant phenomenon (21.6%). Adjunctive procedures after enucleation should be considered. None of the clinical/radiological and histopathological features evaluated had a statistically significant effect on the recurrence rate.

Purpose: To investigate the recurrence rate of cementoblastomas for different variables aside fro... more Purpose: To investigate the recurrence rate of cementoblastomas for different variables aside from the clinical/radiologic features. Methods: An electronic search was undertaken in November/2016. Eligibility criteria included publications having enough clinical/radiological/histological information to confirm the diagnosis. Results: 141 publications (258 cementoblastomas) were included. There was an equal sex distribution. There was a high prevalence in the second/third decades of life, in the posterior regions, and in mandibular first molars. Lesions were commonly associated with bone expansion (74.9%), presence of clinical symptoms (70.2%), vital teeth (78%), root resorption (59.8%). Observations not as frequent: cortical bone perforation (16.3%), inferior displacement of the mandibular canal (23.6%). Treatment was reported for 229 cases. Twenty (11.8%) out of 170 recurred. Preservation of the involved teeth and location seem to not influence the recurrence rate, but there was a 687% higher probability (odds ratio 7.875; p ¼ 0.048) of recurrence for lesions associated with bone expansion, and a 217% higher probability (odds ratio 3.173; p ¼ 0.023) of recurrence for lesions presenting cortical bone perforation. Conclusions: Although the recurrence rate of cementoblastomas is not as high as previously believed, it is a relevant phenomenon (11.8%). The presence of bone expansion and cortical bone perforation seem to influence the recurrence rate.

Purpose: To investigate and compare the probability of recurrence of keratocystic odontogenic tum... more Purpose: To investigate and compare the probability of recurrence of keratocystic odontogenic tumors (KCOTs) for different variables and treatment protocols. Materials and methods: An electronic search was undertaken in April 2016 that included clinical series of KCOTs reporting recurrences. Untransformed proportions and meta-analyses were performed to estimate the probability/risk of recurrence, according to several variables. Results: A total of 94 publications were included (6427 KCOTs, 1464 recurrences). Probability of recurrence: all lesions, 21.1%; nevoid basal cell carcinoma syndrome, 35.4%; males, 20.3%; females, 19.3%; maxilla, 15.3%; mandible, 21.5%; unilocular, 14.7%; multilocular, 24.4%; marsupialization/ decompression, 28.7%; decompression þ enucleation ± additional therapy, 18.6%; enucleation/curet-tage, 22.5%; enucleation þ peripheral ostectomy, 18.6%; enucleation þ Carnoy's solution, 5.3%; enucleation þ cryotherapy, 20.9%; marginal/segmental resection, 2.2%. The recurrence was not statistically significantly affected by lesion location (maxilla vs. mandible, risk ratio [RR] 0.92, P ¼ 0.32) or patient's sex (male vs. female, RR 0.94, P ¼ 0.44), but by locularity (unilocular vs. multilocular, RR 0.67, P ¼ 0.007). Recurrence risk for surgical managements: marsupialization vs. enucleation (RR 1.65, P ¼ 0.0006), marsupialization vs. resection (RR 3.17, P ¼ 0.009), enucleation alone vs. enucleation þ peripheral ostectomy (RR 1.66, P ¼ 0.05), enucleation alone vs. enucleation þ Carnoy's solution (RR 1.94, P ¼ 0.03), enucleation alone vs. enucleation þ cryotherapy (RR 0.88, P ¼ 0.56). Conclusions: KCOTs have a considerable rate of recurrence, which varies significantly according to some clinical, radiographic, and histopathological features, as well as surgical management.

The aim of this meta-analysis was to test the null hypothesis of no difference in the implant fai... more The aim of this meta-analysis was to test the null hypothesis of no difference in the implant failure rates, marginal bone loss (MBL)and postoperative infection for patients being rehabilitated by turned versus anodised-surface implants, against the alternative hypothesis of a difference. An electronic search without time or language restrictions was undertaken in November 2015. Eligibility criteria included clinical human studies, either randomised or not. Thirty-eight publications were included. The results suggest a risk ratio of 2.82 (95% CI 1.95–4.06, P < 0.00001) for failure of turned implants, when compared to anodised-surface implants. Sensitivity analyses showed similar results when only the studies inserting implants in maxillae or mandibles were pooled. There were no statistically significant effects of turned implants on the MBL (mean difference-MD 0.02, 95%CI -0.16–0.20; P = 0.82) in comparison to anodised implants. The results of a meta-regression considering the follow-up period as a covariate suggested an increase of the MD with the increase in the follow-up time (MD increase 0.012 mm year 1), however, without a statistical significance (P = 0.813). Due to lack of satisfactory information, meta-analysis for the outcome ‘postoperative infection’ was not performed. The results have to be interpreted with caution due to the presence of several confounding factors in the included studies.

Objective: To assess the survival rate of craniofacial implants (CIs) to support facial prosthesi... more Objective: To assess the survival rate of craniofacial implants (CIs) to support facial prosthesis/epithesis and the prevalence of surgical/biological complications based on previously published studies. Methods: An electronic search was undertaken in March/2016. Only studies with a minimum of 5 patients were included. Untransformed proportions of implant failures for different regions were calculated. A meta-analysis evaluated the influence of radiotherapy on the failure rates. A meta-regression was performed considering the follow-up period as covariate. Results: Seventy publications included 2355 patients and 8184 CIs (545 failures). The probability of a failure was 5.5% for all CIs (95%CI 4.5-6.5, P < 0.001), 1.2% for CIs in the auricular region (95%CI 0.8-1.5, P < 0.001), 12.2% for the nasal region (95%CI 9.0-15.5, P = 0.017), and 12.1% for the orbital region (95%CI 9.3-15.0, P < 0.001). Radiotherapy statistically affected the CIs rates (OR 5.80, 95%CI 3.77-8.92, P < 0.00001). There was no statistically significant influence of the follow-up time on the proportion of implant failures (P = 0.814). Soft tissue adverse reactions were the most common complications. Conclusions: Implants placed in the auricular region have a lower probability of failure than those in the nasal and orbital regions. Soft tissue adverse reactions were the most common complications. Radio-therapy significantly affected the CIs failure rates.

Purpose: To assess the survival rate of zygomatic implants (ZIs) and the prevalence of complicati... more Purpose: To assess the survival rate of zygomatic implants (ZIs) and the prevalence of complications based on previously published studies. Materials and Methods: An electronic search of 3 databases was performed in December 2015 and was supplemented by manual searching. Clinical series of ZIs were included. Interval survival rate and cumulative survival rate (CSR) were calculated. The untransformed proportion of complications (sinusitis, soft tissue infection, paresthesia, oroantral fistulas) was calculated by considering the prevalence reported in the studies. Results: Sixty-eight studies were included, comprising 4,556 ZIs in 2,161 patients with 103 failures. The 12-year CSR was 95.21%. Most failures were detected within the 6-month postsurgical period. Studies (n = 26) that exclusively evaluated immediate loading showed a statistically lower ZI failure rate than studies (n = 34) evaluating delayed loading protocols (P = .003). Studies (n = 5) evaluating ZIs for the rehabilitation of patients after maxillary resections presented lower survival rates. The probability of presenting postoperative complications with ZIs was as follows: sinusitis, 2.4% (95% confidence interval [CI], 1.8-3.0); soft tissue infection, 2.0% (95% CI, 1.2-2.8); paresthesia, 1.0% (95% CI, 0.5-1.4); and oroantral fistulas, 0.4% (95% CI, 0.1-0.6). However, these numbers might be underestimated, because many studies failed to mention the prevalence of these complications. Conclusion: ZIs present a high 12-year CSR, with most failures occurring at the early stages postoperatively. The main observed complication related to ZIs was sinusitis, which can appear several years after ZI installation surgery.

Purpose: To integrate the available data published on peripheral calcifying cystic odontogenic tu... more Purpose: To integrate the available data published on peripheral calcifying cystic odontogenic tumour (CCOT) and peripheral dentinogenic ghost cell tumour (DGCT) into a comprehensive analysis of its clinical and radiologic features. Methods: An electronic search was undertaken in May, 2016. Eligibility criteria included publications reporting cases of peripheral CCOTs/DGCTs having enough clinical, radiological and histological information to confirm a definite diagnosis. Demographic data, lesion site and size, treatment approach and recurrence were analyzed. Results: Hundred and thirty-eight lesions were found (65 publications), and 117 lesions (63 publications) with enough information were analyzed (55 CCOTs, 50 DGCTs, 12 unknown). Mean age of patients was 51.3 ± 23.4 (min–max, 1–92), with higher mean age for the DGCTs variant. The lesions were more prevalent in the mandible, anterior region of the jaws, and in the second, sixth and eighth decades, with an equal sexual distribution. About 20% of all lesions showed signs of erosion of the underlying bone, with a higher rate for DGCTs. The mean lesion size was 1.3 ± 0.8 (min–max, 0.4–3.0). Time of follow-up was informed for 37 lesions, with a mean ± SD of 30.2 ± 21.0 months (min–max, 6–84). Almost all lesions were treated by conservative surgery; only three recurrences were reported. Conclusions: Peripheral CCOTs/DGCTs are rare lesions. Most of the lesions were treated by simple excision with or without curettage of the underlying bone. As the recurrence rate is very low, a conservative approach seems to be enough for the great majority of cases.

The aim of this study was to verify the presence, spatial location, and calibre of the accessory ... more The aim of this study was to verify the presence, spatial location, and calibre of the accessory canals (AC) of the canalis sinuosus by cone beam computed tomography, and their relationship to the anterior maxilla. This retrospective analysis included the scans of 1000 subjects. Parameters registered were sex, age, number of AC, presence or absence of AC with a diameter <1.0 mm, AC diameter (only for AC with a diameter >1.0 mm), and AC location in relation to the adjacent teeth. Males showed a statistically higher frequency of AC than females. The difference in age distribution was not statistically significant. Twenty percent of all AC presented a diameter of a least 1.0 mm. The end of the AC trajectory was most frequently located palatal to the anterior maxillary teeth. All relationships analyzed here were very weak (age vs. number of AC, age vs. AC diameter, number of AC vs. sex). Overall, the results of this study showed that AC of the canalis sinuosus are a common anatomical structure in the anterior maxilla, regardless of age and sex.

The purpose of the present study was to assess the influence of local and systemic factors on the... more The purpose of the present study was to assess the influence of local and systemic factors on the occurrence of dental implant failures up to the second-stage surgery (abutment connection). This retrospective study is based on 2,670 patients who received 10,096 implants and were consecutively treated with implant-supported prostheses between 1980 and 2014 at 1 specialist clinic. Several anatomic-, patient-, health-, and implant-related factors were collected. Descriptive statistics were used to describe the patients and implants. Univariate and multivariate logistic regression models were used at the patient level as well as the implant level to evaluate the effect of explanatory variables on the failure of implants up to abutment connection. A generalized estimating equation method was used for the implant-level analysis to account for the fact that repeated observations (several implants) were available for a single patient. Overall, 642 implants (6.36%) failed, of which 176 (1.74%) in 139 patients were lost up to second-stage surgery. The distribution of implants in sites of different bone quantities and qualities was quite similar between implants lost up to and after abutment connection. Smoking and the intake of antidepressants were the statistically significant predictors in the multivariate model (ClinicalTrials.gov NCT02369562).

Objectives: To analyze the complications of dental implant treatment in a group of patients with ... more Objectives: To analyze the complications of dental implant treatment in a group of patients with bruxism in comparison with a matched group of non-bruxers. Material and methods: Patients being diagnosed as bruxers were identified within a group of patients consecutively treated with implant-supported prostheses at one specialist clinic, based on the most recent listed sign and symptoms of bruxism according to the International Classification of Sleep Disorders. A diagnostic grading system of " possible, " " probable, " and " definite " sleep or awake bruxism was used, according to a recent published international consensus. A case–control matching model was used to match the bruxers with a group of non-bruxers, based on five variables. Implant-, prosthetic-, and patient-related data were collected, as well as 14 mechanical complications, and compared between groups. Results: Ninety-eight of 2670 patients were identified as bruxers. The odds ratio of implant failure in bruxers in relation to non-bruxers was 2.71 (95% CI 1.25, 5.88). Considering the same number of patients with the same total number of implants equally distributed between groups, the bruxers group had a higher prevalence of mechanical complications in comparison with the non-bruxers group. Conclusions: This study suggests that bruxism may significantly increase both the implant failure rate and the rate of mechanical and technical complications of implant-supported restorations.

$Research paper thumbnail of Factors influencing the fracture of dental implants$