Multiple dental implant failures: A retrospective analysis of implant retention time and risk factors.

BACKGROUND: The present retrospective study investigates implant retention time in patients who had experienced multiple implant failures and explores possible risk factors. MATERIALS AND METHODS: Patients who underwent placement of at least two implants and experienced failure of two or more implants between 2004 and 2022 were included in the study population. Both patient- and implant-related risk factors, including age, sex, medical history, medication intake, smoking, alcohol consumption, implant properties and anatomical and surgical factors, were evaluated. Descriptive analysis and univariate and multivariate statistical analysis were performed to assess implant retention time and failure risk, with the level of statistical significance set at 0.05. RESULTS: A total of 371 patients (178 men and 193 women, median age 63 years) with 3,141 implants were included in the analysis (3.14% of all patients treated since 2004). Out of these implants, 1,090 failures were observed (59.01% of all failed implants at the Academy of Oral Implantology, Vienna, Austria), with a median retention time of 108.11 months. Patients who lost teeth due to periodontitis did not show a tendency towards early implant failure (P > 0.001). Nicotine consumption (P < 0.001), age < 50 years and > 70 years (P < 0.001), maxillary location (P = 0.05), transgingival healing (P < 0.001), no provisional restoration (P = 0.035) and short implant length (P < 0.001) were associated with statistically significantly shorter implant retention times. CONCLUSIONS: Patients with multiple implant failures displayed cluster behaviour and had a median implant retention time of 9 years. Smoking, short implant length, single-stage surgery and immediate loading were all associated with a higher risk of failure, whereas age between 50 and 70 years and tooth loss due to periodontitis were associated with a longer implant retention time.

Extra-short (< 7 mm) and extra-narrow diameter (< 3.5 mm) implants: a meta-analytic literature review.

AIM: To review available evidence in scientific literature on oral implants of severely reduced length or diameter. MATERIALS AND METHODS: Electronic and hand searches up to May 2017 were performed in order to identify clinical investigations providing implant survival and/or marginal bone resorption data for extra-short implants < 7.0 mm in length and extra-narrow implants < 3.5 mm in diameter (excluding one-piece mini-implants). RESULTS: A total of 2929 extra-short implants and 3048 extra-narrow diameter implants were investigated in 53 and 29 clinical studies, respectively. Shorter implants between 4.0 mm and 5.4 mm in length showed comparable results to implant lengths of 5.5 mm to 6.5 mm (95.1% vs. 96.4%, P = 0.121) and no difference regarding marginal bone resorption (0.7 mm vs 0.5 mm, P = 0.086). Implant lengths of 5.5 mm to 6.5 mm, however, performed significantly better in the mandible compared with the maxilla (P = 0.010). Smaller diameters between 3.0 mm and 3.25 mm yielded a significantly lower survival rate of 94.3% than wider implants of 3.3 mm to 3.4 mm diameter (97.7%, P < 0.001), while marginal bone resorption did not differ (0.4 mm vs 0.5 mm, P = 0.447). CONCLUSIONS: The results of the present literature review suggest that extra-short and extra-narrow-diameter implants show satisfactory survival rates of around 95% and little marginal bone resorption of around 0.5 mm after a mean follow-up of 3 years. However, implant lengths < 7 mm in the maxilla and < 5.5 mm in the mandible as well as diameters < 3.3 mm may increase early failure rates.

The frequency of dental abscesses increases in periods of low barometric pressure.

Bioclimatic conditions are thought to have an impact on the frequency of dental abscesses but previous studies have suffered from small patient cohorts, methodological obstacles, and restriction to a single site resulting in limited geographic and meteorological variability. The aim of the present study was to investigate the influence of environmental temperature and barometric pressure on the frequency of dental abscesses. Three maxillofacial and two dental clinics in Vienna retrospectively provided a total of 19,218 patients with dentoalveolar abscesses who were treated by intraoral incision between 1998 and 2011. Daily records from six local meteorological stations were consulted to assess daily meteorological parameters. Univariate and multivariate hurdle count regression models were fitted to estimate the effect of daily average barometric pressure and temperature on registered abscess frequencies. Temporal confounders causing variance of the observed abscess frequencies - such as weekday, business day, and month - were taken into consideration. On days of low barometric pressure a significant rise in dental abscess frequency was observed, even when adjusting for confounders. Environmental temperature, in contrast, did not show any effect. In conclusion, bioclimatic conditions affect health as low barometric pressure increases the number of patients with dental abscesses.

Effect of dental implants on bisphosphonate-related osteonecrosis of the jaws.

PURPOSE: Bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) is a side effect of BP therapy. Dental implants are believed to be a risk factor for developing BRONJ. In the present study, we analyzed the interval to the development of BRONJ in patients treated with BP who had received dental implants. PATIENTS AND METHODS: Patients with dental implants and established BRONJ were evaluated at the oral and maxillofacial surgery department (Medical University of Vienna). In addition, studies from 1978 to 2012 were included in a meta-analysis. Three groups were created: implantation before BP treatment, implantation after BP treatment, and implantation during BP treatment. The outcomes were evaluated using linear regression analysis. RESULTS: Patients who underwent dental implantation during (P < .001) and after (P < .001) treatment with BPs developed BRONJ more rapidly. The treatment duration with oral BPs was significantly related to the rapidity of developing BRONJ (P = .03). CONCLUSIONS: The insertion of dental implants during or after BP treatment accelerated the development of BRONJ. BRONJ occurred less frequently when the implants had been inserted before BP therapy had been started.

Bone morphogenetic proteins 2, 5, and 6 in combination stimulate osteoblasts but not osteoclasts in vitro.

Bone regeneration is required for fracture healing. Various procedures have been used to promote osteogenesis with bone morphogenetic proteins (BMPs). We assessed the effects of BMP-2, BMP-5, and BMP-6 in isolated and combined use on the generation of osteoblasts and osteoclasts by comparing the osteoclastic potency of each on osteoclasts of primary murine bone marrow cells. Subsequently, cells were stained for tartrate-resistant acid phosphatase, and real time PCR analysis of receptor activator of NKκB ligand and osteoprotegerin was conducted. The same combination of BMPs was used to assess their potential to enhance osteoblasts, employing a mineralization assay and real-time PCR analysis of collagen type-1, runx2, and osterix. While BMP-2 alone and the combination of BMP-2 and BMP-5 significantly enhanced osteoclastogenesis, BMP-2, BMP-5, and BMP-6 in combination did not have additional effects. However, the combined use of BMP-2, BMP-5, and BMP-6 had an additive effect on matrix mineralization and osterix expression in osteoblasts. Our study shows that the combination of BMP-2, BMP-5, and BMP-6 stimulates osteoblasts but not osteoclastogenesis. Thus, the synergistic use of various BMPs might improve effective bone regeneration in the clinical setting.

Preoperative radiochemotherapy in the treatment of advanced oral cancer: outcome of 276 patients.

INTRODUCTION: The aim of this study was to review survival and locoregional control in patients with advanced oral and oropharyngeal squamous cell carcinoma treated by multimodal therapy with preoperative radiochemotherapy and radical surgery. MATERIAL: Retrospective cohort study. METHODS: Included in this analysis are 276 consecutive patients with UICC disease stages III and IV (T2: 13.0%; T3: 16.7%; T4: 70.3%; N0: 29.7%; N1: 20.3%; N2: 45.3%; N3: 4.7%; stage III: 16.3%; stage IV: 83.7%). All patients received preoperative radiochemotherapy (50Gy, Mitomycin and 5-Fluorouracil) and radical locoregional resection. RESULTS: Median surveillance period was 101.4 months (24-202 months). 5-year overall survival probability was 53.9%. 5-year local control probability was 70.2%. CONCLUSION: These results underline the reliability of preoperative treatment of patients with oral and oropharyngeal cancer.

Preoperative chemoradiotherapy in the management of oral cancer: a review.

INTRODUCTION: Multi-modality treatment concepts involving preoperative radiotherapy (RT) or chemoradiotherapy (CRT) and subsequent radical resection are used much less frequently than postoperative treatment for oral and oropharyngeal squamous cell carcinomas. In some centres, however, the preoperative approach has been established for several years. MATERIAL: The present review is a compilation of the existing evidence on this subject. METHODS: In a literature-based meta-analysis, the survival data of 1927 patients from 32 eligible publications were analysed. RESULTS: The calculated survival rates of documented patients show remarkably good results with preoperative CRT and radical surgery. However, the findings of this analysis are based on data with a large proportion of studies using consecutive patient series. CONCLUSION: Hard evidence providing sufficient data from prospective randomised studies is as yet missing for preoperative CRT. Prospective randomised studies are mandatory in this area.

Mortality and causes of death after multimodality treatment for advanced oral and oropharyngeal cancer.

PURPOSE: To analyze mortality and causes of death in patients who received preoperative radiochemotherapy and underwent radical surgery for advanced oral or oropharyngeal cancer. PATIENTS AND METHODS: A total of 222 patients who underwent multimodality treatment from 1990 to 2000 were included in the study. The inclusion criterion was International Union Against Cancer (UICC) disease stage II to IV (T2, 33.3%; T3, 12.6%; T4, 54.1%). Patients received preoperative radiotherapy 50 Gy and concomitant chemotherapy with mitomycin and 5-fluorouracil. Radical local-regional en bloc resection was performed in all patients. Survival status and causes of death were ascertained from the National Health Registry. Death certificates and autopsy reports were consulted when hospital files failed to provide reliable data. RESULTS: After a median surveillance period of 72.3 months (range, 24 to 152 months), 59% of patients were alive, 21% had died of recurrence, 5% had died perioperatively, and 15% had died from other causes. Of these, a second cancer in the head and neck region or the lower respiratory tract or the upper digestive tract was found in 7.3%. Although 93% of deaths related to recurrent disease occurred within the first 36 months after surgery, the remaining causes of death did not reveal a specific temporal pattern. CONCLUSION: Favorable survival data were registered for patients with advanced squamous cell carcinoma of the oral cavity who underwent combined treatment protocols. These patients frequently die of comorbidities. Because recurrent disease is a less common cause of mortality than are other causes, the latter should receive attention during surveillance.

Influence of previous radiotherapy on free tissue transfer in the head and neck region: evaluation of 455 cases.

OBJECTIVE/HYPOTHESIS: The aim of this retrospective cohort study was to investigate the effect of prior radiotherapy (XRT) on the outcome of microvascular free tissue transfer in the head and neck region. METHODS: Four hundred fifty-five patients, subdivided into three groups, were analyzed. Groups I (no previous XRT, n=110), II (previous radiochemotherapy with 50 Gy focus dosage in the primary treatment regime for oral cancer, n=322), and III (secondary reconstruction after XRT-induced complications, n=23) were compared regarding flap success rate, postoperative complications, postoperative mortality, duration of intensive care (DOIC), and hospitalization (DOH). RESULTS: Flap success did not differ significantly across groups (I: 95.5%, II: 93.2%, III: 91.3%. Risk of postoperative complications was significantly lower for group I (12.7%) compared with groups II (23.9%) and III (39.1%). DOIC and DOH were significantly shorter for patients in group I than for those in groups II and III. CONCLUSIONS: XRT before free tissue transfer does not significantly increase flap loss or postoperative mortality but does increase postoperative complications and length of hospitalization.

Experience with microvascular free flaps in preoperatively irradiated tissue of the oral cavity and oropharynx in 303 patients.

This study examined free flap reconstruction of surgical defects of the oral cavity and oropharynx after preoperative radiochemotherapy. Included in this analysis are 303 prospectively followed patients who underwent a multimodal treatment regime for advanced oral and oropharyngeal carcinoma. All patients received preoperative radiochemotherapy (Mitomycin C, 5-FU, 50 Gy), ablative surgery, and primary free flap reconstruction. Patient characteristics, surgical parameters like duration of surgery and ischaemia, size of defect, type of transplant, and clinical outcome parameters like duration of intensive care and hospitalization, type of complications, necessity and type of revision surgery were statistically evaluated. Overall flap success rate was 93.1%. Sixty seven patients required revision and 21 flaps (6.9%) were lost. Overall complication rate was 22.1%. Mean duration of intensive care (DOIC) and duration of overall postoperative hospitalization (DOH) were 11.0+/-9.6 days and 35.9+/-26.3 days, respectively. Flap success and flap related complications after 50 Gy focal radiation dosage were found in a comparable range as in published series of reconstructions in uncompromised tissue.

Neoadjuvant radiochemotherapy of oral cavity and oropharyngeal cancer: evaluation of tumor response by CT differs from histopathologic response assessment in a significant fraction of patients.

BACKGROUND: Our aim was to compare and assess the predictive value of CT and histopathologic grading of tumor regression at primary tumor sites in patients with squamous cell carcinoma of the oral cavity and oropharynx after neoadjuvant (preoperative) radiochemotherapy (RCT). METHODS: We investigated 55 patients with carcinomas of the oral cavity and oropharynx who underwent RCT before curative surgery. Two blinded observers measured RCT-induced reduction of tumor volume in pretherapeutic and posttherapeutic CT scans. Volume changes were compared with histopathologic findings obtained at surgery. RESULTS: Histopathologic response evaluation revealed 31 complete remissions, 12 cases of partial response, and 12 nonresponders. We performed a logistic regression analysis to evaluate whether measured volume reduction could predict the likelihood of belonging to a certain response group. Taken together, we found 35 correct, 12 false-negative, and seven false-positive predictions. CONCLUSIONS: The extent of remission as assessed by CT scans 4 to 5 weeks after completion of neoadjuvant RCT leads to false predictions in a significant percentage of patients.

Cross-sectional and functional imaging of the temporomandibular joint: radiology, pathology, and basic biomechanics of the jaw.

The temporomandibular joint (TMJ) is a common site of complaint. Clicking sounds and pain are indicators of a frequent condition called internal derangement, most often affecting females. As a general term, internal derangement describes a structural abnormality within an articulation. The internal derangement of the TMJ is a specific term defined as an abnormal positional and functional relationship between the disk and articulating surfaces. Imaging of the joint is an important element in the diagnostic work-up. Trauma and inflammatory arthritis account for most of the other TMJ problems. A thorough understanding of joint anatomy and normal function is a prerequisite for perceiving abnormalities and making the correct diagnosis. The authors elucidate joint anatomy, correlating cadaveric specimen and anatomic slices with conventional and cross-sectional imaging studies. TMJ biomechanics are illustrated with schematics and animations, and an overview of imaging strategies and techniques is presented. Common abnormalities are described and illustrated, and a brief discussion of therapeutic options is included.