Incidental findings in cone beam computed tomography (CBCT) scans for implant treatment planning: a retrospective study of 404 CBCT scans.

OBJECTIVES: To investigate the prevalence of incidental findings and need for further dental treatment and analyse the influence of size of field-of-view (FOV) and age in cone beam computed tomography (CBCT) for pre-implant planning. METHODS: 404 CBCT scans were examined retrospectively for incidental findings and need for further dental treatment. Incidental finding-frequencies and need for further treatment were assessed for different age (< 40 years, 40-60 years, > 60 years) and FOV groups (small, medium, large). Intraexaminer and interexaminer agreements were evaluated. RESULTS: In 82% of the scans at least one incidental finding was found, with a total of 766 overall. More incidental findings were found in scans with large FOV (98% vs. 72%, OR = 22.39 large vs. small FOV, p < 0.0001) and in scans of patients > 60 years (OR = 5.37 patient's age > 60 years vs. < 40 years, p = 0.0003). Further dental treatment due to incidental findings was needed in 31%. Scans with large FOV were more likely to entail further treatment (OR = 3.55 large vs. small FOV, p < 0.0001). Partial edentulism and large FOV were identified as risk factors for further treatment (p = 0.0003 and p < 0.0001). Further referral of the patient based on incidental findings was judged as indicated in 5%. Intra- and inter-examiner agreements were excellent (kappa = 0.944/0.805). CONCLUSIONS: A considerable number of incidental findings with need for further dental treatment was found in partially edentulous patients and in patients > 60 years. In pre-implant planning of elderly patients, the selection of large FOV CBCT scans, including dentoalveolar regions not X-rayed recently, help to detect therapeutically relevant incidental findings.

Inter- and intraindividual variability in virtual single-tooth implant positioning.

OBJECTIVES: The purpose of this prospective study was to determine the inter- and intraindividual variability in virtual single-tooth implant positioning based on the level of expertise, specialty, total time spent, and the use of a prosthetic tooth setup. MATERIALS AND METHODS: Virtual implant planning was performed on matched pre- and post-extraction intraoral scans (IOS), and cone-beam computed tomography scans of 15 patients. Twelve individual examiners, involving six novices and experts from oral surgery and prosthodontics positioned the implants, first based on anatomical landmarks utilizing only the post-extraction, and second with the use of the pre-extraction IOS as a setup. The time for implant positioning was recorded. After 1 month, all virtual plannings were performed again. The individual implant positions were superimposed to obtain 3D deviations using a software algorithm. RESULTS: An interindividual variability with mean angular, crestal, and apical positional deviations of 3.8 ± 1.94°, 1.11 ± 0.55, and 1.54 ± 0.66 mm, respectively, was found. When assessing intraindividual variability, deviations of 3.28 ± 1.99°, 0.78 ± 0.46, and 1.12 ± 0.61 mm, respectively, were observed. Implants planned by experts exhibited statistically lower deviations compared to those planned by novices. Longer planning times resulted in lower deviations in the experts' group but not in the novices. Oral surgeons demonstrated lower crestal, but not angular and apical deviations than prosthodontists. The use of a setup only led to minor adjustments. CONCLUSIONS: Substantial inter- and intraindividual variability exists during implant positioning utilizing specialized software planning. The level of expertise and the time invested influenced the deviations of the implant position during the planning sequence.

CBCTs in a Swiss university dental clinic: a retrospective evaluation over 5 years with emphasis on radiation protection criteria.

OBJECTIVES: To retrospectively evaluate all cone-beam computed tomography (CBCT) scans acquired from 2017 to 2022 in a Swiss university dental clinic with particular emphasis on radiation protection aspects. MATERIAL AND METHODS: Radiological databases at the dental clinic of the University of Bern, Switzerland, were explored using a self-developed search algorithm. Data of all acquired CBCT from 01.01.2017 to 27.06.2022 were screened. Exposure parameters (exposure time, exposure angle, milliampere (mA), kilovoltage (kV), field of view (FOV) size), dose area product (DAP), age, and sex of the patient were recorded anonymously. The collected data were analyzed mainly descriptively. Correlations measured the statistical relationships between the variables. RESULTS: A total of 10,348 CBCT datasets were analyzed. Patient age ranged from 5 to 96 years (mean: 49.4 years, SD: 21.6 years). The number of CBCTs in patients under 25 years was around 20% each year. In total, 10,313 (99.7%) CBCTs were acquired in small to medium FOV (FOV up to 10 cm of height), and 35 (0.3%) in large FOV (height > 10 cm). DAPs of small FOVs were 518.3 ± 233.2 mGycm2 (mean ± SD), of medium FOV 1233 ± 502.2 mGycm2, and of large FOV 2189 ± 368.7 mGycm2. DAP (ρ = 0.4048, p < 0.0001) and kV (ρ = 0.0210, p = 0.0327) correlated positively with age. Reduced scan angle correlated with young age (rpb 0.2729, p < 0.001). mA did not correlate with age (p = 0.3685). CONCLUSIONS: This study demonstrates that certain well-known radiation protection aspects as the reduction of FOV, mA, kV, and scan angle were only partly considered. CLINICAL RELEVANCE: Known radiation protection aspects, especially in young patients, should be fully applied in regular clinical practice.

[Re-osseointegration of a Dental Implant with Aseptic Loosening after Occlusal Correction: a Case Report]. / Aseptischer Verlust der Osseointegration von Implantaten ­ ist eine Reosseointegration möglich? Reosseointegration eines mobilen Implantates nach okklusaler Entlastung: ein Zufallsbefund.

The preservation of osseointegration is fundamental for the long-term success of dental implants. Breakdown of osseointegration may occur in cases of aseptic implant loosening, a poorly understood process leading to sudden implant failure. So far, no evidence-based therapy concept exists for implants with aseptic loosening. The present case report demonstrates the re-osseointegration of a dental implant in the mandible of a 79-year-old female patient with mamma carcinoma after loss of osseointegration caused by aseptic loosening. The only treatment performed was a correction of the occlusion. After a period of eight months, a re-osseointegration was observed clinically and radiographically, and remained stable for the follow-up period of 21 months. Reduction of occlusal forces after correction of the occlusion may have facilitated a re-osseointegration. Potential influences of concurrent antineoplastic chemotherapy regarding breast carcinoma or further unknown influences on implant re-osseointegration cannot be ruled out.

Interactions between the Tetrasodium Salts of EDTA and 1-Hydroxyethane 1,1-Diphosphonic Acid with Sodium Hypochlorite Irrigants.

INTRODUCTION: A clinically useful all-in-one endodontic irrigant with combined proteolytic and decalcifying properties is still elusive. In this study, the chemical effects of dissolving the tetrasodium salts of 1-hydroxyethane 1,1-diphosphonic acid (Na4HEDP) or Na4EDTA directly in sodium hypochlorite (NaOCl) irrigants in polypropylene syringes were assessed during the course of 1 hour. METHODS: The solubility of the salts in water was determined. Their compatibility with 1% and 5% NaOCl was measured by iodometric titration and in a calcium complexation experiment by using a Ca2+-selective electrode. RESULTS: The salts dissolved within 1 minute. The dissolution maximum of Na4HEDP in water (wt/total wt) was 44.6% ± 1.6%. The corresponding dissolution maximum of Na4EDTA was 38.2% ± 0.8%. Na4HEDP at 18% in 5% NaOCl caused a mere loss of 16% of the initially available chlorine during 1 hour. In contrast, a corresponding mixture between NaOCl and the Na4EDTA salt caused 95% reduction in available chlorine after 1 minute. Mixtures of 3% Na4EDTA with 1% NaOCl were more stable, but only for 30 minutes. Na4HEDP lost 24% of its calcium complexation capacity after 60 minutes. The corresponding loss for Na4EDTA was 34%. CONCLUSIONS: The compatibility and solubility of particulate Na4HEDP with/in NaOCl solutions are such that these components can be mixed and used for up to 1 hour. In contrast, short-term compatibility of the Na4EDTA salt with NaOCl solutions was considerably lower, decreasing at higher concentrations of either compound. Especially for Na4HEDP but also for Na4EDTA, the NaOCl had little effect on calcium complexation.