Walter Bürgin

Comparison of periapical radiography and limited cone-beam tomography in posterior maxillary teeth referred for apical surgery

This study compared periapical (PA) radiography and cone-beam tomography (CBT) for preoperative diagnosis in posterior maxillary teeth of consecutive patients referred for possible apical surgery. Images were concurrently analyzed by an oral radiologist and an endodontist to reach consensus in interpretation of the radiographic findings. The final material included 37 premolars and 37 molars with a total of 156 roots. CBT showed significantly more lesions (34%, p < 0.001) than PA radiography. Detecting lesions with PA radiography alone was most difficult in second molars or in roots in close proximity to the maxillary sinus floor. Additional findings were seen significantly more frequently in CBT compared with PA radiography including expansion of lesions into the maxillary sinus (p < 0.001), sinus membrane thickening (p < 0.001), and missed canals (p < 0.05). The present study highlights the advantages of using CBT for preoperative treatment planning in maxillary posterior teeth with apical pathology.

Complication and Failure Rates with Implant‐Supported Fixed Dental Prostheses and Single Crowns: A 10‐Year Retrospective Study

PURPOSE Clinical studies related to the long-term outcomes with implant-supported reconstructions are still sparse. The aim of this 10-year retrospective study was to assess the rate of mechanical/technical complications and failures with implant supported fixed dental prostheses (FDPs) and single crowns (SCs) in a large cohort of partially edentulous patients. MATERIALS AND METHODS The comprehensive multidisciplinary examination consisted of a medical/dental history, clinical examination, and a radiographic analysis. Prosthodontic examination evaluated the implant-supported reconstructions for mechanical/technical complications and failures, occlusal analysis, presence/absence of attrition, and location, extension, and retention type. RESULTS Out of three hundred ninety seven fixed reconstructions in three hundred three patients, two hundred sixty eight were SCs and one hundred twenty seven were FDPs. Of these three hundred ninety seven implant-supported reconstructions, 18 had failed, yielding a failure rate of 4.5% and a survival rate of 95.5% after a mean observation period of 10.75 years (range: 8.4-13.5 years). The most frequent complication was ceramic chipping (20.31%) followed by occlusal screw loosening (2.57%) and loss of retention (2.06%). No occlusal screw fracture, one abutment loosening, and two abutment fractures were noted. This resulted in a total mechanical/technical complication rate of 24.7%. The prosthetic success rate over a mean follow-up time of 10.75 years was 70.8%. Generalized attrition and FDPs were associated with statistically significantly higher rates of ceramic fractures when compared with SCs. Cantilever extensions, screw retention, anterior versus posterior, and gender did not influence the chipping rate. CONCLUSIONS After a mean exposure time of 10.75 years, high survival rates for reconstructions supported by Sand-blasted Large-grit Acid-etched implants can be expected. Ceramic chipping was the most frequent complication and was increased in dentitions with attrition and in FDPs compared with SCs.

Does the mandible alter its functional position during activator treatment

The study aimed at revealing possible changes, in activator-free periods, in the positions and movements of the mandible induced by the wearing of an activator. Twenty-one children being treated with three different types of activator for the correction of Angle Class II, Division 1 malocclusion were studied. The movement capacity of the mandible, the rest position, and the position of tooth contact during chewing were recorded with a Sirognathograph before treatment and repeatedly during the first year of treatment. With the exception of a slight increase in the maximal protrusion, no changes in mandibular movement capacity were found. The anteroposterior position of the mandible in the rest position was constant during the period of treatment, but the freeway space increased. No changes in the position of the point of tooth contact during chewing were found. The study produced no evidence of a treatment-induced forward positioning of the mandible in activator-free periods.

Detection of dentinal cracks after root-end resection: an ex vivo study comparing microscopy and endoscopy with scanning electron microscopy

INTRODUCTION Dentinal cracks are occasionally observed at the cut root face after root-end resection in apical surgery. The objective of this ex vivo study was to evaluate and compare the efficiency of visual aids to identify root-end dentinal cracks. METHODS Twenty-six extracted human molars were decoronated, and the root canals were instrumented and filled. The apical 3 mm of the roots were resected, and the cut root faces were assessed with microscopy at x16 and x24 magnification and with endoscopy at x8 and x64 magnification (four visual aids). Roots were then duplicated for inspection with scanning electron microscopy. The presence, type, and location of cracks were registered by a blinded observer, with the scanning electron microcopy serving as the reference. The percentages of correct identification of dentinal cracks were then statistically compared among the four test configurations. RESULTS Endoscopy x64 showed the highest sensitivity for crack identification, irrespective of the applied methodology (ie, per root and per crack). However, higher scores of false-positive cracks (lower specificity) were found with endoscopy x64 than with the other tested visual aids. The correct detection and location of complete canal cracks (55.3%, 52.6%, 68.4%, and 78.9%) were higher than the detection of incomplete canal cracks (42.2%, 42.2%, 52.0%, and 64.7%) using the four tested visual aids (microscopy at x16 and x24 magnification and endoscopy at x8 and x64 magnification, respectively). Only one of five intradentin cracks was identified with endoscopy x64. CONCLUSIONS Overall, endoscopy x64 proved the most accurate visual aid for the identification of dentinal cracks after root-end resection in extracted human teeth; however, it also provided the most false identifications.

Implants with Original and Non-Original Abutment Connections

AIM To test in vitro the mechanical resistance, rotational misfit and failure mode of three original implant-abutment connections and to compare them to two connections between non-original abutments connected to one of the original implants. MATERIAL AND METHODS Three different implants with small diameters (3.3 mm for Straumann Roxolid, 3.5 mm for Nobel Biocare Replace and Astra Tech Osseospeed TX) were connected with individualized titanium abutments. Twelve implants from each system were connected to their original abutments (Straumann CARES, Nobel Biocare Procera, Astra Tech Atlantis). Twenty-four Roxolid implants were connected with non-original abutments using CAD/CAM procedures from the other two manufacturers (12 Nobel Biocare Procera and 12 Astra Tech Atlantis). For the critical bending test, a Zwick/Roell 1475 machine and the Xpert Zwick/Roell software were used. RESULTS The rotational misfit varied when comparing the different interfaces. The use of non-original grade V titanium abutments on Roxolid implants increased the force needed for deformation. The fracture mode was different with one of the original connections. CONCLUSIONS Non-original abutments differ in design of the connecting surfaces and material and demonstrate higher rotational misfit. These differences may result in unexpected failure modes.

Treatment Decisions in 330 Cases Referred for Apical Surgery

INTRODUCTION Apical surgery is an important treatment option for teeth with postendodontic apical periodontitis. However, little information is available regarding treatment planning in cases referred for apical surgery. This study evaluated the decisions made in such cases and analyzed the variables influencing the decision-making process. METHODS The study retrospectively assessed clinical and radiographic data of 330 teeth that had been referred to a specialist in apical surgery with regard to the treatment decisions made in those teeth. The clinical and radiographic variables were divided into subcategories to analyze which factors influenced the decision-making process. RESULTS The treatment decisions included apical surgery (59.1%), tooth extraction (25.8%), no treatment (9.1%), and nonsurgical endodontic retreatment (6.1%). Variables that showed statistically significant differences comparing treatment decisions among subcategories included probing depth (P = .001), clinical attachment level (P = .0001), tooth mobility (P = .012), pain (P = .014), clinical signs (P = .0001), length (P = .041) and quality (P = .026) of the root canal filling, and size (P = .0001) and location (P = .0001) of the periapical lesion. CONCLUSIONS This study shows that apical surgery was the most frequently made treatment decision in teeth referred to a specialist in apical surgery, but every fourth tooth was considered nonretainable and was scheduled for extraction. The data showed that the most common variables that influenced the decision to extract teeth were teeth with an increased probing depth and tooth mobility and teeth presenting with lesions not located at the apex.

Clinical course of chronic periodontitis: effect of lifelong light smoking (20 years) on loss of attachment and teeth

AIM To examine the lifelong effect of light smoking on periodontal health. METHODS The data were derived from a 20-year longitudinal study of a group of Norwegian, middle-class males. The patients were subset according to their smoking history. A total of 119 non-smokers and 17 smokers were examined, 20 years apart. RESULTS Current smokers had significantly higher plaque indices than non-smokers after the age of 35 years, while before 35 years, there was no difference. Before 20 years of age, the non-smokers exhibited greater gingival indices, but after the age of 35, the smokers had significantly more sites that bled upon probing. Smokers demonstrated higher mean calculus indices after 35 years and as they approached 50 years of age. At baseline, the two groups showed similar attachment loss (0.14 mm), but with increasing age and approaching 50 years, the attachment loss progressed significantly faster in smokers than in non-smokers (2.31 and 1.57 mm, respectively). Linear regression indicated that ageing and light smoking were independently and significantly related to attachment loss. CONCLUSIONS Lifelong light smoking could be confirmed as a risk factor for periodontal disease progression. However, in this population, smoking did not significantly increase the risk of tooth loss.

Clinical periodontal variables in patients with and without dementia—a systematic review and meta-analysis

BackgroundConsidering the increasing number of elderly people, dementia has gained an important role in today’s society. Although the contributing factors for dementia have not been fully understood, chronic periodontitis (CP) seems to have a possible link to dementia.AimTo conduct a systematic review including meta-analysis in order to assess potential differences in clinical periodontal variables between patients with dementia and non-demented individuals.MethodsThe following focused question was evaluated: is periodontitis associated with dementia? Electronic searches in two databases, MEDLINE and EMBASE, were conducted. Meta-analysis was performed with the collected data in order to find a statistically significant difference in clinical periodontal variables between the group of dementia and the cognitive normal controls.ResultsForty-two articles remained for full text reading. Finally, seven articles met the inclusion criteria and only five studies provided data suitable for meta-analysis. Periodontal probing depth (PPD), bleeding on probing (BOP), gingival bleeding index (GBI), clinical attachment level (CAL), and plaque index (PI) were included as periodontal variables in the meta-analysis. Each variable revealed a statistically significant difference between the groups. In an attempt to reveal an overall difference between the periodontal variables in dementia patients and non-demented individuals, the chosen variables were transformed into units that resulted in a statistically significant overall difference (p < 0.00001).ConclusionThe current findings indicate that compared to systemically healthy individuals, demented patients show significantly worse clinical periodontal variables. However, further epidemiological studies including a high numbers of participants, the use of exact definitions both for dementia and chronic periodontitis and adjusted for cofounders is warranted.Clinical relevanceThese findings appear to support the putative link between CP and dementia. Consequently, the need for periodontal screening and treatment of elderly demented people should be emphasized.

Trends of periodontal conditions in two different randomly selected Swiss (Bernese) cohorts 25 years apart

AIM To assess the periodontal conditions of two randomly selected Swiss cohorts 25 years apart. MATERIAL AND METHODS Standardized examinations were performed to assess the periodontal conditions of two randomly selected populations of the Canton of Bern; oral cleanliness was evaluated using the plaque index (PlI) and the retention index (RI). Gingival health was scored according to the gingival index (GI). Periodontal conditions were evaluated by pocket probing depth (PPD) and loss of attachment (LA). RESULTS At the first examination in 1985, 206 out of 350 subjects were evaluated, while in the second examination in 2010, 134 out of 490 subjects attended the examinations. In 1985, subjects showed a mean PlI of 1.16, and 0.77 in 2010. RI was 0.81 and 0.36 in 1985 and 2010 respectively. Mean GI was 1.34 and 0.6. The mean proportion of PPD ≤3 mm was 72% in 1985 and 97.3% in 2010. PPD ≥ 6 mm affected 2.0% in 1985 and 0.3% in 2010. In 1985, subjects had an average of 20.7 teeth, while in 2010, the average was 24.6. In 1985, 7.3% of the subjects were edentulous, while in 2010, 4.5% had no teeth. CONCLUSIONS Trends to improvements resulting in more teeth in function and better periodontal conditions were recognized.