Simone F.M. Janner

Characteristics and dimensions of the Schneiderian membrane: a radiographic analysis using cone beam computed tomography in patients referred for dental implant surgery in the posterior maxilla.

OBJECTIVES To determine the dimensions of the Schneiderian membrane using limited cone beam computed tomography (CBCT) in individuals referred for dental implant surgery, and to determine factors influencing the mucosal thickness. MATERIAL AND METHODS The study included 143 consecutive patients referred for dental implant placement in the posterior maxilla. A total of 168 CBCT images were taken using a limited field of view of 4 × 4 cm, 6 × 6 cm, or 8 × 8 cm. Reformatted coronal CBCT slices were analyzed with regard to the thickness and characteristics of the Schneiderian membrane in nine standardized points of reference. Factors such as age, gender, or status of the remaining dentition that could influence the dimensions of the Schneiderian membrane were evaluated using univariate and multivariate linear regression models. RESULTS The thickness of the Schneiderian membrane exhibited a wide range, with a minimum value of 0.16 mm and a maximum value of 34.61 mm. The highest mean values, ranging from 2.16 to 3.11 mm, were found for the mucosa located in the mid-sagittal regions of the maxillary sinus. The most frequent mucosal findings diagnosed were flat thickenings of the Schneiderian membrane (62 positive findings, 37%). For the multivariate linear regression model, only gender had a statistically significant influence on the mean overall and mid-sagittal thickness of the sinus mucosa. CONCLUSION There is great interindividual variability in the thickness of the Schneiderian membrane. Gender seems to be the most important parameter influencing mucosal thickness in asymptomatic patients. Future studies are needed to assess the therapeutic and prognostic consequences of mucosal alterations in the maxillary sinus.

Characteristics and dimensions of the Schneiderian membrane and apical bone in maxillary molars referred for apical surgery: a comparative radiographic analysis using limited cone beam computed tomography.

INTRODUCTION The purpose of the present study was to evaluate the thickness and the anatomic characteristics of the Schneiderian membrane and cortical bone using limited cone beam computed tomography (CBCT) scannning in patients referred for planning of apical surgery of maxillary molars. METHODS This controlled study included 2 cohorts of patients (n = 50 for each group). For patients in group 1 (with apical pathology), 3 measurements in millimeters were performed using coronal and sagittal CBCT slices: the dimension of the apical lesion in the axis of the root, the width of the cortical bone in the axis of the root, and the thickness of the Schneiderian membrane perpendicular to the underlying cortical bone. For the analysis of CBCT scans of group 2 (without apical pathologies), 2 measurements were performed using coronal and sagittal CBCT slices: the width of the cortical bone in the axis of the root and the thickness of the Schneiderian membrane perpendicular to the underlying cortical bone. RESULTS For group 1, the periapical lesions evaluated measured between 0.27 and 7.41 mm in diameter, the apical bone separating the apical lesions from the maxillary sinus ranged from 0.13 to 7.83 mm, and the dimensions of the Schneiderian membrane ranged from 0.25 to 13.98 mm. The apical bone was generally thicker in patients with periapical lesions. Regarding the dimensions of the Schneiderian membrane, the values were statistically significantly higher for the patients in group 1 compared with group 2. CONCLUSIONS The study showed that the Schneiderian membrane in the vicinity of roots with apical lesions tends to be significantly thicker when compared with the roots of teeth without apical pathoses.

Precision of endodontic working length measurements: a pilot investigation comparing cone-beam computed tomography scanning with standard measurement techniques

INTRODUCTION The objective of this pilot investigation was to evaluate the utility and precision of already existing limited cone-beam computed tomography (CBCT) scans in measuring the endodontic working length, and to compare it with standard clinical procedures. METHODS Three patients referred to the department received limited CBCT scans for diagnostics and preoperative treatment planning of cystic jawbone pathologies. Part of the therapy consisted of root canal treatments before surgical enucleation of the lesion. For the determination of the working length, the root canal length was measured with an electronic apex locator (EAL) by the endodontist. This measurement was compared with the root canal length as measured on the respective CBCT scans by an examiner not involved in the endodontic treatment. The interrater agreement between the two examiners was analyzed to determine the feasibility of this technique. RESULTS In the three included patients, 9 teeth with a total of 10 root canals were treated. For these canals, a strong correlation was found between the endodontic working length as measured in the CBCT images and the EAL measurements (Pearson correlation coefficient ranging from 0.904 to 0.968). CONCLUSIONS Based on the present findings, an already existing CBCT scan of teeth to be endodontically treated can be useful to determine the endodontic working length in combination with clinical measurements such as the EAL. Future prospective studies should evaluate if and when intraoral radiography for measuring the length of root canals can be avoided when CBCT images are available.

Endodontic Working Length Measurement with Preexisting Cone-Beam Computed Tomography Scanning: A Prospective, Controlled Clinical Study

INTRODUCTION The determination of root canal length is a significant outcome predictor for endodontic treatments. The aim of this prospective, controlled clinical study was to analyze endodontic working length measurements in preexisting cone-beam computed tomography (CBCT) scans and to compare them with clinical root canal length determination by using an electronic apex locator (EAL). METHODS All included patients had received a CBCT scan independent of the present study and needed root canal treatment of at least 1 anterior tooth visible in the field of view. Clinically, the root canal length was measured with an EAL by an endodontist. This measurement was compared with the root canal length as measured on vestibulo-oral and mesiodistal CBCT sections by an examiner not involved in the endodontic treatment. The CBCT measurements were repeated once for analysis of intrarater reliability. RESULTS Forty anterior teeth in 30 patients (13 women and 17 men; average age, 44 years; range, 18-80 years) were included in this investigation. The Pearson correlation coefficient (r) comparing the root canal length measurements by using CBCT and EAL was 0.97. In addition, high intrarater reliability for the CBCT measurements was found (r = 0.99). CONCLUSIONS This prospective, controlled clinical study showed that limited CBCT scans can be used for endodontic working length measurements. Future studies are needed to evaluate whether preexisting CBCT scans could replace initial periapical radiographs and working length periapical radiographs.

Implant therapy in a surgical specialty clinic: an analysis of patients, indications, surgical procedures, risk factors, and early failures.

PURPOSE The aim of this study was to analyze the patient pool referred to a specialty clinic for implant surgery over a 3-year period. MATERIALS AND METHODS All patients receiving dental implants between 2008 and 2010 at the Department of Oral Surgery and Stomatology were included in the study. As primary outcome parameters, the patients were analyzed according to the following criteria: age, sex, systemic diseases, and indication for therapy. For the inserted implants, the type of surgical procedure, the types of implants placed, postsurgical complications, and early failures were recorded. A logistic regression analysis was performed to identify possible local and systemic risk factors for complications. As a secondary outcome, data regarding demographics and surgical procedures were compared with the findings of a historic study group (2002 to 2004). RESULTS A total of 1,568 patients (792 women and 776 men; mean age, 52.6 years) received 2,279 implants. The most frequent indication was a single-tooth gap (52.8%). Augmentative procedures were performed in 60% of the cases. Tissue-level implants (72.1%) were more frequently used than bone-level implants (27.9%). Regarding dimensions of the implants, a diameter of 4.1 mm (59.7%) and a length of 10 mm (55.0%) were most often utilized. An early failure rate of 0.6% was recorded (13 implants). Patients were older and received more implants in the maxilla, and the complexity of surgical interventions had increased when compared to the patient pool of 2002 to 2004. CONCLUSION Implant therapy performed in a surgical specialty clinic utilizing strict patient selection and evidence-based surgical protocols showed a very low early failure rate of 0.6%.

Influence of Particle Size of Deproteinized Bovine Bone Mineral on New Bone Formation and Implant Stability after Simultaneous Sinus Floor Elevation: A Histomorphometric Study in Minipigs

BACKGROUND Deproteinized bovine bone mineral (DBBM) is one of the best-documented bone substitute materials for sinus floor elevation (SFE). PURPOSE DBBM is available in two particle sizes. Large particles are believed to facilitate improved neoangiogenesis compared with small ones. However, their impact on the rate of new bone formation, osteoconduction, and DBBM degradation has never been reported. In addition, the implant stability quotient (ISQ) has never been correlated to bone-to-implant contact (BIC) after SFE with simultaneous implant placement. MATERIALS AND METHODS Bilateral SFE with simultaneous implant placement was performed in 10 Göttingen minipigs. The two sides were randomized to receive large or small particle size DBBM. Two groups of 5 minipigs healed for 6 and 12 weeks, respectively. ISQ was recorded immediately after implant placement and at sacrifice. Qualitative histological differences were described and bone formation, DBBM degradation, BIC and bone-to-DBBM contact (osteoconduction) were quantified histomorphometrically. RESULTS DBBM particle size had no qualitative or quantitative impact on the amount of newly formed bone, DBBM degradation, or BIC for either of the healing periods (p > 0.05). Small-size DBBM showed higher osteoconduction after 6 weeks than large-size DBBM (p < 0.001). After 12 weeks this difference was compensated. There was no significant correlation between BIC and ISQ. CONCLUSION Small and large particle sizes were equally predictable when DBBM was used for SFE with simultaneous implant placement.

Indications and Frequency for the Use of Cone Beam Computed Tomography for Implant Treatment Planning in a Specialty Clinic.

PURPOSE To analyze the indications and frequency for three-dimensional (3D) imaging for implant treatment planning in a pool of patients referred to a specialty clinic over a 3-year period. MATERIALS AND METHODS All patients who received dental implants between 2008 and 2010 at the Department of Oral Surgery and Stomatology at the University of Bern were included in the study. The influence of age, gender, and time of treatment (2008 to 2010) on the frequency of use of two-dimensional (2D) radiographic imaging modalities alone or in combination with 3D cone beam computed tomography (CBCT) scans was analyzed. Furthermore, the influence of the indication, location, and need for bone augmentation on the frequency of use of 2D imaging modalities alone or in combination with CBCT was evaluated. RESULTS In all, 1,568 patients (792 women and 776 men) received 2,279 implants. Overall, 633 patients (40.4%) were analyzed with 2D imaging procedures alone. CBCT was performed in 935 patients (59.6%). There was a statistically significant increase in CBCT between 2008 and 2010. Patients older than 55 years received a CBCT scan in addition to 2D radiographic imaging statistically significantly more often. Additional 3D imaging was most frequently performed in the posterior maxilla, whereas 2D radiographs alone exhibited the highest frequency in the anterior mandible. The combination of 2D with CBCT was used predominantly for implant placement with simultaneous or staged guided bone regeneration or sinus elevation. CONCLUSION Based on these findings from a specialty clinic, the use of additional CBCT imaging for implant treatment planning is influenced by the indication, location, local anatomy (including the need for bone augmentation), and the age of the patient.

Scarring of Soft Tissues Following Apical Surgery: Visual Assessment of Outcomes One Year After Intervention Using the Bern and Manchester Scores

The successful outcome of apical surgery is usually defined by absence of clinical signs and symptoms and resolution of previous periapical radiolucencies. However, little attention is given to soft tissue scarring. The present study evaluated the severity of gingival and mucosal scarring 1 year following apical surgery of 52 teeth. Clinical pictures taken at the 1-year examination were rated by three observers using specific scarring scores. The overall repeatability of the two scores was high (85.3%), whereas the overall reproducibility was relatively low (44.2%). None of the tested variables proved significant for influencing scar severity.

Bilateral necrotizing sialometaplasia of the hard palate in a patient with bulimia: a case report and review of the literature.

Necrotizing sialometaplasia (NS) is a rare and benign lesion that mostly affects the posterior hard palate. Its importance resides in its clinical and microscopic characteristics, which can closely mimic malignant neoplasias, in particular oral squamous cell carcinoma and mucoepidermoid carcinoma. Accurate histopathologic evaluation of an incisional biopsy is considered as the diagnostic gold standard. NS lesions heal spontaneously within weeks, and no further treatment is necessary. We report a case of a bilateral palatal NS in a 22-yearold woman with bulimia, where an incisional biopsy confirmed the clinical diagnosis. The different clinical stages of the lesions from onset to resolution and the possible etiologic factors are described in detail, as well as a discussion of the differential diagnoses of palatal ulcers. When taking a biopsy from suspicious oral lesions, care has to be taken that an appropriate tissue sample is harvested, and the histopathologic analysis is performed by an experienced pathologist to establish a correct diagnosis.