Vestibular bone thickness of the mandible in relation to the mandibular canal-a retrospective CBCT-based study.

BACKGROUND: The aim of this study was to assess vestibular bone thickness of the mandible in relation to the mandibular canal and position of the mental foramen in relation to the neighbouring teeth. Measurements were performed on radiographic cone-beam computed tomography (CBCT) images. METHODS: This retrospective study analysed 314 CBCTs, having been taken at the Clinic of Cranio-Maxillofacial and Oral Surgery, University of Zurich, Switzerland. RESULTS: CBCTs from 168 female and 146 male patients (median age 40.2 years) were analysed. Median bone thickness lateral to the nerve canal to the buccal mandibular cortical plate was ~ 4 mm immediately posterior to the mental foramen, increased to ≤ 6 mm over the next 30 mm, then decreased to ~ 3 mm at the level of the mandibular foramen. In two thirds of cases, both mental foramina were located near the second premolar (66.2% right, 67.7% left). Bone thickness and the position of the mental foramen showed marked intra- and interindividual variance. CONCLUSIONS: A preoperative CBCT is recommended for detailed planning of surgical interventions that may reach the mandibular canal (e.g. wisdom teeth removal, root resection, implant placement, bone block harvesting).

Radix occulta in antro.

Due to the anatomical proximity between the maxillary sinus and the teeth of the upper jaw, dislocation of tooth fragments or entire teeth into the sinus may occur during tooth extraction. Following the verification of such a foreign body within the sinus, its removal and the coverage of the oro-antral communication should be performed immediately for the prevention of possible sinus infection. In 2D-radiographic imaging, foreign bodies may not be located in the proper radiographic planes of an OPT or may be superimposed by other structures, complicating precise diagnosis. In such cases, 3D-imaging by CBCT is helpful. The present case report describes a female patient, being referred at our clinic for radiographic imaging and consecutive operative removal of a radix being dislocated into the right maxillary sinus. This radix relicta could be visualized by 3D-CBCT imaging. Consecutively, it was removed.

Preoperative 3D imaging in maxillary sinus: brief review of the literature and case report.

OBJECTIVE: The purpose of the present case report is to document the removal of a radix in antro without a hemorrhagic complication in presence of a posterior superior alveolar artery (PSAA) with a 2.8 mm diameter following a radiographic 3D planning by cone beam computed tomography (CBCT) scan. Furthermore, a brief literature overview on studies describing the existence and the variance of the PSAA is provided. METHOD AND MATERIALS: A foreign body removal in the right maxillary sinus was performed on a 33-year-old healthy man by using the lateral window osteotomy. The preoperative CBCT scan showed three arteries in the lateral maxillary sinus wall at a distance of 24.6 mm, 19.5 mm, and 13.5 mm to the alveolar crest. RESULTS: By removing a foreign body out of the maxillary sinus a vessel with a diameter of nearly 3 mm was exposed. Due to CBCT scan planning and the use of piezosurgery it was possible to avoid any damage to the vessel during the operation. The postoperative healing was uneventful and no complications occurred. CONCLUSION: Although laceration of vessels with a large diameter during lateral window osteotomy is not life-threatening it may compromise visualization and reduces the surgical outcome. Therefore, 3D imaging is recommended for the minimization of intra- and postoperative complications and for the localization of any foreign body in relation to other anatomical structures. This is of special interest in case of anatomical variances of blood vessels.

Evaluation of the maxillary sinus in panoramic radiography-a comparative study.

BACKGROUND: The aim of this study was to evaluate the validity and the inter- and intra-examiner reliability of panoramic-radiograph-driven findings of different maxillary sinus anatomic variations and pathologies, which had initially been prediagnosed by cone beam computed tomography (CBCT). METHODS: After pairs of two-dimensional (2D) panoramic and three-dimensional (3D) CBCT images of patients having received treatment at the outpatient department had been screened, the predefinition of 54 selected maxillary sinus conditions was initially performed on CBCT images by two blinded consultants individually using a questionnaire that defined ten different clinically relevant findings. Using the identic questionnaire, these consultants performed the evaluation of the panoramic radiographs at a later time point. The results were analyzed for inter-imaging differences in the evaluation of the maxillary sinus between 2D and 3D imaging methods. Additionally, two resident groups (first year and last year of training) performed two diagnostic runs of the panoramic radiographs and results were analyzed for inter- and intra-observer reliability. RESULTS: There is a moderate risk for false diagnosis of findings of the maxillary sinus if only panoramic radiography is used. Based on the ten predefined conditions, solely maxillary bone cysts penetrating into the sinus were frequently detected differently comparing 2D to 3D diagnostics. Additionally, on panoramic radiographs, the inter-observer comparison demonstrated that basal septa were significantly often rated differently and the intra-observer comparison showed a significant lack in reliability in detecting maxillary bone cysts penetrating into the sinus. CONCLUSIONS: Panoramic radiography provides the most information on the maxillary sinus, and it may be an adequate imaging method. However, particular findings of the maxillary sinus in panoramic imaging may be based on a rather examiner-dependent assessment. Therefore, a persistent and precise evaluation of specific conditions of the maxillary sinus may only be possible using CBCT because it provides additional information compared to panoramic radiography. This might be relevant for consecutive surgical procedures; consequently, we recommend CBCT if a precise preoperative evaluation is mandatory. However, higher radiation dose and costs of 3D imaging need to be considered.

[Risk assessment in patients undergoing osseous antiresorptive therapy in dentistry. An update]. / Risikobeurteilung von Patienten mit ossärer, antiresorptiver Therapie in der zahnärztlichen Praxis. Ein Update.

Antiresorptive therapy is prescribed in particular for the treatment of osteoporosis as well as for the treatment of tumor-induced hypercalcemia and metastatic bone disease. As a consequence, osteopathologies such as bisphosphonate-related osteonecrosis of the jaws (BRONJ) may occur. In 2008, our department reported on BRONJ in a paper that provided dental clinicians with information on diagnostics, therapy, and prevention (Dannemann et al., Schweizer Monatsschrift für Zahnmedizin, Vol. 118, 2/2008). During the last 8 years, new findings have emerged concerning potential etiologies, modes of therapy, and the use of additional antiresorptive therapies. For example, an important point for colleagues in dental practice is the now common intravenous administration of bisphosphonates in osteoporosis patients, which may lead to uncertainty when assessing risk in these patients. For this reason, this article provides an update of the above mentioned publication and gives dental clinicians an updated guideline concerning risk assessment in patients undergoing antiresorptive therapy. In this context, a risk assessment algorithm is presented. The pathogenesis, diagnosis, therapy, and prevention of BRONJ and oral implantation in patients receiving antiresorptive therapy are addressed with regard to the current literature. Finally, we present two example cases.

A case report of metastasis of malignant mesothelioma to the oral gingiva.

INTRODUCTION: Metastatic mesothelioma to the oral cavity arises from the pleura or peritoneum and distant hematogenous metastases are seen in more than half of cases but only a few cases are reported to the oral cavity. CASE: A 75 year old male suffering from metastatic mesothelioma presents an hyperplasia of the attached gingiva. Malignant mesothelioma is a rare tumour arising from pleura, pericardium or peritoneum. CONCLUSION: This article highlights the importance of biopsy and histopathological diagnosis of oral lesions especially in case of a malignant history.

Anatomy of impacted lower third molars evaluated by computerized tomography: is there an indication for 3-dimensional imaging?

OBJECTIVE: Surgical removal of impacted third molar is one of the most frequent procedures in oral surgery. Today 3-dimensional (3D) imaging is occasionally used. The aim of this study was to describe and estimate the frequencies of anatomic variations of lower third molars in patients with panoramic findings at high risk for inferior alveolar nerve (IAN) injury. STUDY DESIGN: The investigators designed and implemented a retrospective cases series study with a study population composed of patients presenting with an impacted lower third molar with projection of the tooth over the full width of the IAN in panoramic radiograph and, therefore, 3D imaging before a planned surgical removal. Spatial relationship to the IAN, type of angulation, root configuration and maturation were primary study variables. Descriptive statistics were computed for all variables. RESULTS: A total of 707 wisdom teeth in 472 patients (54% female, 46% male) were evaluated. A close relationship to the IAN was seen in 69.7%, and in 45.1% the diameter of the mandibular canal was reduced. In 52.8% the IAN was vestibular and in 37.3% lingual to the roots; there were 9.9% with an inter- or intraroot course. Most teeth had 1 or 2 roots (86.7%), but 13.3% had ≥3 roots. Mesial angulation was the main type (40.2%), followed by vertical (29%), horizontal (13.9%), distal (10.2%), and transverse (6.8%) positions. CONCLUSION: Based on the range of variations in the course of the nerve and the number of roots the authors recommend 3D imaging before surgical removal of a lower third molar that shows signs of a close relationship to the IAN.