Tuncer Özen

Measurements of mandibular canal region obtained by cone-beam computed tomography: a cadaveric study

OBJECTIVE The objective of this study was to assess the accuracy and reproducibility of cone-beam CT measurements of specific distances around the mandibular canal by comparing them to direct digital caliper measurements. METHODS Six formalin-fixed hemimandible specimens were examined using the ILUMA cone-beam CT system. Images were obtained at 120 kVp, 3.8 mA, and a voxel size of 0.2 mm, with an exposure time of 40 seconds. Specimens were cut into sections at 7 locations using a Lindemann burr, and a digital caliper was used to measure the following distances on both the anterior and posterior sides of each section: Mandibular Width (W); Mandibular Length (L); Upper Distance (UD); Lower Distance (LD); Buccal Distance (BD); and Lingual Distance (LID). The same distances were measured on the corresponding cross-sectional cone-beam CT images using the built-in measurement software. All caliper and cone-beam CT measurements were made by 2 independent trained observers and were repeated after an interval of 1 week. The Bland/Altman method was used to calculate intra- and inter-rater reliability. Intra-class correlation coefficients (ICCs) from 2-way random effects model were calculated. Agreements between cone-beam CT and direct digital caliper were calculated by ICC for 6 distances and 2 observers. RESULTS Intraobserver and interobserver measurements for all distances showed high agreement. ICCs for intraobserver agreement ranged from 0.86 to 0.97 for cone-beam CT measurements and from 0.98 to 0.99 for digital caliper measurements. ICCs between observers ranged from 0.84 to 0.97 for the cone-beam CT measurements and from 0.78 to 0.97 for the digital caliper measurements. ICCs for cone-beam CT and direct digital caliper ranged from 0.61 to 0.93 for the first observer and from 0.40 to 0.95 for the second observer. CONCLUSION Accuracy of cone-beam CT measurements of various distances surrounding the mandibular canal was comparable to that of digital caliper measurements.

Bone tissue responses to glass fiber‐reinforced composite implants – a histomorphometric study

OBJECTIVES The aims of this study were to evaluate bone-to-implant contact (BIC) and the osteoconductive capacity of bioactive fiber-reinforced composite implant (FRC) in vivo. MATERIAL AND METHODS Threaded sand-blasted FRC implants and threaded FRC implants with bioactive glass (BAG) were fabricated for the study. Titanium implants were used as a reference. Eighteen implants (diameter 4.1 mm, length 10 mm) were implanted in the tibia of six pigs using the press-fit technique. The animals were sacrificed after 4 and 12 weeks. Histomorphometric and scanning electron microscopic (SEM) analyses were performed to characterize BIC. RESULTS In general, the highest values of BIC were measured in FRC-BAG implants, followed by FRC and Ti implants. At 4 weeks, the BIC was 33% for threaded FRC-BAG, 27% for FRC and 19% for Ti. At 12 weeks, BIC was 47% for threaded FRC-BAG, 40% for FRC and 42% for Ti. Four weeks after implantation, all the implants appeared biologically fixed by a newly formed woven bone arranged in the thin bone trabeculae filling the gap between the implant and the bone of the recipient site. Twelve weeks after implantation, the thickness of the woven bone trabeculae had increased, especially around the FRC-BAG implants. CONCLUSION Our results suggest that the FRC implant is biocompatible in bone. The biological behavior of FRC was comparable to that of Ti after 4 and 12 weeks of implantation. Furthermore, the addition of BAG to the FRC implant increased peri-implant osteogenesis and bone maturation.

Interpretation of chemically created periapical lesions using 2 different dental cone-beam computerized tomography units, an intraoral digital sensor, and conventional film

OBJECTIVE To assess the diagnostic potential of 2 different cone-beam computerized tomography (CT) units and compare this with intraoral digital and conventional film in the detection of chemically created periapical lesions. STUDY DESIGN Periapical lesions were created chemically in 27 intact roots of 23 teeth (6 incisors, 4 canines, 6 premolars, and 7 molars). Cone-beam CT and digital and film images of the teeth were obtained before and after the lesions were created. Three observers separately used a 5-point scale to rate the images for the presence or absence of periapical pathology. Images were scored twice by each observer, with an interval of 4 weeks. Kappa values were calculated to assess intra- and interobserver agreement. Data were analyzed using repeated-measures analysis of variance for nested designs. R(2) values were used to assess the models for each observer for each method. Differences between observers and methods were tested for statistical significance with the paired t test. RESULTS Kappa coefficients for intraobserver agreement ranged from 0.196 to 0.542 for the 2-dimensional (2D) images and from 0.533 to 0.699 for the cone-beam CT images, whereas kappa coefficients for interobserver agreement ranged from 0.223 to 0.302 for the 2D images and from 0.417 to 0.461 for the cone-beam CT images. The R(2) values for each observer showed that cone-beam CT images were superior to 2D intraoral images. There was no difference between the 2 cone-beam CT units tested (P > .05), and no difference was found between the 2 intraoral radiographic techniques tested (P > .05). CONCLUSION The 2 cone-beam CT units tested performed similarly, and both performed better than intraoral digital and film radiography in detecting chemically created periapical lesions.

Efficacy of low level laser therapy on neurosensory recovery after injury to the inferior alveolar nerve

BackgroundThe most severe complication after the removal of mandibular third molars is injury to the inferior alveolar nerve or the lingual nerve. These complications are rather uncommon (0.4% to 8.4%) and most of them are transient. However, some of them persist for longer than 6 months, which can leave various degrees of long-term permanent disability. While several methods such as pharmacologic therapy, microneurosurgery, autogenous and alloplastic grafting can be used for the treatment of long-standing sensory aberrations in the inferior alveolar nerve, there are few reports regarding low level laser treatment. This paper reports the effects of low level laser therapy in 4 patients with longstanding sensory nerve impairment following mandibular third molar surgery.MethodsFour female patients had complaints of paresthesia and dysesthesia of the lip, chin and gingiva, and buccal regions. Each patient had undergone mandibular third molar surgery at least 1 year before. All patients were treated with low level laser therapy. Clinical neurosensory tests (the brush stroke directional discrimination test, 2-point discrimination test, and a subjective assessment of neurosensory function using a visual analog scale) were used before and after treatment, and the responses were plotted over time.ResultsWhen the neurosensory assessment scores after treatment with LLL therapy were compared with the baseline values prior to treatment, there was a significant acceleration in the time course, as well as in the magnitude, of neurosensory return. The VAS analysis revealed progressive improvement over time.ConclusionLow level laser therapy seemed to be conducive to the reduction of long-standing sensory nerve impairment following third molar surgery. Further studies are worthwhile regarding the clinical application of this treatment modality.

Diagnostic accuracy of different imaging modalities in detection of proximal caries

OBJECTIVE The purpose of this study was to assess the in vitro diagnostic ability of visual inspection, film, charge-coupled device (CCD) sensor, photostimulable phosphor (PSP) sensor and cone beam CT in the detection of proximal caries in posterior teeth compared with the histological gold standard. METHODS Visual inspection, film, CCD, PSP and cone beam CT images were used to detect proximal caries in the mesial and distal surfaces of 138 teeth (276 surfaces). Visual inspection and evaluation of all intraoral digital and conventional radiographs and cone beam CT images were performed twice by three oral radiologists. Weighted kappa coefficients were calculated to assess intra- and interobserver agreement for each image set, and scores were compared with the histological gold standard using receiver operating characteristic (ROC) analysis to evaluate diagnostic ability. RESULTS Intraobserver kappa coefficients calculated for each observer for each method of detecting caries ranged from 0.739 to 0.928. Strong interobserver agreement ranging from 0.631 to 0.811 was found for all detection methods. The highest Az values for all three observers were obtained with the cone beam CT images; however, differences between detection methods were not statistically significant (P > 0.05). CONCLUSION Visual inspection, film, CCD, PSP plates and cone beam CT performed similarly in the detection of proximal caries.

The position of the mandibular canal and histologic feature of the inferior alveolar nerve

The inferior alveolar nerve is the one of the large branches of the mandibular division of the trigeminal nerve. It is vulnerable during surgical procedures of the mandible. Despite its importance, no anatomical and histological examination has been conducted to provide a detailed cross‐sectional morphology of the mandibular canal according to dental status. Therefore, the present study aimed to identify the position of the mandibular canal through direct measurement and to determine the branches of the inferior alveolar nerve through histologic examination. The area between the anterior margin of the third molar and the anterior margin of the second premolar of dentulous, partially dentulous, and edentulous hemimandible specimens (n = 49) from 26 human cadavers was serially sectioned into seven segments, and specific distances were measured using digital calipers. Following this, 5‐μm cross‐sections were prepared along the mandibular canal and mental foramen, and examined by fluorescence microscopy. The mandibular canal was located at a mean distance of 10.52 mm above the inferior margin of the mandible. The mean maximum diameters of the mandibular canal, inferior alveolar nerve, inferior alveolar artery, and inferior alveolar vein were 2.52, 1.84, 0.42, and 0.58 mm, respectively. This study found that the inferior alveolar nerve often gives rise to several branches at each level (range 0–3). To minimize the risk of injury, knowledge of the small branches of the nerve and of the detailed findings regarding the position of the mandibular canal reported here should be considered when planning mandibular surgery, especially during implant placement. Clin. Anat. 23:34–42, 2010.

Is Endodontic Treatment Necessary During Coronectomy Procedure

PURPOSE Close proximity of the inferior alveolar nerve (IAN) to the third molar roots can result in nerve injuries during extraction of third molars. Consequently, it is necessary to determine the relationship of the nerve and roots to avoid damage to the IAN. Computed tomography scans are widely used to determine the correct relationship between the IAN and lower third molars. PATIENTS AND METHODS The study consisted of 10 patients with 16 lower third molars in close relationship with the IAN who were divided into a study group and a control group. The patients in the study group were treated via coronectomies performed with endodontic treatments. The patients in the control group underwent coronectomies without endodontic treatment. The patients were followed up for at least 1 year. RESULTS We had to extract 7 of the roots because of the infection in 8 patients belonging to the study group, which were treated endodontically. Moreover, there were 3 cases of IAN damage because of the extraction in the study group. However, in the control group, no infection was determined and IAN damage was absent. CONCLUSION Coronectomy appears to be a reliable technique to protect the IAN from damage. This procedure has a low incidence of complications. Endodontic treatment does not affect the success of this method according to our results.

Anatomic evaluation of maxillary sinus septa: surgery and radiology.

The anatomical structure of the maxillary sinus is fundamental to maxillofacial surgery. The presence of septa, located at the inner surface of the maxillary sinus, increases the risk of sinus membrane perforation during sinus elevation for dental implant surgery. The aim of this study was to evaluate the anatomy of maxillary sinus septa.Data in this study was obtained from a total of 205 cases. One hundred and seventy‐seven patients were partially edentulous (PE) whereas 28 patients had no teeth. Dental computerized tomography (dental CT) was used in the assessment of 410 sinus segments (205 left and 205 right segments). The prevalence of sinus segments with septa was found to be 145/410. Septa were detected in 91 of the 177 PE cases. There were a total of 26 septa in 18 of the 28 completely edentulous (CE) cases. A total of 165 septa were detected in these segments. The prevalence of septa was 46.4% (26/56) in the CE, and 39.2% (139/354) in the PE segments. Thirty septa were found in the anterior, 110 in the middle and 25 in the posterior region. All detected septa were located mediolateral direction. Their relative position: lateral, middle or medial were also noted. The height measurements of the septa varied amongst the different positions. In view of the fact that septa of various heights and courses can develop in all parts of the maxillary sinus, timely and adequate assessment of the inner aspect of the maxillary sinus is essential to avoid complications during sinus augmentation procedures. Clin. Anat. 22:563–570, 2009.

Accuracy of chemically created periapical lesion measurements using limited cone beam computed tomography

OBJECTIVES The aim was to assess the accuracy and reproducibility of measurements of chemically created periapical lesions using limited cone beam CT. METHODS Periapical lesions were chemically created in 18 mandibular cadaver teeth. Mandibles were dissected buccolingually using a bone-cutting burr. Diameters and depths were measured directly in the cross-sectional slices using a precision digital caliper. The cross-sectional slices were then embedded in wax, and cone beam CT images were acquired using a NewTom 3G Plus scanner with both 6 inch and 9 inch fields of view (FOVs). Two oral radiologists measured the diameter and depth of periapical lesions on the cross-sectional images using the built-in measurement tools. Measurements were repeated after a 1 week interval. Inter- and intraobserver agreement was calculated by ANOVA. Regression analysis was used to test the correlation between the cone beam CT and digital caliper measurements. RESULTS No significant differences were found in diameter or depth measurements between or within observers or between 6 inch and 9 inch FOV images. Regression analysis of diameter and depth measurements made by direct caliper versus 6 inch or 9 inch FOV images revealed a high regression coefficient (for diameter: 6 inch FOV, R(2) = 94.6%; 9 inch FOV, R(2) = 94.8%; P<0.001; for depth: 6 inch FOV, R(2) = 99.3%; 9 inch FOV, R(2) = 99.3%; P<0.001) showing a strong linear relationship. For the diameter, the mean deviation from direct caliper measurements was 0.0625 mm and 0.08958 mm, respectively; for the 6 inch FOV and 9 inch FOV images, and for depth, the mean deviation was, respectively, -0.1001 mm and 0.09875 mm. CONCLUSIONS Cone beam CT yielded highly accurate and reproducible results in the quantitative assessment of periapical lesions.

Proximal caries detection accuracy using intraoral bitewing radiography, extraoral bitewing radiography and panoramic radiography

OBJECTIVE To compare proximal caries detection using intraoral bitewing, extraoral bitewing and panoramic radiography. METHODS 80 extracted human premolar and molar teeth with and without proximal caries were used. Intraoral radiographs were taken with Kodak Insight film (Eastman Kodak Co., Rochester, NY) using the bitewing technique. Extraoral bitewing and panoramic images were obtained using a Planmeca Promax Digital Panoramic X-ray unit (Planmeca Inc., Helsinki, Finland). Images were evaluated by three observers twice. In total, 160 proximal surfaces were assessed. Intra- and interobserver kappa coefficients were calculated. Scores obtained from the three techniques were compared with the histological gold standard using receiver operating characteristic analysis. Az values for each image type, observer and reading were compared using z-tests, with a significance level of α = 0.05. RESULTS Kappa coefficients ranged from 0.883 to 0.963 for the intraoral bitewing, from 0.715 to 0.893 for the extraoral bitewing, and from 0.659 to 0.884 for the panoramic radiography. Interobserver agreements for the first and second readings for the intraoral bitewing images were between 0.717 and 0.780, the extraoral bitewing readings were between 0.569 and 0.707, and the panoramic images were between 0.477 and 0.740. The Az values for both readings of all three observers were highest for the intraoral bitewing. Az values for the extraoral bitewing images were higher than those of the panoramic images without statistical significance (p > 0.05). CONCLUSION Intraoral bitewing radiography was superior to extraoral bitewing and panoramic radiography in diagnosing proximal caries of premolar and molar teeth ex vivo. Similar intra- and interobserver coefficients were calculated for extraoral bitewing and panoramic radiography.