Musa Can Ucan

Mandibular fractures: a comparative analysis between young and adult patients in the southeast region of Turkey

Objective The purpose of this study was to review and compare the differences between mandibular fractures in young and adult patients. Material and Methods Patients treated at the Oral and Maxillofacial Department of Dicle University during a five-year period between 2000 and 2005 were retrospectively evaluated with respect to age groups, gender, etiology, localization and type of fractures, treatment methods and complications. Result 532 patients were included in the study, 370 (70%) males and 162 (30%) females, with a total of 744 mandibular fractures. The mean age of young patients was 10, with a male-female ratio of 2:1. The mean age of adult patients was 28, with a male-female ratio of 3:1. The most common causes of injury were falls (65%) in young patients and traffic accidents (38%) in adults. The most common fracture sites were the symphysis (35%) and condyle (36%) in young patients, and the symphysis in adults (36%). Mandibular fractures were generally treated by arch bar and maxillomandibular fixation in both young (67%) and adult (39%) patients, and 43% of the adult patients were treated by open reduction and internal fixation. Conclusion There was a similar gender, monthly and type of treatment distribution in both young and adult patients in the southeast region of Turkey. However, there were differences regarding age, etiology and fracture site. These findings between young and adult patients are broadly similar to those from other studies. Analysis of small differences may be an important factor in assessing educational and socioeconomic environments.

Influence of caffeic acid phenethyl ester on bone healing in a rat model

Objective To examine the effects of caffeic acid phenethyl ester (CAPE; a component of honey bee-hive propolis with antioxidant, anti-inflammatory, antiviral and anticancer properties) on bone regeneration and fibrotic healing in a rat model. Methods Male Sprague–Dawley rats (n = 63; mean age 7 weeks; weight 280–490 g) were randomly divided into three groups: A, cranial defect with no bone healing treatment (n = 21); B, cranial defect treated with CAPE (n = 21); C, cranial defect treated with CAPE and β-tricalcium phosphate/hydroxyl apatite (n = 21). Rats were anaesthetized with ketamine (8 mg/100 g) by intraperitoneal injection and a cranial critical size bone defect was created. Following surgery, CAPE (10 µmol/kg) was administered by daily intraperitoneal injection. Seven rats in each group were killed at days 7, 15 and 30 following surgery. Bone regeneration, fibrotic healing and osteoblast activity were evaluated by histopathology. Results Statistically significant differences in healing were found between all groups. There were no statistically significant within-group differences between day 7 and 15. At day 30, bone healing scores were significantly higher in groups B and C compared with group A. Conclusion CAPE significantly improved bone-defect healing in a rat model, suggesting that CAPE has beneficial effects on bone healing.

A Three Dimensional Analysis of Reconstruction Plates used in Different Mandibular Defects

ABSTRACT In this study, the reasons of breaking of the reconstruction plates used in mandibular continuity or mandibular defects were investigated. The study was conducted on 3 cases in which reconstruction plates were used for tumor resection or invasive wound. The objective was to evaluate the mechanical stress in reconstruction plates by means of the finite element method. Three dimensional model of reconstruction plate was exposed to chewing force. A commercial finite element solver (ANSYS) was then applied to this plate to compute the stresses generated in chewing situation. Stress analyses have been carried out by applying Von Mises Yielding Criteria. In the standard reconstruction plate, the results of the finite element analysis revealed that stress resulting from the simulated functional loadings which far exceeded the strengths of the components. The main application of this study was the prediction of fractures as a consequence of known forces. If it was assumed that the patient executes several thousand masticatory movements within a week, a dynamic strain would be present due to the large number of changes in loading, so that there was a danger of a fatigue fracture at the point of the stress concentration (as seen in the analysis), as is also confirmed by clinical practice.

Comparison of the effects of different loading locations on stresses transferred to straight and angled implant-supported zirconia frameworks: a finite element method study

The paper presents three-dimensional (3D) finite element models of straight and angled implants and their zirconium-based superstructures. The key objective was to compare the influence of different loading conditions on the stress distribution of straight and angled implants and the zirconia frameworks. 3D finite element straight- and angled-implant models of a mandibular section of bone with missing second molars and their zirconium-based superstructures were used. The straight and angled implants were 4.7 × 13-mm screw-type dental implant systems. Total loads of 300 N were applied in a vertical direction and in an oblique (30° to the vertical) direction buccolingually. Maximum and minimum von Mises stress values of the titanium structures (abutment and implant body) and zirconia frameworks were calculated. When the two groups were examined, the highest stress value was in the zirconia framework of the angled implant-supported model with an oblique loading force (731.46 MPa). The lowest stress values were concentrated in the straight implant-supported model. Thus, the stress values in the angled implant-supported crown were higher than those in the straight implant-supported model. Stress values with oblique loading forces were higher than the values with vertical loading forces. The highest stress value in the zirconia framework was similar to the ultimate strength of the zirconia.

Three-dimensional finite-element analysis of a single implant-supported zirconia framework and its effect on stress distribution in D4 (maxilla) and D2 (mandible) bone quality

The aim of this in-silico study was to compare stress distributions in implants and zirconia frameworks of mandibular and maxillary implant-supported crowns. For comparison, vertical and oblique loading forces were used. Three-dimensional finite-element implant models of a mandibular section of bone (D2) and a maxillary section of bone (D4) with missing second molars and their zirconium-based superstructures were used. Zimmer dental implants of 13 mm in length and 4.7 mm in diameter were modelled. A load of 200 N was applied toward vertical and oblique (30° to the vertical) directions. Maximum and minimum von Mises stress values of the implants and the zirconia framework were calculated. The highest stress value was concentrated in the zirconia framework of the maxillary implant-supported model with the oblique loading force (301.17 MPa). The lowest stress value was concentrated in the mandibular implant-supported model. And the stress values in the maxilla were higher than in the mandible. The maxilla (D4) showed higher stress values than in the mandible (D2), because the trabecular bone is weaker and less resistant to deformation than the cortical bone. Stress values with oblique loading forces were higher than with vertical loading forces. Because of the high Youngs modulus of zirconia (low elastic properties), zirconia frameworks showed higher stress values than the implants.

Examination of stress distribution and fracture resistance in five-unit tooth- and implant-supported partial fixed zirconia prosthesis

In this study, stress distribution and fracture strength values of zirconia frameworks were compared in five-unit tooth- and implant-supported fixed zirconia prosthesis. Three-dimensional finite element stress analysis and static non-linear analysis were used. Because of the boundary conditions determined for these methods, the tooth- and implant-supported models only included the regions of tooth numbers 43–47. The highest stress value (901.845 MPa) was measured in Model 1 (five-unit tooth-supported fixed zirconia bridge) at the mesial gingival neck area of restoration number 45. This stress value was within the ultimate strength of zirconia (900–1200 MPa). Stress values for connector regions were not in the ultimate strength value of zirconia. Stress values in the tooth-supported fixed zirconia bridge were more than the values in the implant-supported fixed zirconia bridge. The highest stresses in Model 2 (five-unit implant-supported fixed zirconia bridge) occurred in the restoration that the model was installed on. The obtained results showed that five-unit tooth-supported posterior zirconia fixed bridge prostheses are not recommended and that the second premolar region is most seriously affected in terms of stress.

Evaluation of retrograde intubation in patients with limited mouth opening

To the Editor: Tracheal intubation may be difficult due to limited mouth opening or other anatomical abnormalities. Fiberoptic-assisted nasotracheal intubation is the technique of choice in such cases, but a fiberoptic bronchoscope is not always available, especially in hospitals situated in rural areas. We retrospectively investigated the advantages/disadvantages of retrograde intubation in patients with limited mouth opening by evaluating the hospital records of 28 consecutive patients who had undergone retrograde intubation. The success rate, procedure time, number of attempts, and frequency of complications were recorded. A signed consent form was obtained from each patient for all surgical and anesthesia applications. The institutional ethics committee approved the study. In our study, retrograde intubation was performed as described previously [1] in 28 patients (17 male and 11 female, mean age 27 ± 5 years). The mean body mass index was 24 ± 4. Twenty-one patients had temporomandibular joint ankylosis, and seven patients had maxillamandibular fracture. Mean time for retrograde intubation was 3.9 min. Overall success rate was 100 % and success rate of the first attempt was 67.9 %. In three patients, we performed tracheal puncture with a needle on the second attempt. If the guidewire was placed intraorally, it was withdrawn to the oropharanx position and then repositioned to the nasopharanx. In 11 (39.3 %) and 12 (42.9 %) patients, the guidewire was grasped successfully on the first and second attempt, respectively. An endotracheal tube was placed into the trachea on the first attempt in 19 (67.9 %) patients; a second attempt was performed in seven patients. The total procedure time was\5 min in 25 (82.1 %) patients. There was no episode of hypoxemia (pulse oxygen saturation \93 %) during intubation. We found no other evidence of esophagus or airway trauma, nor of serious epistaxis. Minimal bleeding into the trachea was observed in three patients. Additionally, sore throat was present in seven patients on the second-day control after the operation. No other complications were observed during and after the procedures. Retrograde tracheal intubation is a simple and quick procedure when performed by experienced practitioners and may be reliably used in patients with limited mouth opening, including facial trauma and temporomandibular joint ankylosis. Compared to fiberoptic bronchoscope-guided intubation, retrograde tracheal intubation has its advantages and disadvantages. It is a slightly invasive procedure with a number of potential complications, such as tracheoesophageal fistula, vocal cord damage, and bleeding [2]. The advantages of retrograde intubation over fiberoptic bronchoscope-guided intubation include its possible applicability when blood or secretions are present in the upper airway and in patients with an immobilized neck, shorter procedural duration, and a lower risk of subglottic edema and stenosis [3]. In the absence of fiberoptic bronchoscope, blind nasal intubation is another method for endotracheal intubation, but in patients with severe flexion A. Tufek (&) O. Tokgoz F. Celik Department of Anesthesiology, Faculty of Medicine, Dicle University, 21280 Diyarbakir, Turkey e-mail: adnantufek@hotmail.com