Local Application of BMP-2 Specific Plasmids in Fibrin Glue does not Promote Implant Fixation

<p>Abstract</p> <p>Background</p> <p>BMP-2 is known to accelerate fracture healing and might also enhance osseointegration and implant fixation. Application of recombinant BMP-2 has a time-limited effect. Therefore, a gene transfer approach with a steady production of BMP-2 appears to be attractive. The aim of this study was to examine the effect of locally applied BMP-2 plasmids on the bone-implant integration in a non-weight bearing rabbit tibia model using a comparatively new non-viral copolymer-protected gene vector (COPROG).</p> <p>Methods</p> <p>Sixty rabbits were divided into 4 groups. All of them received nailing of both tibiae. The verum group had the nails inserted with the COPROG vector and BMP-2 plasmids using fibrin glue as a carrier. Controls were a group with fibrin glue only and a blank group. After 28 and 56 days, these three groups were sacrificed and one tibia was randomly chosen for biomechanical testing, while the other tibia underwent histomorphometrical examination. In a fourth group, a reporter-gene was incorporated in the fibrin glue instead of the BMP-2 formula to prove that transfection was successful.</p> <p>Results</p> <p>Implant fixation strength was significantly lower after 28 and 56 days in the verum group. Histomorphometry supported the findings after 28 days, showing less bone-implant contact.</p> <p>In the fourth group, successful transfection could be confirmed by detection of the reporter-gene in 20 of 22 tibiae. But, also systemic reporter-gene expression was found in heterotopic locations, showing an undesired spreading of the locally applied gene formula.</p> <p>Conclusion</p> <p>Our results underline the transfecting capability of this vector and support the idea that BMP-2 might diminish osseointegration. Further studies are necessary to specify the exact mechanisms and the systemic effects.</p

Detectability of Osseous Lesions with a Pre-Programmed Low-Dose Protocol for Cone-Beam Computed Tomography

The present study aimed to compare the diagnostic reliability of a pre-set, manufacturer-specific, low-dose mode against a standard-dose mode in the detection of four different osseous lesions in the mandible with cone-beam computed tomography (CBCT). Four types of lesions (periapical lesion, extended periodontal gap, recession of the buccal lamella, sequestrum/fracture) were prepared on 40 pig mandibles. CBCT images were obtained from each mandible, with both the low-dose and standard-dose modes using the Orthophos SL CBCT device (Dentsply-Sirona, Bensheim, Germany). Twelve assessors quantitatively (detection of lesions) and qualitatively (assessment of detectability) evaluated the CBCT images in SIDEXIS 4 (Dentsply-Sirona) using a study-specific digital examination tool. A correct diagnosis was achieved in almost 71% (LD: 70.8%; SD: 70.9%) of 1920 lesions, without a statistically significant difference between the low-dose and standard-dose mode. This finding was consistent across all four lesion types. In conclusion, while low-dose mode and standard-dose mode CBCT scans performed similarly in the detection of four prepared lesions of the mandible, the former may be a promising, user-friendly alternative method of obtaining radiation-optimized, three-dimensional images in accordance with the As Low As Diagnostically Acceptable (ALADA) principle

Oral lichen planus (OLP), oral lichenoid lesions (OLL), oral dysplasia, and oral cancer: Retrospective analysis of clinicopathological data from 2002-2011

INTRODUCTION: This 10-year retrospective study analyzed the incidence of malignant transformation of oral lichen planus (OLP). The study also included dysplasia and oral lichenoid lesion (OLL) in the initial biopsy as a potential differential diagnosis. MATERIAL AND METHODS: A total of 692 scalpel biopsies were taken from 542 patients (207 [38.2 %] men and 335 [61.8 %] women). Clinical and histopathological parameters were analyzed. RESULTS: The parameters gender (p = 0.022) and smoking behavior (p < 0.001) were significantly associated with the severity of diagnosis. Mucosal lesions with an ulcerative appearance (p = 0.006) and those located on the floor of the mouth (p < 0.001) showed significantly higher degrees of dysplasia or were diagnosed as oral squamous cell carcinoma (OSCC). Smoking and joint disease appeared to be significant risk factors. Treatment with tretinoin in different concentrations (0.005-0.02 %) significantly improved diagnosis. Twelve patients (8 female, 4 male) showed malignant transformation to OSCC within an average period of 1.58 years. The malignant transformation rate (MTR) was higher for OLL (4.4 %) than OLP (1.2 %). If the first biopsy showed intraepithelial neoplasia, the risk of developing OSCC increased (by 3.5 % for squamous intraepithelial neoplasia (SIN) II and by 6.7 % for SIN III). CONCLUSION: Although we cannot rule out that OLP is a premalignant oral condition, we can confirm that OLP had the lowest MTR of all diagnoses

Anatomical characteristics of maxillary sinus septa visualized by cone beam computed tomography

Proper implant positioning in the posterior region of the edentulous maxilla commonly requires sinus floor elevation. Maxillary sinus septa increase the risk of membrane perforation during sinus floor elevation. The purpose of this retrospective, cone beam computed tomography (CBCT)-based study was to examine the frequency, number, location, and orientation of antral septa in the maxillary sinus. Further, possible associated factors were assessed. Measurements were performed on CBCT scans of 301 patients (602 sinuses). The data were analysed statistically with respect to patient age, sex, and dentition type. One or more septa were detected in 117 patients (38.9%). A total of 188 septa were found in the 602 sinuses (31.2%). Septa were most often coronally oriented (53.2%), followed by sagittal (24.5%) and transverse (22.3%) orientations. Septa were most often found in the region of the first and second molar (37.2%), followed by the posterior region of the third molar (33.0%) and the anterior region of the premolars and canines (29.8%). A significant association was found between edentulism and the presence of septa. For edentulous patients, the septa were most often transversally oriented. Maxillary sinus septa are encountered in every third patient. This may have an influence on the performance of sinus floor elevation

Evaluation of oral prophylaxis during and after intensity-modulated radiotherapy due to head and neck cancer-a retrospective study

OBJECTIVES The aim of this study was to retrospectively analyze the influence of a prophylaxis protocol of head and neck tumor (HNT) patients during and after intensity-modulated radiotherapy (IMRT). MATERIAL AND METHOD In this 5-year retrospective study (2009-2013), 70 (m 55, f 15; age range 28-8 years; median 58.7 years) out of 248 HNT patients of the Clinic of Cranio-Maxillofacial and Oral Surgery at the University of Zurich, Switzerland, fulfilled the inclusion criteria. Parameters of investigation were the salivary flow rates, possible dental foci and the dental status, oral side effects of radiotherapy, the prophylaxis protocol, and patient's compliance to this protocol. The following time points before during and after IMRT (6 weeks) were analyzed: prior to IMRT, 2-4 weeks, 6 weeks and 3, 6, and 12 months after the onset of radiotherapy. RESULT Unstimulated salivary flow rate, pH value of unstimulated salivary, and stimulated salivary flow rate showed a significant reduction over time (p < 0.001). One year after IMRT, both unstimulated and stimulated salivary flow showed a statistically significant lower salivary flow. The number of caries-affected sites per patient was significantly higher for patients with low compliance to the prophylaxis protocol (mean: low compliance 1.36, high compliance 0.26). Almost 75 % of the evaluated patients suffered immediate gustatory change, and 47.1 % showed signs of radiostomatitis through IMRT. CONCLUSIONS High compliance to the prophylaxis protocol during and after radiotherapy is a key factor for the reduction of radiation side effects on dental hard tissue. CLINICAL RELEVANCE High compliance to a monitored prophylaxis program is crucial for patients after head and neck surgery

Osseointegration of biochemically modified implants in an osteoporosis rodent model

The present study examined the impact of implant surface modifications on osseointegration in an osteoporotic rodent model. Sandblasted, acid-etched titanium implants were either used directly (control) or were further modified by surface conditioning with NaOH or by coating with one of the following active agents: collagen/chondroitin sulphate, simvastatin, or zoledronic acid. Control and modified implants were inserted into the proximal tibia of aged ovariectomised (OVX) osteoporotic rats (n = 32/group). In addition, aged oestrogen competent animals received either control or NaOH conditioned implants. Animals were sacrificed 2 and 4 weeks post-implantation. The excised tibiae were utilised for biomechanical and morphometric readouts (n = 8/group/readout). Biomechanical testing revealed at both time points dramatically reduced osseointegration in the tibia of oestrogen deprived osteoporotic animals compared to intact controls irrespective of NaOH exposure. Consistently, histomorphometric and microCT analyses demonstrated diminished bone-implant contact (BIC), peri-implant bone area (BA), bone volume/tissue volume (BV/TV) and bone-mineral density (BMD) in OVX animals. Surface coating with collagen/chondroitin sulphate had no detectable impact on osseointegration. Interestingly, statin coating resulted in a transient increase in BIC 2 weeks post-implantation; which, however, did not correspond to improvement of biomechanical readouts. Local exposure to zoledronic acid increased BIC, BA, BV/TV and BMD at 4 weeks. Yet this translated only into a non-significant improvement of biomechanical properties. In conclusion, this study presents a rodent model mimicking severely osteoporotic bone. Contrary to the other bioactive agents, locally released zoledronic acid had a positive impact on osseointegration albeit to a lesser extent than reported in less challenging models

Detectability of Osseous Lesions with a Pre-Programmed Low-Dose Protocol for Cone-Beam Computed Tomography

The present study aimed to compare the diagnostic reliability of a pre-set, manufacturer-specific, low-dose mode against a standard-dose mode in the detection of four different osseous lesions in the mandible with cone-beam computed tomography (CBCT). Four types of lesions (periapical lesion, extended periodontal gap, recession of the buccal lamella, sequestrum/fracture) were prepared on 40 pig mandibles. CBCT images were obtained from each mandible, with both the low-dose and standard-dose modes using the Orthophos SL CBCT device (Dentsply-Sirona, Bensheim, Germany). Twelve assessors quantitatively (detection of lesions) and qualitatively (assessment of detectability) evaluated the CBCT images in SIDEXIS 4 (Dentsply-Sirona) using a study-specific digital examination tool. A correct diagnosis was achieved in almost 71% (LD: 70.8%; SD: 70.9%) of 1920 lesions, without a statistically significant difference between the low-dose and standard-dose mode. This finding was consistent across all four lesion types. In conclusion, while low-dose mode and standard-dose mode CBCT scans performed similarly in the detection of four prepared lesions of the mandible, the former may be a promising, user-friendly alternative method of obtaining radiation-optimized, three-dimensional images in accordance with the As Low As Diagnostically Acceptable (ALADA) principle

Diagnostic Accuracy of Cystic Lesions Using a Pre-Programmed Low-Dose and Standard-Dose Dental Cone-Beam Computed Tomography Protocol: An Ex Vivo Comparison Study

Background: This study aimed to analyze the diagnostic reliability of radiographic assessment of cystic lesions using a pre-set, manufacturer-specific, low-dose mode compared to a standard-dose dental cone-beam computed tomography (CBCT) imaging protocol. Methods: Forty pig mandible models were prepared with cystic lesions and underwent both CBCT protocols on an Orthophos SL Unit (Dentsply-Sirona, Bensheim, Germany). Qualitative and quantitative analysis of CBCT data was performed by twelve investigators independently in SIDEXIS 4 (Dentsply-Sirona) using a trial-specific digital examination software tool. Thereby, the effect of the two dose types on overall detectability rate, the visibility on a scale of 1 (very low) to 10 (very high) and the difference between measured radiographic and actual lesion size was assessed. Results: Low-dose CBCT imaging showed no significant differences considering detectability (78.8% vs. 81.6%) and visibility (9.16 vs. 9.19) of cystic lesions compared to the standard protocol. Both imaging protocols performed very similarly in lesion size assessment, with an apparent underestimation of the actual size. Conclusion: Low-dose protocols providing confidential diagnostic evaluation with an improved benefit–risk ratio according to the ALADA principle could become a promising alternative as a primary diagnostic tool as well as for radiological follow-up in the treatment of cystic lesions

Oral lichen planus (OLP), oral lichenoid lesions (OLL), oral dysplasia, and oral cancer: retrospective analysis of clinicopathological data from 2002-2011

Introduction: This 10-year retrospective study analyzed the incidence of malignant transformation of oral lichen planus (OLP). The study also included dysplasia and oral lichenoid lesion (OLL) in the initial biopsy as a potential differential diagnosis. Material and methods: A total of 692 scalpel biopsies were taken from 542 patients (207 [38.2%] men and 335 [61.8%] women). Clinical and histopathological parameters were analyzed. Results: The parameters gender (p = 0.022) and smoking behavior (p < 0.001) were significantly associated with the severity of diagnosis. Mucosal lesions with an ulcerative appearance (p = 0.006) and those located on the floor of the mouth (p < 0.001) showed significantly higher degrees of dysplasia or were diagnosed as oral squamous cell carcinoma (OSCC). Smoking and joint disease appeared to be significant risk factors. Treatment with tretinoin in different concentrations (0.005-0.02%) significantly improved diagnosis. Twelve patients (8 female, 4 male) showed malignant transformation to OSCC within an average period of 1.58years. The malignant transformation rate (MTR) was higher for OLL (4.4%) than OLP (1.2%). If the first biopsy showed intraepithelial neoplasia, the risk of developing OSCC increased (by 3.5% for squamous intraepithelial neoplasia (SIN) II and by 6.7% for SIN III). Conclusion: Although we cannot rule out that OLP is a premalignant oral condition, we can confirm that OLP had the lowest MTR of all diagnoses