The potential of nano graphene oxide and chlorhexidine composite membranes for use as a surface layer in functionally graded membranes for periodontal lesions.

Membranes have been used for treating periodontal defects and play a crucial role in guided bone regeneration applications. Nano graphene oxide have been exploited in tissue engineering due to its biomechanical properties. Its composite formulations with hydroxyapatite and chitosan with controlled degradation could aid in becoming part of a surface layer in a functionally graded membrane. The aim of the study was to synthesize chitosan and composite formulations of nano graphene oxide, hydroxyapatite and chlorhexidine digluconate using solvent casting technique and to characterize the physiochemical, mechanical, water vapor transmission rate (barrier), degradation and antimicrobial potential of the membranes. Altogether four different membranes were prepared (CH, CCG, 3511 and 3322). Results revealed the chemical interactions of hydroxyapatite, chitosan and nanographene oxide due to inter and intra molecular hydrogen bonding. The tensile strength of 3322 (33.72 ± 6.3 MPa) and 3511 (32.06 ± 5.4 MPa) was higher than CH (27.46 ± 9.6 MPa). CCG showed the lowest water vapor transmission rate (0.23 ± 0.01 g/h.m2) but the highest weight loss at day 14 (76.6 %). 3511 showed a higher drug release after 72 h (55.6 %) Significant biofilm growth inhibition was observed for all membranes. 3511 showed complete inhibition against A. actinomycetemcomitans. Detailed characterization of the synthesized membranes revealed that 3511 composite membrane proved to be a promising candidate for use as a surface layer of membranes for guided bone regeneration of periodontal lesions.

Bone regeneration using composite non-demineralized xenogenic dentin with beta-tricalcium phosphate in experimental alveolar cleft repair in a rabbit model.

BACKGROUND: Alveolar cleft repair is performed via bone grafting procedure to restore the dental arch continuity. A suitable bone substitute materials should possess osteoinductive and osteoconductive properties, to promote new bone formation, along with a slowly resorbable scaffold that is subsequently replaced with functionally viable bone. Calcium phosphate biomaterials have long proved their efficacy as bone replacement materials. Dentin in several forms has also demonstrated its possibility to be used as bone graft replacement material in several studies. The purpose of this study was to evaluate bone regeneration pattern and quantify bone formation after grafting pre-established experimental alveolar clefts defects model in rabbits using composite xenogenic dentin and ß-TCP in comparison to ß-TCP alone. METHODS: Unilateral alveolar cleft defects were created in 16 New Zealand rabbits according to previously described methodology. Alveolar clefts were allowed 8 weeks healing period. 8 defects were filled with ß-TCP, whereas 8 defects filled with composite xenogenic dentin with ß-TCP. Bone regeneration of the healed defects was compared at the 8 weeks after intervention. Quantification of bone formation was analyzed using micro-computed tomography (µCT) and histomorphometric analysis. RESULTS: µCT and histomorphometric analysis revealed that defects filled with composite dentin/ß-TCP showed statistically higher bone volume fraction, bone mineral density and percentage residual graft volume when compared to ß-TCP alone. An improved surgical handling of the composite dentin/ß-TCP graft was also noted. CONCLUSIONS: Composite xenogenic dentin/ß-TCP putty expresses enhanced bone regeneration compared to ß-TCP alone in the reconstruction of rabbit alveolar clefts defects.

Demineralized Xenogenic Dentin and Autogenous Bone as Onlay Grafts to Rabbit Tibia.

PURPOSE: The present study was undertaken to evaluate the healing pattern of xenogenic demineralized dentin onlay grafts in comparison with autogenous bone grafts to the rabbit tibia. MATERIAL AND METHODS: Eight 6-month-old New Zealand male rabbits were used in the experiments. Standardized sized dentin blocks from human premolars and similar autogenous bone blocks harvested from tibia were grafted as onlay blocks on each tibia (n = 8 × 2). All animals were killed after a healing period of 12 weeks. RESULTS: Healing was uneventful for all animals. In general, both the dentin and bone block grafts were fused to the bone, resorbed, and replaced by bone and connective tissue to a varying degree. Both types of grafts were still present after 12 weeks, on an average to approximately one third of the original sizes. Resorption cavities could be seen in the dentin with bone formation. Zones of osseous replacement resorption of the dentin could be noted. In both graft types, higher rate of bone formation was seen at the interface between graft and recipient site. CONCLUSION: Demineralized xenogenic dentin onlay grafts showed similar resorption characteristics as autogenous bone onlay grafts, being resorbed in a similar rate during 12 weeks. New bone formation occurred mainly in terms of replacement resorption in the interface between dentin/bone graft and native bone.

Host tissue reactions of non-demineralized autogenic and xenogenic dentin blocks implanted in a non-osteogenic environment. An experimental study in rabbits.

Dentoalveolar ankylosis with osseous replacement is often seen after replantation of avulsed teeth, and this process may be used for preservation of alveolar crests after trauma. Its exact mechanisms with regard to osteoinductive properties are not yet fully understood and need to be systematically investigated. Dentin can possibly act as a slow-releasing carrier of bone morphogenic proteins (BMP), and this property of dentin has been proposed to be used as an alternative or supplement to bone grafting in the maxillofacial region. We aimed to initially asses host tissue reactions to dentin by implanting dentin blocks of autogenic and xenogenic human origin in rabbit connective tissue of the abdominal wall and femoral muscle. Animals were sacrificed after a period of 3 months, and histological processing, sectioning and examinations were carried out. Bone formation, cell counts and thickness of capsule surrounding the grafts were evaluated. Only minor signs of heterotopic bone formation were seen. There were no significant differences between autografts and xenografts or grafts implanted in connective tissue or muscle with regards to tissue reactions except for a significant difference (P = 0.018) in findings of more local inflammatory cells in relation to grafts placed in connective tissue in the autograft group. We conclude that during the time frame of this study, non-demineralized dentin, whether autogenous or xenogenic did not have the potential to induce bone formation when implanted in non-osteogenic areas such as the abdominal wall and abdominal muscle of rabbits.

Growth Suppression of Oral Squamous Cell Carcinoma Cells by Lactobacillus Acidophilus.

OBJECTIVES: Oral squamous cell carcinoma (OSCC) is a highly aggressive form of oral cancer. Probiotic lactobacilli have demonstrated anticancer effects, whilst their interaction with Streptococcus mutans in this context remains unexplored. The objective of this study was to investigate the antiproliferative effect of Lactobacillus acidophilus on OSCC and to understand the effect of S mutans on OSCCs and whether it affects the antiproliferative potential of L acidophilus when co-exposed to OSCC. METHODS: The human head and neck squamous cell carcinoma cells of the oral cavity (HNO97 cell line) were exposed to cultures of L acidophilus and S mutans separately and in combination. Further, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to assess the viability of HNO97 cells. Bacterial adhesion to HNO97 cells was examined by confocal microscopy and apoptosis by Nexin staining. To understand the underlying mechanism of apoptosis, expression of the tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) gene and protein were determined by real-time polymerase chain reaction and quantitative enzyme-linked immunosorbent assay, respectively. RESULTS: A significant decrease (53%-56%) in the viability of HNO97 cells on exposure to L acidophilus, S mutans, and the 2 species together demonstrated the antiproliferative activity of L acidophilus and S mutans. Both bacteria showed adhesion to HNO97 cells. The expression of the TRAIL gene increased 5-fold in HNO97 cells on treatment with L acidophilus and S mutans, which further increased to ∼17-fold with both species present. Expression levels of the TRAIL protein were significantly (P < .05) increased in bacteria-treated cell lysates. Further, bacteria-treated HNO97 cells exhibited lower live and intact cell percentages with higher proportions of cells in early and late apoptotic stages. CONCLUSIONS: L acidophilus exhibits the antiproliferative activity against OSCC cells possibly partially via a TRAIL-induced mechanism of apoptosis, which is not affected by the presence of S mutans. These findings may encourage further investigation into the possible therapeutic application of probiotic L acidophilus in OSCC.

Adhesion of Candida albicans on PTFE membranes used in guided bone regeneration.

OBJECTIVES: Guided bone regeneration (GBR) is a core procedure used to regenerate bone defects. The aim of the study was to investigate the adherence of Candida albicans on six commercially available polytetrafluoroethylene (PTFE) membranes used in GBR procedures and the subsequent clinical consequences. MATERIALS AND METHODS: Six commercially available PTFE membranes were tested. Two of the membranes had a textured surface and the other four a plane, nontextured one. C. albicans (ATCC 24433) was cultured for 24 h, and its cell surface hydrophobicity was assessed using a modified method. C. albicans adhesion to membrane discs was studied by scanning electron microscopy (SEM) and real-time polymerase chain reaction (PCR). RESULTS: C. albicans was found to be hydrophobic (77.25%). SEM analysis showed that C. albicans adherence to all membranes examined was characterized by patchy, scattered, and small clustered patterns except for one nontextured membrane with a most rough surface in which a thick biofilm was observed. Real-time PCR quantification revealed significantly greater adhesion of C. albicans cells to PTFE membranes than the control membrane (p ≤ .001) with the membranes having a textured surface exhibiting the highest count of 2680 × 104 cells/ml compared to the count of 707 × 104 cells/mL on those with a nontextured one (p ≤ .001). One membrane with nontextured surface, but with most rough surface was found to exhibit the highest count of 3010 × 104 cells/ml (p ≤ .05). CONCLUSION: The results of this study indicate that C. albicans adhesion on membranes' surfaces depends on the degree of surface roughness and/or on the presence of a texture. Textured PTFE membranes and/or membranes high roughness showed significantly more adhered C. albicans cells. These findings can impact the surgeon's choice of GBR membrane and postoperative maintenance.

New bone formation around xenogenic dentin grafts to rabbit tibia marrow.

PURPOSE: From traumatology, it is well known that dentoalveolar ankylosis results in osseous replacement and formation of new bone. This principle is used after decoronation for preservation of the height and width of the alveolar bone crest after trauma. Dentin possesses bone-forming properties and may possibly also be used as a bone augmentation material prior to implant placement. The aim of this study was to investigate whether xenogenic dentin particles inserted into the marrow space of rabbit tibia, a space where there is no solid bone tissue initially, would contribute to new bone formation. MATERIALS AND METHODS: Dentin chips from human teeth were inserted into tibias of ten New Zealand rabbits. The tibial bones were processed for histology after 6 months, and new bone formation was quantified. RESULTS: Bone formation was ranging from 0 to 86% on the dentin fragments, and there was minor inflammation. Bone formation was seen to a larger extent on dentin grafts located close to the native tibial bone wall. There was a significant correlation (r = -0.579, P < 0.001) between the amount of bone formation around the dentin graft and distance to the tibial cortical wall. CONCLUSION: Dentin promotes new bone formation when located close to native cortical bone and may have a potential as a bone augmentation material.

Comparison of Radiographic and Clinical Status and Peri-implant Crevicular Fluid Prostaglandin E2 Levels Among Patients with Peri-implant Mucositis and Peri-implantitis.

The aim of this study was to compare radiographic and clinical status and peri-implant sulcular fluid (PISF) prostaglandin E2 (PGE2) levels among patients with and without peri-implant disease. Patients with peri-implant mucositis (PiM) (Group 1) and peri-implantitis (Group 2) and individuals without peri-implant disease (Group 3) were included. Demographic information was collected, and peri-implant modified plaque and bleeding indices (mPI and mBI), probing depth (PD), and crestal bone loss (CBL) were recorded. PISF samples were collected and PGE2 levels measured. Statistical significance was set at P < .01. A total of 22 patients with PiM, 22 with peri-implantitis, and 23 without peri-implant disease (controls) were included. Scores of mPI (P < .01), mBI (P < .01), and PD (P < .01) were higher in patients with PiM and peri-implantitis than the controls. The volumes of collected PISF were significantly higher in patients with peri-implantitis (P < .01) compared to patients with PiM and the controls. The PISF volume was significantly higher in PiM patients (P < .01) than in the controls. There was a significant correlation between peri-implant PD and PISF PGE2 levels in patients with peri-implantitis (P < .001). Raised PISF PGE2 levels indicate poor peri-implant health; therefore, PGE2 is a potential biomarker for the assessment of peri-implant health status.

Differences in Mechanical and Physicochemical Properties of Several PTFE Membranes Used in Guided Bone Regeneration.

Non-resorbable PTFE membranes are frequently used in dental-guided bone regeneration (GBR). However, there is a lack of detailed comparative studies that define variations among commonly used PTFE membranes in daily dental clinical practice. The aim of this study was to examine differences in physicochemical and mechanical properties of several recent commercial PTFE membranes for dental GBR (CytoplastTM TXT-200, permamem®, NeoGen®, Surgitime, OsseoGuard®-TXT, OsseoGuard®-NTXT). Such differences have been rarely recorded so far, which might be a reason for the varied clinical results. For that reason, we analyzed their surface architecture, chemical composition, tensile strength, Young's modulus, wettability, roughness, density, thickness and porosity. SEM revealed different microarchitectures among the non-textured membranes; the textured ones had hexagonal indentations and XPS indicated an identical spectral portfolio in all membranes. NeoGen® was determined to be the strongest and OsseoGuard®-TXT was the most elastic. Wettability and roughness were highest for Surgitime but lowest for OsseoGuard®-NTXT. Furthermore, permamem® was the thinnest and NeoGen® was identified as the thickest investigated GBR membrane. The defect volumes and defect volume ratio (%) varied significantly, indicating that permamem® had the least imperfect structure, followed by NeoGen® and then Cytoplast TM TXT-200. These differences may potentially affect the clinical outcomes of dental GBR procedures.

Dental Education in an Era of COVID-19: Kuwait's Experience.

The coronavirus disease 2019 (COVID-19) pandemic has had a significant impact on dental education worldwide. Due to the rapid spread of COVID-19 across Kuwait, it was essential for the Faculty of Dentistry (FoD) at Kuwait University to make appropriate modifications to the functioning of the dental school. The FoD's goal was not only to ensure a safe environment for its staff, students, and patients but also to sustain the students' academic progression. The FoD adopted several measures including the establishment of a COVID-19 response team, adoption of a blended-learning model, and phase-wise re-opening of the dental center. This paper discusses on the strategies that the FoD adopted, in response to the challenges posed by the pandemic.

Integration of Dental Implants in Conjunction with EDTA-Conditioned Dentin Grafts: An Experimental Study.

This study was undertaken to investigate the integration of titanium micro-implants installed in conjunction with previously dentin-grafted areas and to study the morphological appearance, mineral content, and healing pattern of xenogenic EDTA-conditioned dentin blocks and granules grafted to cavities in the tibial bone of rabbits. Demineralized and non-demineralized dentin blocks and granules from human premolars were implanted into cavities prepared on the lateral aspects of the tibias of rabbits. After a healing period of six months, micro-implants were installed at each surgical site. Histological examinations were carried out after 24 weeks. Characterization of the EDTA-conditioned dentin blocks was performed by means of light microscopy, dental X-rays, scanning electron microscopy, and energy dispersive X-ray analysis (EDX). No implants were found to be integrated in direct contact with the dentin particles or blocks. On the EDTA-conditioned dentin surface, the organic marker elements C and N dominated, as revealed by EDX. The hydroxyapatite constituents Ca and P were almost absent on the dentin surface. No statistically significant difference was observed between the EDTA-conditioned and non-demineralized dentin, as revealed by BIC and BA. The bone-inductive capacity of the dentin material seemed limited, although demineralization by means of EDTA indicated higher BIC and BA values in conjunction with the installed implants in the area. A 12 h EDTA treatment did not fully decalcify the grafts, as revealed by X-ray analysis.

Highly Segregated Biocomposite Membrane as a Functionally Graded Template for Periodontal Tissue Regeneration.

Guided tissue regeneration (GTR) membranes are used for treating chronic periodontal lesions with the aim of regenerating lost periodontal attachment. Spatially designed functionally graded bioactive membranes with surface core layers have been proposed as the next generation of GTR membranes. Composite formulations of biopolymer and bioceramic have the potential to meet these criteria. Chitosan has emerged as a well-known biopolymer for use in tissue engineering applications due to its properties of degradation, cytotoxicity and antimicrobial nature. Hydroxyapatite is an essential component of the mineral phase of bone. This study developed a GTR membrane with an ideal chitosan to hydroxyapatite ratio with adequate molecular weight. Membranes were fabricated using solvent casting with low and medium molecular weights of chitosan. They were rigorously characterised with scanning electron microscopy, Fourier transform infrared spectroscopy in conjunction with photoacoustic sampling accessory (FTIR-PAS), swelling ratio, degradation profile, mechanical tensile testing and cytotoxicity using human osteosarcoma and mesenchymal progenitor cells. Scanning electron microscopy showed two different features with 70% HA at the bottom surface packed tightly together, with high distinction of CH from HA. FTIR showed distinct chitosan dominance on top and hydroxyapatite on the bottom surface. Membranes with medium molecular weight showed higher swelling and longer degradation profile as compared to low molecular weight. Cytotoxicity results indicated that the low molecular weight membrane with 30% chitosan and 70% hydroxyapatite showed higher viability with time. Results suggest that this highly segregated bilayer membrane shows promising potential to be adapted as a surface layer whilst constructing a functionally graded GTR membrane on its own and for other biomedical applications.

Tooth-implant connection with fixed partial dentures in partially edentulous arches. A retrospective cohort study over an 11.8 year observation period.

BACKGROUND: The fixed tooth-implant connection remains a controversial issue. This private practice-based retrospective study aimed to evaluate the clinical outcomes of a contemporary fixed partial denture (FPD) design for connecting natural teeth and implants (TI-FPD), over an 11.8 years observation period. MATERIAL AND METHODS: The data of 91 partially edentulous patients (44 males and 47 females, mean age of 47.7 years) treated with a newly designed TI-FPD retained on 1 implant and 1 natural tooth were analyzed retrospectively. Teeth were covered with electroformed copings and a CAD/CAM made bridge was fixed over the abutments with provisional cement. Two different implant systems were used: Camlog (N=22; anterior areas) and Straumann tissue level (N=69; posterior areas). RESULTS: The survival rate for both implants and teeth was 100%. 19/21 (90%, 95%CI 82-95%), 16/21 (66%, 95%CI 66-84%), and 16/21 (66%, 95%CI 66-84%) patients were free of biological complications after 5 years, 10 years, and 15 years post-loading, respectively. 23/35 (90%, 95%CI 54-74%), 21/35 (61%, 95%CI 50-70%), and 21/35 (61%, 95%CI 50-70%) were free of technical complications following 5 years, 10 years, and 15 years post loading, respectively. CONCLUSIONS: Despite limitations of the study, the findings demonstrated that the use of a recently designed TI-FPD could be used for the tooth-implant connection in cases of partial edentulism and this may widen the treatment modalities by reducing the cost and need for extensive bone tissue augmentations. Further controlled longitudinal studies with larger patient groups are needed. Key words:Tooth-implant connection, dental implant, fixed partial dentures, complications, implant prosthodontics.

Peri-Implant Mucosa Augmentation with an Acellular Collagen Matrix.

Peri-implant keratinized mucosa (PI-KM) may support implant survival. Acellular collagen matrices (aCMs) have been widely used to facilitate soft tissue regeneration. The aim of this study was to investigate clinical outcomes obtained with the use of an aCM (mucoderm®) to enhance PI-KM. In this retrospective non-randomized case series, 27 restored implants in 14 patients (eight males and six females, mean age = 56 years) with a PI-KM width ≤ 1 mm were followed for 6 months. It was demonstrated that aCM grafts augmented PI-KM effectively (mean increase of 5.4 mm; >533%) without a significant change in bleeding on probing (BOP) from baseline. The mean aCM shrinkage was 3.9 mm (42%). Gender, area, arch, and BOP did not influence PI-KM augmentation or aCM shrinkage significantly. The present results demonstrated that the examined aCM was effective and predictable for attaining a band of keratinized tissue, while avoiding graft donor site harversting.

Postoperative infection after surgical removal of impacted mandibular third molars: an analysis of 110 consecutive procedures.

OBJECTIVE: The aim of this study was to evaluate the rate of postoperative infection and other complications after the surgical removal of impacted mandibular third molars. SUBJECTS AND MATERIALS: Medical records of 110 consecutive patients with 130 consecutive surgical extractions of impacted lower third molar teeth performed under local anesthetic using strict aseptic techniques were reviewed and analyzed. No systemic antibiotics were administered or prescribed after the surgery. The rates of postoperative infection and other complications were evaluated clinically. RESULTS: Of the 130 surgical removals, 110 in 90 patients met the inclusion criterion of nonuse of antibiotics. Fifty-nine were female and the remaining 31 were male. Average age was 25.2 years. Of the 110 surgeries, postoperative infection occurred in 6 (5.5%). Other complications were alveolar osteitis (n = 9, 8.2%), pain lasting more than 1 week (n = 5, 4.3%) and sensory dysfunction of the inferior alveolar nerve (n = 2,0.8%). CONCLUSION: The low rates of postoperative infection and other complications observed in this study encouraged us to continue surgical removal of impacted mandibular third molars without routine prescription of antibiotics unless indicated for other medical reasons.

Bone regeneration in rabbit calvarial critical-sized defects filled with composite in situ formed xenogenic dentin and biphasic tricalcium phosphate/hyroxyapatite mixture.

The purpose of this study was to evaluate bone healing in calvarial defects using two bone graft substitute materials; biphasic beta-tricalcium phosphate/hydroxyapatite in hydrogel (ß-TCP/HA) versus composite non-demineralized xenogenic dentin with ß-TCP/HA mixture. Full thickness critical-sized defects were created bilaterally in 10 New Zealand male rabbits. Seven defects were left empty, six filled with biphasic tricalcium phosphate putty, and seven were filled with composite non-demineralized xenogenic dentin with biphasic tricalcium phosphate. Animals were sacrificed at eight weeks postoperatively and the healing of the biomaterial-filled defects was compared radiographically and by histomorphometry. Micro-computed tomography (µCT) was utilized to analyze the osteogenesis and healing patterns of the defects. Quantitative analysis of volume fraction (%) of the newly formed bone and remaining graft material (FV=filling volume/TV=tissue volume) and mean intensity [HU] in the defects were evaluated. Defects filled with composite dentin with biphasic tri-calcium phosphate showed volume fraction (FV/TV) in the order of 55.81% ± 17.72%, whereas defects filled with only biphasic tricalcium phosphate showed a fraction of 39.84% ± 16.06%, which represent the ratio of remaining graft material and new bone formation to the tissue volume. The empty negative control defects showed a volume fraction of 19.14% ± 8.787%. Histological analysis showed significant percentage increase in bone formation and residual graft with the composite Dentin/ß-TCP group after 8 weeks. The findings suggest that composite xenogenic dentin with biphasic tricalcium phosphate showed improved osteogenesis when compared to biphasic tricalcium phosphate without the addition of non-demineralized dentin. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 773-782, 2019.

The effect of a leaflet given to parents for first aid measures after tooth avulsion.

The aims of this study were to evaluate knowledge level among parents regarding tooth avulsion and replantation and to evaluate a simple leaflet as an information tool to enhance this knowledge. One Hundred and fifty parents in a primary school in Kuwait City participated in the study. Half of the parents received a leaflet with basic first aid message regarding what to do in case of tooth avulsion. One week after reading the leaflet, the parents who had received the leaflet were evaluated by using a questionnaire. The other half of the parents who had not seen the leaflet served as control. The level of knowledge was measured in the following categories: General knowledge of tooth avulsion, knowledge of replantation and primary vs permanent teeth, knowledge of how to clean an avulsed tooth, knowledge of extra-oral time, knowledge of storage methods and storage media. By scoring the knowledge, the level of knowledge was calculated. The results showed that knowledge level was low among Kuwaiti parents. Improvement was seen in all categories of knowledge as a result of reading the leaflet. A simple leaflet can be a valuable tool to convey important basic information and enhance knowledge of tooth avulsion and how parents should act in such a situation, although there are limitations in conveying the message for a complete understanding. Measuring the knowledge by scoring can give valuable feedback in developing various educational tools.

Comparison of radiographic bone height assessments in panoramic and intraoral radiographs of implant patients.

PURPOSE: To compare the ability of 2 radiographic methods, intraoral and panoramic radiography, commonly used in private practices following implant treatment to provide reliable information about the level of peri-implant marginal bone. An additional aim was to compare the inter- and intraobserver reliability. MATERIALS AND METHODS: Patients with implants placed in the mandible in 10 private practices were studied retrospectively. Postoperative intraoral and panoramic radiographs were evaluated at a university oral radiology clinic. Two observers, a specialist in oral and maxillofacial radiology and a specialist in oral and maxillofacial surgery, assessed the bone level, and the thread at which the marginal bone seemed to be attached was registered for the distal and mesial surfaces of all implants at 2 assessments several weeks apart. Kappa statistics was used to compare the agreement between assessments, observers, and methods of radiography. RESULTS: Intraobserver agreement was good or very good, while interobserver agreement was predominantly moderate. The agreement rate between the methods was also moderate. Seven percent of the sites were not possible to assess, with a small difference in favor for panoramic radiographs. In the assessment of the panoramic radiographs, the radiologist found more sites too difficult to assess than the surgeon did. CONCLUSIONS: In this study, panoramic radiographs were found to be as reliable as conventional intraoral radiographs when used to assess the point of bone attachment to implant threads. Intra- and interobserver agreement were reliable but not excellent. The radiologist was more successful in finding sites where the bone level was impossible to assess accurately.

The incidence of lung cancer in the Gulf Cooperation Council countries.

BACKGROUND: Lung cancer is the most common cancer in the world, with an estimated number of 1.3 million new cases as of 2002. This is the first report from the countries that comprise the Gulf Cooperation Council (GCC). PATIENTS AND METHODS: All the primary lung cancer cases registered in the Gulf Center for Cancer Registration during 1998 to 2001 were used to calculate the age-standardized incidence rate (ASR) per 100,000 person-years by the direct standardization method. RESULTS: Overall, there were 1607 (1261 males, 346 females) primary lung cancer cases registered during this period with the male to female ratio of 3.6:1. The highest ASR was in Bahrain (34.3 for males, 12.1 for females) followed by Qatar (18.5 for males, 5.5 for females) and Kuwait (13.8 for males, 4.0 for females); the lowest rate was in Saudi Arabia (4.8 for males, 1.3 for females). The mean age at diagnosis for males ranged from 68.7 years in Bahrain to 59.2 years in Oman. For females it ranged from 68.2 years in Bahrain to 58.0 years in Oman. Squamous cell carcinoma in males (except in Qatar) and adenocarcinoma in females were the predominant histological type. CONCLUSIONS: Cancer of the lung is one of the common cancers among males in all the GCC countries and ranks second among Bahraini females. Adenocarcinomas were more common in women than men.

Histologic analysis of a novel extracellullar matrix membrane for guided bone regeneration: an experimental study in rabbits.

This experiment was conducted to study the histologic feasibility and biologic impact of Ti02 impregnation of an extracellullar matrix (ECM) membrane in guided bone regeneration. Eighteen adult New Zealand White rabbits were used. Bilateral bone defects were created in edentulous areas of the maxilla. The defects were filled with demineralized freeze-dried bone (DFDB). ECM was randomly pretreated with a suspension containing saline and 3 mg Ti02 granules. A regular ECM membrane served as a control on the contralateral side. Healing periods were 2, 4, and 8 weeks. Histologic and histomorphometric analyses were performed. The parameters assessed were (1) zone of inflammatory cells adjacent to ECM membrane, (2) presence of cellullar ingrowth into ECM, and (3) presence of Ti02 particles within the ECM barrier membrane. In general, no adverse reactions toward both groups of ECM membranes could be noted. The Ti02 particles remained within the ECM after 8 weeks of healing, making histologic detection of ECM easy. Histomorphometric analysis revealed low numbers of inflammatory cells adjacent to the ECM surface and adequate preservation and integration of the barrier. Contrasting Ti02 particles impregnated into the ECM membrane can be a very useful tool for the detection of similar biologic materials in in vivo models.