Hepatitis B genotypes： Relation to clinical outcome in patients with chronic hepatitis B in Saudi Arabia

INTRODUCTION Hepatitis B virus (HBV) infection is a global health problem with over 350 million chronic carriers of the virus with the risk of developing chronic hepatitis, cirrhosis or hepatocellular carcinoma (HCC). HBV is a circular, partially double-s…     

Seroepidemiology of Hepatitis B virus infection in Saudi children 8 years after a mass hepatitis B vaccination programme

OBJECTIVES: On October 1 1989, a programme was begun in Saudi Arabia in which the HBV vaccine was added as the 'seventh' primary immunogen of the Extended Programme of Immunization (EPI). In 1990, another programme was launched by the Ministry of Health to vaccinate all school children. Eight years after this mass vaccination programme, the efficacy of HBV vaccine was evaluated in a community-based study. METHODS: A community-based study was carried out in Saudi children in urban and rural areas, covering all the regions of Saudi Arabia. After informed consent, blood samples were obtained and tested for HBV markers. RESULTS: Among 4791 vaccinated Saudi children aged 1-12 years, only 15 were found to be HbsAg-positive (0.31%). HbsAg-positivity was 0.16% in children vaccinated at birth compared with 0.7% in those vaccinated at school entry. The overall HbsAg carrier rate dropped from 6.7% in 1989 to 0.3% in 1997 (P<0.00001). Similarly, there was a significant reduction in the prevalence of anti-HBc from 4.2% in 1989 to 0.46% in 1997 (P<0.00001). The overall seroconversion rate to HB vaccine among 4087 Saudi children up to 12 years of age was about 77%. Seroconversion rate in those vaccinated at birth was 77% compared with 71% in those vaccinated at school entry. After 8 years of receiving the third vaccine dose, close to 65% of the children had an anti-HBs titre of more than 10 IU/l compared with about 28% who had an anti-HBs titre of more than 100 IU/l after the same period. CONCLUSION: The result of this study demonstrates the tremendous impact of the mass HB vaccination programme on the seroepidemiology of HBV infection in Saudi Arabia. The ultimate goal of preventing HBV-related chronic liver disease and hepatocellular carcinoma in Saudi Arabia is foreseeable in the near future.     

The impact of introduction of Code-STEMI program on the reduction of door-to-balloon time in acute ST-elevation myocardial infarction patients undergoing primary percutaneous coronary intervention: A single-center study in Saudi Arabia

Objectives

This study was conducted to evaluate the effect of direct emergency department activation of the catheterization lab on door-to-balloon time (D2BT) and outcomes of acute ST-elevation myocardial infarction (STEMI) patients at a major tertiary care hospital in Riyadh, Saudi Arabia.

A comparative study of 2 methods for obtaining platelet-rich plasma.

PURPOSE: Double and single centrifugation are the most commonly used techniques for obtaining platelet-rich plasma (PRP) in dentistry. In this study, we used and compared 2 methods for obtaining PRP: double centrifugation (ACE system; Surgical Supply and Surgical Science Systems, Brockton, MA) and single centrifugation (Nahita system; Nahita, Navarra, Spain). MATERIALS AND METHODS: Blood samples were obtained from 30 random patients. Each blood sample was treated using the ACE system and Nahita system methods, after which the obtained material was analyzed by flow cytometry for platelet counts and by transmission electron microscopy (TEM) for ultrastructural analysis of the PRP gel. RESULTS: Platelet count analysis of the PRP obtained from both methods revealed that the ACE and Nahita systems accomplished platelet concentrations of (336%) and (227%), respectively. The platelet counting results obtained from the ACE system samples were more dispersed than their Nahita system counterpart. The ultrastructural (ie, TEM) study showed considerable alterations of the platelet aggregates in the ACE's PRP, especially when the samples were not mixed in the final stage of the procedure, whereas the Nahita aggregates always had a normal physiological appearance. CONCLUSIONS: The ACE double-centrifugation method is able to achieve higher platelet concentrations than the single-centrifugation Nahita system, although the results obtained by ACE were more dispersed. Nevertheless, the ACE system provoked alterations in the PRP ultrastructure, and it was more sensitive to small errors during preparation.     

Bone augmentation in rabbit calvariae: comparative study between Bio-Oss and a novel beta-TCP/DCPD granulate

AIM: In the present in vivo study, we compare the bone regeneration capacity of a novel brushite cement synthesized in our laboratory (DTG) with Bio-Oss using rabbits as an animal model. METHODS: The study was performed in a group of 14 adult New Zealand rabbits using the bone conduction model. Two titanium cylinders were fixed into perforated slits made on the parietal cortical bone of each rabbit. One cylinder was left empty (negative control) and the other was filled with either Bio-Oss or brushite set-cement granules (test cylinder). Four weeks after the intervention, the animals were sacrificed and biopsies were taken. The following parameters were analysed: bone tissue augmentation, bone mineral density and biomaterial resorption. The comparison of data between the different groups was performed using the Mann-Whitney test with a significance level of p<0.05. RESULTS: The mean bone mineral density and augmented mineral tissue inside the test cylinders were similar but higher than those of negative controls. Material resorption and bone tissue augmentation were significantly higher in the defects treated with the brushite-based set cement (p<0.05). CONCLUSIONS: Brushite cement granules were more resorbable and generated more bone tissue than Bio-Oss inside the titanium cylinders placed in the rabbit calvaria.     

Sensitivity and Specificity of Radiographic Methods for Predicting Insertion Torque of Dental Implants

Background: Subjective radiographic classifications of alveolar bone have been proposed and correlated with implant insertion torque (IT). The present diagnostic study aims to identify quantitative bone features influencing IT and to use these findings to develop an objective radiographic classification for predicting IT. Methods: Demographics, panoramic radiographs (taken at the beginning of dental treatment), and cone‐beam computed tomographic scans (taken for implant surgical planning) of 25 patients receiving 31 implants were analyzed. Bone samples retrieved from implant sites were assessed with dual x‐ray absorptiometry, microcomputed tomography, and histology. Odds ratio, sensitivity, and specificity of all variables to predict high peak IT were assessed. Results: A ridge cortical thickness >0.75 mm and a normal appearance of the inferior mandibular cortex were the most sensitive variables for predicting high peak IT (87.5% and 75%, respectively). A classification based on the combination of both variables presented high sensitivity (90.9%) and specificity (100%) for predicting IT. Conclusions: Within the limitations of this study, the results suggest that it is possible to predict IT accurately based on radiographic findings of the patient. This could be useful in the treatment plan of immediate loading cases.     

Bond strength of self-adhesive resin cements to tooth structure

Objectives

The aim of this study was to evaluate the strength of the bond between newly introduced self-adhesive resin cements and tooth structures (i.e., enamel and dentin).

Methods

Three self-adhesive cements (SmartCem2, RelyX Unicem, seT SDI) were tested. Cylindrical-shaped cement specimens (diameter, 3 mm; height, 3 mm) were bonded to enamel and dentin. Test specimens were incubated at 37 °C for 24 h. The shear bond strength (SBS) was tested in a Zwick Roll testing machine. Results were analyzed by one-way ANOVA and t-test. Statistically significant differences were defined at the α = 0.05 level. Bond failures were categorized as adhesive, cohesive, or mixed.

Results

The SBS values ranged from 3.76 to 6.81 MPa for cements bonded to enamel and from 4.48 to 5.94 MPa for cements bonded to dentin (p > 0.05 between surfaces). There were no statistically significant differences between the SBS values to enamel versus dentin for any given cement type. All cements exhibited adhesive failure at the resin/tooth interface.

Conclusions

Regardless of their clinical simplicity, the self-adhesive resin cements examined in this study exhibit limited bond performance to tooth structures; therefore, these cements must be used with caution.     

Effect of grafting materials on osseointegration of dental implants surrounded by circumferential bone defects. An experimental study in the dog

Aims: This study was designed to evaluate the effect of gap width and graft placement on bone healing around implants placed into simulated extraction sockets in the mandibles of four beagle dogs. Materials and methods: Four Ti‐Unite^® implants (13 mm × 3.3 mm) were placed on each side of the mandible. Three implants were surrounded by a 1.35 mm circumferential and a 5 mm deep gap around the coronal portion of the implants. A fourth implant was inserted conventionally into both sides of the mandibles as a positive control. The gaps were filled with either Bio‐Oss^®, autogenous bone or with a blood clot alone. The study design was balanced for animal, side and modality. Ground sections were prepared from biopsies taken at 3 months, and computer‐aided histometric measurements of bone/implant contact and area of bone within threads were made for the coronal 5 mm. Data were analysed using analysis of variance. Results: The mean bone/implant contact was 9.8 mm for the control and ranged from 9.3 to 11.3 mm for the three test modalities. The corresponding values for area within threads were 1 mm² and 1–1.2 mm². Modality had a significant effect on both bone/implant contact (F=16.9; P<0.0001) and area within threads (F=16.7; P<0.0001). Conclusion: The results of this study suggest that both autogenous bone graft and Bio‐Oss^® played an important role in the amount of hard tissue fill and osseointegration occurring within marginal bone defects around implants.     

Oro-dental and cranio-facial characteristics of osteogenesis imperfecta type V

Osteogenesis imperfecta (OI) type V is an ultrarare heritable bone disorder caused by the heterozygous c.-14C > T mutation in IFITM5. The oro-dental and craniofacial phenotype has not been described in detail, which we therefore undertook to evaluate in a multicenter study (Brittle Bone Disease Consortium). Fourteen individuals with OI type V (age 3–50 years; 10 females, 4 males) underwent dental and craniofacial assessment. None of the individuals had dentinogenesis imperfecta. Six of the 9 study participants (66%) for whom panoramic radiographs were obtained had at least one missing tooth (range 1–9). Class II molar occlusion was present in 8 (57%) of the 14 study participants. The facial profile was retrusive and lower face height was decreased in 8 (57%) individuals. Cephalometry, performed in three study participants, revealed a severely retrusive maxilla and mandible, and moderately to severly retroclined incisors in a 14-year old girl, a protrusive maxilla and a retrusive mandible in a 14-year old boy. Cone beam computed tomograpy scans were obtained from two study participants and demonstrated intervertebral disc calcification at the C2-C3 level in one individual. Our study observed that OI type V is associated with missing permanent teeth, especially permanent premolar, but not with dentinogenesis imperfecta. The pattern of craniofacial abnormalities in OI type V thus differs from that in other severe OI types, such as OI type III and IV, and could be described as a bimaxillary retrusive malocclusion with reduced lower face height and multiple missing teeth.