Prevalence of distal surface caries in the second molar among referrals for assessment of third molars: a systematic review and meta-analysis.

We conducted a systematic review of epidemiological studies to assess the prevalence of distal surface caries (DSC) in second molars adjacent to third molars. We searched the Cochrane Library, Lilacs, Embase, and Medline through Ovid® (Wolters Kluwer) to retrieve English and non-English papers from inception to June 2016, and supplemented this with a search of the references and by tracking citations. Three reviewers contributed: one reviewed all the papers, and the other two divided the rest between them. They extracted data, completed structured quality assessments with a validated risk of bias tool for observational studies, and categorised the summary scores. The search yielded 81 records and 11 studies were analysed. The considerable methodological diversity meant that five were not eligible for inclusion in the quantitative synthesis. A meta-analysis of six studies on the prevalence of DSC and a subgroup analysis of three on various third-molar angulations were indicated. The overall pooled prevalence estimate calculated with a random-effects model was 23% (95% CI 2% to 44%) among patients. Prevalence subtotals were 20% (95% CI 5% to 36%) for prospective, and 15% (95% CI 5% to 36%) for retrospective studies among teeth. A subgroup analysis of three studies with 1296 patients (1666 molars) yielded a prevalence of DSC of 36% (95% CI 5% to 67%) for mesial impactions and 22% (95% CI 1% to 42%) for horizontal impactions. DSC was present in 3% of distally-inclined impactions, (95% CI 1% to 5%) and in 7% (95% CI 1% to 13%) of vertical third molars. The studies varied. The risk of bias was low in one and moderate in two. European studies suggested that DSC may be present in about one in four referrals for the assessment of third molars, and that the risk is considerably higher in those with convergent third molar impactions.

Detecting the earliest radiological signs of bisphosphonate-related osteonecrosis.

Introduction Oral bisphosphonates are the most commonly prescribed anti-resorptive drugs used in the treatment of osteoporosis, but osteonecrosis of the jaw is a serious complication. The early diagnosis of this destructive side effect is crucial in preventing excessive bone loss, pain and infection.Objective To aid dental practitioners in the early identification of bisphosphonate-related osteonecrosis of the jaw.Method A scoping review was carried out.Data sources We searched MEDLINE via OVID, EMBASE via OVID, Dentistry and Oral Sciences Source (DOSS), Proquest Dissertation and Theses Search, to identify references that described clinical and radiological findings in medication-related osteonecrosis of the jaw (MRONJ).Data selection Nineteen references mentioned the earliest radiological changes in MRONJ with a description of the observations and were included in the analysis.Data synthesis The radiographic signs included osteosclerosis/lysis, widening of the periodontal ligament and thickening of the lamina dura and cortex. To assess the quality of original data on which recommendations had been made, these 19 studies were subjected to a quality appraisal.Conclusion Using bone exposure as a criterion for diagnosis of MRONJ, leads to delayed diagnosis and a poor response to treatment. In those patients at risk of bone exposure with MRONJ, insufficient information is present in the literature to allow the general dental practitioner to reliably identify the radiographic features indicating imminent bone exposure. A well-designed prospective study is needed.

Guidelines on the timing and frequency of bitewing radiography: a systematic review.

Objectives To identify guidelines on when and how frequently bitewing radiographs should be used in dentistry for the diagnosis of caries, and to provide an objective appraisal of their quality.Data sources MEDLINE (OVID), US National Guideline Clearinghouse (www.guideline.gov) and the Royal College of Surgeons of England (https://www.rcseng.ac.uk/fds/publications-clinical-guidelines/clinical_guidelines) websites were searched using a variety of relevant search terms (2 August 2016).Data selection Publications were included if they made recommendations on the issue of when and how frequently radiographs should be used in any dentally-related specialty pertaining to the diagnosis of caries; and/or if they were aimed at the individual practitioner (any health professional working within dentistry) and/or patients.Data analysis Thirteen published guidelines were included and assessed using the AGREE II instrument.Conclusions There was a significant variation amongst the guidelines in the recommendations at what age radiography should be undertaken. There was also disagreement on the frequency of repeat radiographs and how this is influenced by the age of the patient and their caries risk.

Hospital-associated transmission of Brucella melitensis outside the laboratory.

Brucella melitensis was identified in an aspirate obtained from a patient's hip joint during a procedure at a hospital in Canada. We conducted an investigation into possible exposures among hospital workers; 1 worker who assisted with the procedure tested positive for B. melitensis. Aerosol-generating procedures performed outside the laboratory may facilitate transmission of this bacterium.

The impact of premature birth on the mandibular cortical bone of children.

SUMMARY: Children born prematurely often have reduced skeletal mineralization. The aim in this study was to compare the cortical thickness of the lower jaw on radiographs of 8- to 10-year-old children with histories of preterm or full term births. There were no significant differences in cortical thickness between full term and preterm children at this age. INTRODUCTION: The purpose of this study was to compare the cortical thickness of the mandible on panoramic radiographs of 8- to 10-year-old children with histories of preterm or full term births. METHODS: Panoramic radiography was performed on 36 extremely preterm, 38 very preterm and 42 full term children at the age of 8 to 10 years. Five observers independently measured the mandibular cortical width on the panoramic radiographs at four defined sites bilaterally. Altogether, 928 sites were available. Measurements were performed twice on a random 24% of the sites by four observers. One-way analysis of variance with Tukey's post hoc test was used to test differences between groups. Intraclass correlation coefficient (ICC) was calculated for interobserver agreement while intra-observer agreement was expressed as measurement precision. RESULTS: Significant differences of mandibular cortical width were found between extremely preterm and very preterm children for five of the eight measurement sites with the very preterm showing the highest value. No significant differences were found between full term and either very preterm or extremely preterm except for one measurement site, with the extremely preterm showing the lowest value. ICC varied between 0.30 and 0.83 for the different sites (mean 0.62). The precision of a single measurement varied between 0.11 and 0.45 mm (mean 0.25 mm). CONCLUSIONS: From the evidence that very preterm children had significantly thicker mandibular cortices than extremely preterm children, we suggest that these findings may reflect the effect of mineral supplementation provided to premature infants, causing a 'shifting up' of bone mineral status relative to the full term peer group while maintaining the difference between very preterm and extremely preterm born children.

Water sorption and solubility of core build-up materials.

OBJECTIVES: To investigate the variation in water sorption and solubility across a range of different core build-up materials. METHODS: Five materials were tested, four of which are resin-based materials (Grandio Core, Core.X Flow, Bright Flow Core, Speedee) and one resin-modified glass ionomer (Fuji II LC). All specimens (n=10) were immersed in 10ml distilled water in individual glass containers and weighed at one week, 14 and 28 days. After a total immersion time of 28 days, 7 specimens were dried to a constant mass, in a desiccator for 28 days. Three samples of each material were not dried, but were left in distilled water for 1 year, to determine the long-term water sorption properties. Specimens were weighed at monthly intervals until 6 months and then at the 9th and 12th months. Each specimen was measured using a digital electronic caliper (Mitutoyo Corporation, Japan). RESULTS: After 28 days immersion, the change in water sorption and solubility of the materials ranged from 12.9 to 67.1µg/mm(3) (P<0.001) and 0.9-6.4µg/mm(3) respectively (P<0.001). Except for Fuji II LC, an independent T-test showed significantly higher water sorption and solubility for the other materials after 1-year total immersion in water compared to 1 month (P<0.05). Using repeated measures ANOVA, all materials showed mass changes over time (1 month) (P<0.001). SIGNIFICANCE: Grandio Core had the lowest water sorption and solubility among the tested materials. According to the ISO 4049 standards, all the tested materials showed acceptable water sorption and solubility, apart from the water sorption behavior of Fuji II LC.

An observational study to assess the association between osteoporosis and periodontal disease.

BACKGROUND: There is evidence to suggest osteoporosis may result in premature tooth loss. The pathology behind this relationship is poorly understood. A correlation with osteoporosis and greater susceptibility to periodontal disease has been suggested. OBJECTIVES: To investigate the association between osteoporosis and periodontal disease, accounting for the effect of confounding variables of age, smoking status and oral hygiene.Setting Three hundred and fifty-nine postmenopausal women aged 45-70 years were recruited from the Greater Manchester area between March 2008 and June 2010.Subjects and methods Data were collected on osteoporosis status, smoking status, pocket probing depths, suppuration, plaque, bleeding and calculus indices. Dental panoramic tomographs were taken and periodontal bone support assessed on all teeth. Data were analysed using SPSS software (version 20). RESULTS: Complete data were available for 348 patients. Twenty-six percent (91) of individuals were osteoporotic. Logistic regression was used. The relationship between osteoporosis status and moderate to severe periodontal disease of both molar teeth and the whole mouth was not significant (p = 0.088 and p = 0.296 respectively). CONCLUSIONS: Osteoporosis is not a causal factor in the development of moderate to severe chronic periodontitis.

Tooth loss and osteoporosis: to assess the association between osteoporosis status and tooth number.

BACKGROUND: Osteopenia and osteoporosis are conditions characterised by a reduction in bone mineral density. There is contradictory evidence whether osteoporotic patients have greater tooth loss than non-osteoporotic patients. OBJECTIVE: To investigate the association between tooth number and osteoporotic status, taking into account the effect of other confounding variables such as age, smoking status, alcohol consumption and the use of hormone replacement therapy. SETTING: Three hundred and fifty-nine patients were recruited from the Manchester region between March 2008 and June 2010. SUBJECTS AND METHODS: Data were collected on osteoporotic status, smoking status, alcohol consumption, age and the use of hormone replacement therapy. Dental panoramic tomographs were taken for each patient and the teeth present were charted and counted. Data were analysed using SPSS software (version 19). RESULTS: Complete data was available for 333 patients. Twenty-seven percent of individuals (90) were classified as osteoporotic. There was a significant relationship between molar tooth number and osteoporotic status (p = 0.017, 95% CI -1.339 to -0.137). CONCLUSION: Clinicians should inform osteoporotic patients they may be at greater risk of tooth loss and instigate more intensive preventive regimens for these individuals.

Do patients with osteoporosis have an increased prevalence of periodontal disease? A cross-sectional study.

UNLABELLED: The study examined if women with osteoporosis were at increased risk of periodontal disease. Three hundred eighty females aged 45-65 years with recent dual-energy X-ray absorptiometry (DXA) scans of the spine and proximal femur agreed to a dental examination. No association was established between the presence of severe periodontal disease and osteoporosis. INTRODUCTION: The purpose of this study is to determine whether patients with osteoporosis have an increased severity and extent of periodontal disease, taking full account of confounding factors. METHODS: Volunteer dentate women (45-65 years), who had undergone recent DXA of the femur and lumbar spine, received a clinical examination of their periodontal tissues by a single trained operator who was blind to the subject's osteoporosis status. Clinical examinations were performed within 6 months of the DXA. Basic Periodontal Examination score, gingival bleeding score, periodontal pocket depth, recession and calculus were the periodontal outcome measures. Potential confounding factors were recorded. Logistic regression was performed for the dichotomous outcome measure of severe periodontal disease (present or absent) with osteoporotic status, adjusting for confounding factors. RESULTS: There were 380 dentate participants for whom DXA data were available. Of these, 98 had osteoporosis. When compared with osteoporotic subjects, those with normal bone mineral density were significantly younger (p = 0.01), had a higher body mass index (p = 0.03) and had more teeth (p = 0.01). The prevalence of severe periodontal disease in the sample was 39 %. The unadjusted odds ratio for the association between osteoporosis and severe periodontal disease was 1.21 (0.76 to 1.93). The adjusted odds ratio analysis including other covariates (age, smoking, hormone replacement therapy, alcohol) was 0.99 (0.61 to 1.61). CONCLUSION: No association was established between the presence of severe periodontal disease and osteoporosis.

Object position and image magnification in dental panoramic radiography: a theoretical analysis.

OBJECTIVES: The purpose of our study was to investigate how image magnification and distortion in dental panoramic radiography are influenced by object size and position for a small round object such as a ball bearing used for calibration. METHODS: Two ball bearings (2.5 mm and 6 mm in diameter) were placed at approximately the same position between the teeth of a plastic skull and radiographed 21 times. The skull was replaced each time. Their images were measured by software using edge detection and ellipse-fitting algorithms. Using a standard definition of magnification, equations were derived to enable an object's magnification to be determined from its position and vice versa knowing the diameter and machine parameters. RESULTS: The average magnification of the 2.5 mm ball bearing was 1.292 (0.0445) horizontally and 1.257 (0.0067) vertically with a mean ratio of 1.028 (0.0322); standard deviations are in parentheses. The figures for the 6 mm ball bearing were 1.286 (0.0068), 1.255 (0.0018) and 1.025 (0.0061), respectively. Derived positions of each ball bearing from magnification were more consistent horizontally than vertically. There was less variation in either direction for the 6 mm ball bearing than the 2.5 mm one. CONCLUSIONS: Automatic measurement of image size resulted in less variation in vertical magnification values than horizontal. There are only certain positions in the focal trough that achieve zero distortion. Object location can be determined from its diameter, measured magnification and machine parameters. The 6 mm diameter ball bearing is preferable to the 2.5 mm one for more reliable magnification measurement and position determination.

Rampant host- and defensive phenotype-associated diversification in a goldenrod gall midge.

Natural selection can play an important role in the genetic divergence of populations and their subsequent speciation. Such adaptive diversification, or ecological speciation, might underlie the enormous diversity of plant-feeding insects that frequently experience strong selection pressures associated with host plant use as well as from natural enemies. This view is supported by increasing documentation of host-associated (genetic) differentiation in populations of plant-feeding insects using alternate hosts. Here, we examine evolutionary diversification in a single nominal taxon, the gall midge Asteromyia carbonifera (O.S.), with respect to host plant use and gall phenotype. Because galls can be viewed as extended defensive phenotypes of the midges, gall morphology is likely to be a reflection of selective pressures by enemies. Using phylogenetic and comparative analyses of mtDNA and nuclear sequence data, we find evidence that A. carbonifera populations are rapidly diversifying along host plant and gall morphological lines. At a broad scale, geography explains surprisingly little genetic variation, and there is little evidence of strict co-cladogenesis with their Solidago hosts. Gall morphology is relatively labile, distinct gall morphs have evolved repeatedly and colonized multiple hosts, and multiple genetically and morphologically distinct morphs frequently coexist on a single host plant species. These results suggest that Asteromyia carbonifera is in the midst of an adaptive radiation driven by multitrophic selective pressures. Similar complex community pressures are likely to play a role in the diversification of other herbivorous insect groups.

Students' perception of the prognosis for a single-surface amalgam restoration.

The aim of the study was to assess the self-rated skill, clinical judgement and competency of final-year pre-doctoral dental students. The study was also designed to determine whether the students' estimated durability of their single-surface restorations was determined by their confidence. Students were given a questionnaire and completed it anonymously. One hundred and ninety-six forms were returned from the 238 students (82% return rate). Complete analysis was possible on 169 questionnaires. The students' self-assessed skill and judgement were a significant factor in predicting how long they would tell a patient that their restoration would last. Those ranking themselves below average were more likely to state that their amalgam restorations would have a shorter life (odds increased by 2.82 for those ranking themselves lower than most others). There was a significant association between the students' self-assessed skill and judgement and their confidence in dealing with both the initial management of patients' medical emergencies (ρ = 0.244, P = 0.001, n = 191) and their general confidence in dealing with medical emergencies (ρ = 0.187, P = 0.01, n = 188). Given a conversational scenario with a patient, the treatment prognosis given by final-year pre-doctoral students for a single-surface amalgam restoration was dependent on their self-assessed competence, skill and judgement.

The relationship between osteoporosis and periodontitis in women aged 45-70 years.

OBJECTIVE: To explore the possible relationship between the osteoporotic condition and the severity of periodontitis in women aged 45-70 years. MATERIALS AND METHODS: Ninety women with generalized chronic periodontitis, aged 45-70 years, were studied. Areal bone mineral density (BMDa) was assessed using standardized dual energy X-ray absorptiometry (normal: T-score ≥ -1, osteopenic: -2.5 ≤ T-score <-1, osteoporotic: T-score < -2.5). Gingival index (GI), bleeding on probing, clinical attachment loss (CAL), probing pocket depth and gingival recession (GR) were recorded. Periodontitis severity was represented by CAL. Menopausal condition and smoking were documented. RESULTS: Mean GI, bleeding on probing, CAL and GR were significantly greater for osteoporotic women than women with normal BMDa (P = 0.002, P = 0.01, P = 0.04, respectively). Osteopenic women and women with normal BMDa significantly differed in mean GI (P = 0.02). The associations found between osteoporotic women and women with normal BMDa and the associations found between osteopenic women and women with normal BMDa existed even after adjusting for smoking and menopausal status. CONCLUSION: Subjects with osteoporosis (OPR) presented with greater CAL than the subjects with normal BMDa, which suggests a greater severity of periodontitis. Subjects with OPR had greater GR than the subjects with normal BMDa. Subjects with osteopenia and subjects with normal BMDa did not differ in CAL, which might suggest that the early diagnosis of reduced BMDa, prior to the establishment of a significant negative impact on the periodontal tissues, might be important. Smoking and menopausal status did not alter these associations.

The osteoinductive effect of chitosan-collagen composites around pure titanium implant surfaces in rats.

BACKGROUND AND OBJECTIVE: The enhancing effects of chitosan on activation of platelets and differentiation of osteoprogenitor cells have been demonstrated in vitro. The purpose of this study was to evaluate the in vivo osteoinductive effect of chitosan-collagen composites around pure titanium implant surfaces. MATERIAL AND METHODS: Chitosan-collagen composites containing chitosan of different molecular weights (450 and 750 kDa) were wrapped onto titanium implants and embedded into the subcutaneous area on the back of 15 Sprague-Dawley rats. The control consisted of implants wrapped with plain collagen type I membranes. Implants and surrounding tissues were retrieved 6 wks after surgery and identified by Alizarin red and Alcian blue whole mount staining. The newly formed structures in the test groups were further analyzed by Toluidine blue and Masson-Goldner trichrome staining, and immunohistochemical staining with osteopontin and alkaline phosphotase. The bone formation parameters of the new bone in the two test groups were measured and compared. RESULTS: New bone formed ectopically in both chitosan-collagen groups, whereas no bone induction occurred in the negative control group. These newly formed bone-like structures were further confirmed by immunohistochemical staining. Comparison of bone parameters of the newly induced bone revealed no statistically significant differences between the 450 and 750 kDa chitosan-collagen groups. CONCLUSION: Our results demonstrated that chitosan-collagen composites might induce in vivo new bone formation around pure titanium implant surfaces. Different molecular weights of chitosan did not show significantly different effects on the osteoinductive potential of the test materials.

Changes in mandibular cortical width measurements with age in men and women.

UNLABELLED: Automated software was used to measure the mandibular cortical width in a large sample of dental radiographs. We determined that cortical thinning normally starts in women at age 42.5 years and accelerates thereafter. We can estimate population referral rates and thus enable cost benefit analyses for osteoporosis detection by dentists. INTRODUCTION: Previous studies have shown that the mandibular cortical width is significantly correlated with the bone mineral density at sites which may undergo osteoporotic fracture, e.g. hip. Mandibular cortical width can be determined automatically from dental panoramic radiographs that dentists frequently request, using appropriate software. We study the distribution of cortical width given age to predict those patients requiring further investigation for osteoporosis. METHODS: The mandibular cortical width was measured in 4,949 dental panoramic tomograms, in patients aged 15-94 years. The inferior and superior cortical edges were detected automatically using a global active shape model image search, followed by an active appearance model search. Nonparametric statistical analysis and nonlinear piecewise linear/quadratic regression were used to analyse the data. RESULTS: For females, the mean cortical width had a linear increase before the age of 17 years, a period of no change (estimate = 3.25 mm, se = 0.01) until the age of 42.5 years, followed by a quadratic decrease with age. For males, it had a linear increase before the age of 19 years, a constant value (estimate = 0.37 mm, se = 0.01) until the age of 36 years and then a slow linear decrease. The rate of decrease in mean cortical width goes from 0.049 to 0.105 standard deviations per year in the 60-80-year-old female age group, in line with published bone mineral density T-score reductions. CONCLUSIONS: The pattern of decrease in mandibular cortical width with age was similar to the known pattern of bone loss from the hip, accelerating in women after the age of 42.5 years.

Designing cobalt chromium removable partial dentures for patients with shortened dental arches: a pilot survey.

The aim of this survey was to investigate the quality of prescription for the fabrication of cobalt chromium removable partial dentures (RPDs) that are used to extend the shortened dental arches (SDAs). A survey of four commercial dental laboratories located in northern England was conducted. The target of this survey was cobalt chromium RPDs that were requested to restore SDAs comprising the anterior teeth and 2-4 premolars. Dentists' prescriptions were scrutinised, and a special data collection form was completed accordingly. A total of 94 dentists' prescriptions and associated SDA casts were examined. Almost all the requested cobalt chromium RPDs were clasp-retained RPDs (97%). Scrutinising the 91 prescriptions for clasp-retained cobalt chromium RPDs showed that dentists' prescriptions did not have any instructions about the design of the partial denture in a considerable proportion of the cases (32%). Teeth to be clasped were identified clearly in 45% of the prescriptions. A majority of the dentists (64%) failed to provide any instructions about the design of the rests to be placed on the most posterior premolar abutment teeth. A considerable proportion of the dentists delegated the task of selecting the type of the major connector to the dental technician (41%). Only 21 (23%) of the examined casts had clearly defined rest seat preparation. The outcome of this pilot survey shows inadequate quality of prescription in designing RPDs for patients with SDAs. This finding has an ethical and clinical bearing and does not fit with current legal guidelines relevant to designing RPDs.

Healing of tooth extraction sockets in the streptozotocin diabetic rat model: Induction of cartilage by BMP-6.

Cartilage does not form in the tooth extraction socket of the normal rat. The aim of the study was to determine if adding BMP-6 to the extraction socket would cause chondrogenic differentiation in the diabetic rat. A group of 8-week-old rats were injected intraperitoneally with a diabetogenic agent, streptozotocin, and a control group received citrate buffer only. Three weeks later, the maxillary molar teeth were extracted and either BMP-6 or saline applied to the extraction sockets. Rats from each group were killed on days 3, 5, 7, and 9 after tooth extraction. In the diabetic rats treated with BMP-6, there was a cellular subperiosteal reaction at day 3 in the extra-alveolar tissues, which by day 7 had formed a large mass of cartilage. Cartilage was induced in the subperiosteal region of the socket extra-alveolar bone following the application of BMP-6 in the diabetic rat.

Glaucoma surgery: trainee outcomes and implications for future training: southeast Scotland.

AIM: Postoperative outcome of trainee glaucoma surgery compared with glaucoma specialist consultant surgery. Survey of Scottish consultant ophthalmologists' views on trainee surgery. METHOD: Retrospective analysis of 128 trainee and 176 consultant trabeculectomies, with minimum postoperative follow-up of 2 years. Prospective postal survey of 80 Scottish consultant ophthalmologists. RESULTS: Trainees operated mainly on cases of chronic open angle glaucoma, while consultants operated on significantly more complicated glaucomas (P=0.0004). Trainee cases had more bleb leaks (P=0.01), hypotony (P=0.05), early (P=0.01) and late (P=0.03) return to theatre, and bleb interventions (P=0.01). Trainee mitomycin trabeculectomies were associated with higher rates of return to theatre (P=0.002), and cataract extraction within the first postoperative year (P=0.002). Trainee cases of pseudoexfoliation had more early complications (P=0.024), and trainee cases of low tension required more bleb interventions (P=0.05). There was no significant difference (P>0.05) between average intra-ocular pressure control (IOP) at postoperative visit year 1 between consultant (14.3 mm Hg) and trainee (13.9 mm Hg) cases. More than 50% of the 80 Scottish ophthalmology consultants surveyed, indicated that glaucoma surgery training requirements should be retained. CONCLUSIONS: Trainee trabeculectomy cases showed significantly higher rates of early complications, return to theatres, and bleb interventions compared with consultant cases. Satisfactory IOP control was achieved in both groups at postoperative year 1. Trainee cases require careful preoperative selection, avoiding complicated glaucomas including pseudoexfoliation and low tension, and those that require mitomycin. The majority of Scottish consultants wish to retain glaucoma surgery within the remit of generic training.

Nasopharyngeal carcinoma metastatic to the mandible.

Nasopharyngeal carcinoma (NPC) is one of the most common malignancies in the head and neck region, especially among those of Chinese origin. NPC has multifactorial aetiologies including genetic susceptibility, consumption of food with high salt content, and the Epstein-Barr virus. The primary tumour usually arises from the lateral walls of the nasopharynx and is characterized by a rich sub-mucosal lymphatic structure, often leading to cervical lymph node metastasis. Distant metastasis has been recognized to be a major cause of treatment failure in patients with nasopharyngeal carcinoma. Bone, liver and lung are the most frequent sites of NPC metastases.