Clinical performance of resin composite restorations placed by dental students

Aim: A retrospective, cross-sectional study was carried out to evaluate the performance of resin composite restorations placed by undergraduate dental students with 1 to 15 years of placement based on dental records. Methods: Four calibrated operators evaluated 498 restorations (anterior and posterior) of 120 patients according to Ryge’s validated criteria (USPHS). Results: The criteria that showed the smallest changes between the types of failures were color matching, marginal discoloration and surface texture. Regarding the longevity, the surface texture showed an increase in the frequency of failures from the second time interval (3.1 to 6 years). Higher prevalence of failure was found in class II and III restorations, with secondary caries being the main reason. No significant differences were found for anatomic form, marginal adaptation, and color matching. Class V restorations showed a higher fracture rate with total displacement of the restoration, with no increase in the frequency of fracture over time. Conclusion: High rate of restoration failure was observed, possibly due to the lack of experience and skills of the students. This outcome highlight the need for continuous revision and improvements of teaching practice regarding the development of clinical competences and skills by dental students.

Simulation of tectonic stress field and prediction of fracture distribution in shale reservoir

In this paper, a finite element-based fracture prediction method for shale reservoirs was proposed using geostress field simulations, uniaxial and triaxial compression deformation tests, and acoustic emission geostress tests. Given the characteristics of tensile and shear fractures mainly developed in organic-rich shales, Griffith and Coulomb – Mohr criteria were used to calculate shale reservoirs' tensile and shear fracture rates. Furthermore, the total fracture rate of shale reservoirs was calculated based on the ratio of tension and shear fractures to the total number of fractures. This method has been effectively applied in predicting fracture distribution in the Lower Silurian Longmaxi Formation shale reservoir in southeastern Chongqing, China. This method provides a new way for shale gas sweet spot optimization. The simulation results have a significant reference value for the design of shale gas horizontal wells and fracturing reconstruction programs.

Characteristics of Overburden Failure and Fracture Evolution in Shallow Buried Working Face with Large Mining Height

In order to solve the issues of uncertain overburden failure height and water loss at the Daliuta coal mine, the collapse characteristics of overburden and the development height of water-conducting fractured zone were studied by using physical modeling, FLAC 3D numerical simulation, and field observation, which were used to verify each other. In order to quantitatively analyze the distribution characteristics of fracture rate of overlying rock mass in goaf, the overburden collapse image was binarized. The results showed that: (1) the failure characteristics of overburden in goaf obtained by the three research methods were roughly consistent, and the reliability of the results was high. The overburden failure height of No. 5−2 coal with large mining height was 137.32–153 m, which was 20.8–23.2 times the mining height. (2) The repeated mining of No. 5−2 coal intensified the further failure of the disturbed rock mass in the No. 2−2 coal goaf. (3) In the horizontal direction of the goaf, the fracture rate of rock mass was distributed in the shape of “saddle”. In the longitudinal direction of the goaf, the rock mass fracture rate decreased in a logarithmic function with the increase of the height from the mining coal seam. Overall, the conclusions are of engineering significance for accurately adopting water resources protection mining technology and reducing mine water inrush disasters.

Fracture Incidence of Kedo-S Square Pediatric Rotary Files: A Prospective Clinical Study

Objective The primary focus of this clinical study was to analyze the probability of occurrence of instrument fracture after root canal preparation of primary molars with the help of Kedo-S Square pediatric rotary file. Materials and Methods Three experienced specialists treated 100 primary maxillary and mandibular molars (335 root canals) using a standardized protocol over 2 months. Biomechanical preparations were carried out using Kedo-S Square file, as per the suggestions given by the manufacturer. Every instrument in Group A helped handle three clinical cases, while for groups B, C and D, they helped in handling 5, 9, and 12 cases, respectively. Making use of an operational microscope, the rotary files, after being pulled out from the canal, were observed. The values were tabulated, and descriptive statistics were performed. Results There were two fractures (2%), of which 1 occurred in group C in the apical 1/3rd of distobuccal canal of maxillary molar, and the other occurred in group D in the apical 1/3rd of mesiobuccal canal of maxillary molar. Conclusions The fracture rate of Kedo-S Square rotary file is quite low. It is primarily in the buccal canals of the maxillary molars and the apical third of the root canal that the instrument has a greater probability of separation.

Comparison of Clinical Outcomes of Flexible Intramedullary Nailing (FIN) with External Fixation in Pediatric Open Tibial Fractures

Objective: To compare the clinical outcome of flexible intramedullary nailing (FIN) with external fixator in pediatric open tibial fractures. Subjects and Methods: In this randomized comparative study, 80 children having age 5 year to 14 years who presented with open tibial fractures were included. The study was conducted from June-2020 to June-2021 in Islam Hospital Sialkot and Allama Iqbal Memorial Hospital Sialkot. Patients were divided into two equal groups. Group A: underwent external fixation and group B: underwent flexible intramedullary nailing for the surgical management of tibial fractures. Frequency of infections surrounding pins, painful bursitis and re fracture rate within 3 months after surgery was recorded. Results: The mean age of children was 8.42±3.82 years in external fixator group versus 8.40±4.0 years in FIN group (p-value 0.97). Infection-surrounding pins occurred in 9 (22.5%) children were belonging to external fixator group and 01 (2.5%) children was belonging to FIN group (p-value 0.007). Refracture occurred in 6 (15.0%) patients in external fixator group and in no (0.0%) children in FIN group (p-value 0.01). Painful bursitis occurred 2 (5.0%) patient was in external fixator group and in 13 (32.5%) in FIN group (p-value 0.002). Conclusion: Clinical outcome is better in patients treated with FIN as compared to the external fixator for the treatment of pediatric open tibial shaft fractures. Keywords: Flexible intramedullary nails, External fixator, Tibial fractures.

Comparative efficacy and safety of alendronate and teriparatide in bone loss reduction and prevention of vertebral fracture in osteoporotic Chinese patients

Purpose: To compare the effect of teriparatide and alendronate (bisphosphonate, BPP) among Chinese patients with osteoporosis (OoP).Method: Chinese subjects aged > 40 years with a history of vertebral/non-vertebral osteoporotic fragility/fractures were enrolled, and administered either teriparatide (TPT 20 μg/day) subcutaneously or alendronate (BPP)10 mg orally once daily for 12 months. Bone mineral density (BMD), measured using x-ray techniques, and bone formation biomarkers such as osteocalcin [OTC] and bone alkaline phosphatase, were assessed at baseline, and after 6 and 12 months of treatment. The proportion of patients with fractures as well as fracture rate were also recorded. The safety of the drugs was evaluated based treatment emergent adverse events.Result: In Chinese men with OoP, substantially greater improvement in BMD was observed in TPT group, compared to BPP group. TPT demonstrated substantially greater improvement in OTC and, bone alkaline phosphatase than in BPP. Also, patients treated with TPT had significantly lower incidence of new fracture than BPP group during the study period, irrespective of gender distribution (relative risk reduction at 6 and 12 months was 45 and 47 % respectively). The results showed that TPT was superior to BPP in increasing BMD and bone formation biomarkers and reducing new fractures in both male and female patients with osteoporosis.Conclusion: Teriparatide is effective and safe in reducing bone loss and preventing vertebral fractures in Chinese patients with osteoporosis. Furthermore, the results show that there is no gender difference in the efficacy and safety of teriparatide in osteoporosis.

Ten-year survival of ceramic-on-ceramic total hip arthroplasty in patients younger than 60 years: a systematic review and meta-analysis

Background Total hip arthroplasty (THA) with ceramic-on-ceramic (CoC) was created to minimise wear debris and aseptic loosening. A decade ago, a meta-analysis showed a 10-year survival rate of just 89%. Based on the excellent tribology of the current CoC, significant improvement of implant survivorship is expected. In patients younger than 60, we conducted a meta-analysis to assess 10-year survival and complications after using current primary CoC THA. Materials and methods PubMed, Scopus, EMBASE, Virtual Health Library, and Cochrane Library were used to scan for published trials that met the inclusion criteria until January 2019. The qualified studies were subjected to a systematic review and proportional analysis, and the randomised controlled trials (RCTs) were included in a comparison meta-analysis. Results Thirteen studies were included 156 findings. The total number of hips was 2278. Nine studies were cohort, and four were RCTs between ceramic and polyethylene cups. The analysis revealed an average age of 44 years (range 24–54). The 10-year survival 96% (95% CI; 95.4–96.8%), aseptic loosening rate 0.516. (95% CI; 0.265–0.903), ceramic fracture rate 0.620 (95% CI; 0.34–1.034) and squeaking rate 2.687 (95% CI; 1.279–4.593). A comparison meta-analysis revealed the risk ratio (RR) for revision was 0.27 (95% CI; 0.15–0.47), and for aseptic loosening 0.15 (0.03–0.70) favouring CoC, while RR for component fracture was 1.62 (95% CI; 0.27–9.66) favouring the polyethylene. Conclusion In patients under sixty, current CoC THAs are correlated with better 10-year outcomes than before and have high survivorship rates. Level of evidence: Level I.

Influence of Hyponatremia on Spinal Bone Quality and Fractures Due to Low-Energy Trauma

Background and Objectives: Hyponatremia is the most common electrolyte disorder in elderly and associated with increased risk of falls. Clinical studies as well as small animal experiments suggested an association between chronic hyponatremia and osteoporosis. Furthermore, it has been assumed that subtle hyponatremia may be an independent fracture risk in the elderly. Therefore, this study was designed to evaluate the possible influence of chronic hyponatremia on osteoporosis and low-energy fractures of the spine. Materials and Methods: 144 patients with a vertebral body fracture (mean age: 69.15 ± 16.08; 73 females and 71 males) due to low-energy trauma were treated in a level one trauma center within one year and were included in the study. Chronic hyponatremia was defined as serum sodium < 135 mmol/L at admission. Bone mineral density (BMD) of the spine was measured using quantitative computed tomography in each patient. Results: Overall, 19.44% (n = 28) of patients in the low-energy trauma group had hyponatremia. In the group with fractures caused by low-energy trauma, the proportion of hyponatremia of patients older than 65 years was significantly increased as compared to younger patients (p** = 0.0016). Furthermore, there was no significant gender difference in the hyponatremia group. Of 28 patients with chronic hyponatremia, all patients had decreased bone quality. Four patients showed osteopenia and the other 24 patients even showed osteoporosis. In the low-energy trauma group, the BMD correlated significantly with serum sodium (r = 0.396; p*** < 0.001). Conclusions: The results suggest that chronic hyponatremia affects bone quality. Patients with chronic hyponatremia have an increased prevalence of fractures after low-energy trauma due to a decreased bone quality. Therefore, physicians from different specialties should focus on the treatment of chronic hyponatremia to reduce the fracture rate after low-energy trauma, particularly with elderly patients.

Clinical Longevity of Indirect Composite Resin Inlays and Onlays: An Up to 9-Year Prospective Study

Objective This clinical study evaluated the clinical performance of composite resin inlays and onlays over 9 years. Materials and Methods Sixty composite resin inlays and onlays were placed in 32 patients, aged 20 to 60 years, by a single operator using the same clinical procedure. The restorations were examined for fracture rate; esthetics; and patient acceptance and marginal integrity, including caries, marginal discoloration, tooth integrity, and surface texture. All restorations were evaluated at the time of placement and 3, 6, and 9 years after placement by using the modified U.S. Public Health Service criteria. Results At the 3-year follow-up, an Alpha score was given to 88.4% of restorations, while a Bravo score was given to the remaining 11.6%. There was not any failure. At the 6-year follow-up, the success rate of the restorations was 100% without failure. None of the restorations was scored with Delta (D). An Alpha score was given to 60% of the restorations, a Bravo score was assigned to 35%, and a Charlie score was 5% of the restorations. Overall, the success rate of the restorations at 9-year follow-up was 85% and the failure rate was 15%. An Alpha score was given to 15% of the restorations, a Bravo score was given to 50%, a Charlie score was assigned to 20%, and a D score was given to 15% of the restorations. Conclusion Indirect resin composite inlays and onlays showed acceptable long-term clinical results. The success rate of the restorations at 9-year follow-up was 85% and the failure rate was 15%.