Toughness Measurement in Direct Resin Composites Using Quantitative Fractographic Analysis
Brendan M. Angus, John J. Mecholsky Jr., Nader Abdulhameed (abstract)Objective: To outline a procedure to determine the fracture toughness of direct resin composites failing from “natural” flaws. Methodology: Tensile (hour glass) tests (n = 30) of a conventional hybrid dental composite (Tetric EvoCeram, Ivoclar Vivadent) were fabricated and fractured in uniaxial tension loaded at a crosshead speed of 1 mm/min (≥ 10 MPa/s). The fracture toughness of the material was then calculated using the stress at failure and measurement of the crack size from fractographic analysis using SEM. Hardness (H) measurements were taken using a Vickers pyramidal diamond indenter. Elastic modulus (E) was calculated from the E/H ratio using a Knoop indenter. Results: The values for fracture toughness found were similar to other Bis-GMA based dental composites 0.5 ±0.2 MPa. The Vickers Hardness was 509 ± 27 MPa and the Knoop Hardness was 495 ± 14 MPa using 0.5 kg/30 s, while the elastic modulus was 9.5 ±1.4 GPa. Conclusion: The differences found in fracture toughness between this study and previous published studies are most likely due to variation in technique and material. Quantitative fractographic analysis offers a different method to evaluate the toughness of direct resin composites. Keywords: fracture toughness, resin composites, fractography, dental materials. | (read pdf) |
Association between serum resistin level and periodontal condition change among elderly people
Hiroshi Ogawa, Teerasak Damrongrungruang, Reiko Furugen, Hideaki Hayashida, Toshiyuki Saito, Akihiro Yoshihara1f, Hideo Miyazaki (abstract)Aim: This study aimed to compare periodontal condition in four years of Japanese elderly between high and low serum resistin levels. Materials and methods: One hundred and thirty-two dentate community-dwelling participants enrolled in this cohort study. At baseline, blood sample were drawn for serum resistin and other adipokines/cytokines measurements. The participants were then divided into 2 groups; low resistin (LR, resistin < 5.3 ng/mL) group (n = 84) and high resistin (HR, resistin ≥ 5.3 ng/mL) group (n = 48). At baseline and after four years, all participants were subjected to periodontal examination (assessment pocket depth; PD and bleeding on probing; BOP). Annual general/oral health questionnaires were also performed. Intergroup comparisons of periodontal parameters and categorical variables were accomplished by t-test and Chi-square test, respectively. Association between baseline serum resistin level and periodontal condition alteration after four years in each group were analyzed by a multiple linear regression analysis. Results: At baseline, HR group had more sites with PD ≥ 4 mm concomitant BOP than those of LR group (5.8±9.0 vs. 2.8±4.8 sites). High serum resistin concentration and number of tooth loss markedly associated with reduction of sites with PD ≥ 4 mm and PD ≥ 4 mm concomitant BOP. Conclusion: High serum resistin level might negatively be associated to periodontal disease progression. Keywords: adipokine, elderly, inflammation, periodontitis, resistin. | (read pdf) |
Manifestation of sleep bruxism according to the age of patients
Dumitru Romaniuc,Valeriu Fala, Victor Lacusta, Gheorghe Bordeniuc, Paula Fala (abstract)Introduction: Bruxism is a widespread condition, affecting up to 85-90% of the general population, and in 5% of these individuals, the grinding evolves into a clinical condition. In many cases, sleep bruxism is latent, the disorder may be identified by its consequences (dental wear, etc.). This ascertains the need to develop diagnostic methods that may be able to identify bruxism at the initial stages of the disorder. Aim of the study: to determine the peculiarities of the clinical manifestation of primary sleep bruxism (SB) based on the age of the patients. Methodology: One hundred patients with primary SB (70 patients aged between 18-35 and 30 patients aged between 35-50) were investigated. The clinical features of SB (algic syndrome, myogenic disorders, temporomandibular disorders, dental wear, psychoemotional disorders, sleep quality alterations) were also investigated. Results: The expression of emotional stress in patients of various ages was almost identical. The highest clenching frequency and duration, as well as a higher clinical expression of sleep bruxism was observed in patients under 35. The components of the algic syndrome show a varied expression for different age groups – patients under 35 had more severe disorders of the nocturnal episodes and myogenic-spastic events; older patients (35-50) were characterized by a prevalence of local and diffuse myogenic structural disorders, arthrogenic pain and severe sleep disturbances. Conclusion: Electromyography and ultrasonography can reveal important morpho-functional peculiarities of the masticatory muscles that are associated with the severity of SB in patients from different age groups. Keywords: bruxism, electromyography, ultrasonography, temporomandibular disorders, diagnostics. | (read pdf) |
Are dental measurements taken on plaster casts comparable to those taken from CBCT images and laser scanned surfaces?
Luca Pisoni, Marina Codari, Simone Galli, Francesca M.E. Rusconi, Gianluca Martino Tartaglia, Valentina Pucciarelli, Chiarella Sforza (abstract)Introduction: Intraoral scanning techniques, laser scans and cone-beam computed tomography (CBCT) are becoming widely diffused in dental practice. These instruments can replace dental plaster casts with digital models; recent investigations have found that measurements taken on digital models do not differ clinically from those obtained on CBCT scans and physical models, but only intra-examiner reliability has been assessed. In the current study we tested both intra- and inter-examiner variations, together with inter-techniques reliability. Methodology: Data from six adult subjects were retrospectively obtained. Twelve dental distances were measured on dental plaster casts using a digital calliper; on digital 3D CBCT images using inVivoDental software (Anatomage, San Jose, CA); and on laser scanned surfaces using Mirror Vectra Software (Canfield Scientific, Fairfield, NJ). Two different operators performed all measurements twice. Bland-Altman analysis, Kruskal-Wallis and Wilcoxon tests were used for comparisons. Results: The intra- and inter-operator biases range was 0-0.34 mm. The reproducibility range was 72-99%. The three different techniques gave very similar measurements, with biases between ±0.1 mm. Reproducibility ranged between 90 and 100%; the best reproducibility coefficients were found between plaster and digital casts, and only three differences were larger than 0.5 mm. Calliper measurements slightly overestimated digital casts values. Only the mesiodistal distance of tooth 24 (p=0.002) was significantly different among techniques. Conclusion: Measurements on digital dental models and CBCT reconstructions of the dental arches seem clinically reliable as direct calliper measurements. The inter- and intra-operator reliabilities were acceptable, some more care may be needed for CBCT measurements. Keywords: teeth, laser scan, cone beam computerised tomography. | (read pdf) |
Bloodloss and transfusion need in orthognathic surgery: review of literature
Constantinus Politis, Jimoh Olubanwo Agbaje, Ivo Lambrichts (abstract)Background: Blood loss during orthognathic surgery has gained renewed interest due to the omission of surgical final splints in bimaxillary surgery, which increased operative time, while orthognathic surgery is increasingly indicated for the treatment of the obstructive sleep apnea syndrome (OSAS). OSAS subjects are usually older with more medical comorbidity which requires blood transfusion. Objective: To review (reported) blood loss and transfusion practice in orthognathic surgery in the literature published between 1976 and 2012 and to compare these data with more recent developments. The relationship between the duration of the surgery and the related blood loss and/or transfusion was examined. Data Sources: The 1976-2012 orthognathic literature was searched to determine the relationship between the duration of the surgery and the related blood loss and/or transfusion. Study Selection: Articles containing clear information on the operation time, blood loss, transfusion, and orthognathic surgery were included. Data Extraction: Information on the operation time, blood loss, transfusion, and orthognathic surgery was extracted. Data Synthesis: Different descriptions of procedures and techniques are grouped together in a concise and coherent way, resulting in a number of categories per label. Using this grouping various targeted questions are exploited and answered. Keywords: orthognathic surgery, blood loss, operation time, blood transfusion. | (read pdf) |
Non syndromic familial hypodontia – a case series
Halah Binladen, Amal Mahmoud, Neeta Chandwani, Manal El-Halabi (abstract)Aim: The aim of this case report is to discuss the features of non-syndromic familial hypodontia, which was noted in three siblings who had an unremarkable medical history. Summary: Congenital absence of teeth is a common dental anomaly referring to teeth that fail to erupt in the oral cavity and remain invisible in radiographs. Congenital tooth agenesis is defined by the number of missing teeth, excluding the third molars; hypodontia refers to the absence of less than six teeth, while oligodontia is the absence of six or more teeth. Tooth agenesis can occur as part of a genetic syndrome such as the cleft lip and palate, ectodermal dysplasia and Trisomy 21 (syndromic hypodontia) or an isolated trait (nonsyndromic hypodontia). Non-syndromic hypodontia is the most common form and can be familial or sporadic. The most supported etiological theory suggests that tooth agenesis may be due to a combination of genetic and environmental factors, which lead to disturbances in the tooth germ during the initial formation stages.
This case series reports bilateral agenesis of the maxillary canines in siblings, which is quite rare in occurrence. The management of these anomalies involves a multidisciplinary approach in order to restore esthetics and function. An early diagnosis can lead to effective treatment planning and satisfactory results. Key learning points: The clinical manifestations as well as the short and long term management of this condition are discussed. Keywords: hypodontia, congenital, nonsyndromic, management. | (read pdf) |
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