Evaluation of flexural strength of composite by addition of dental amalgam powder: a pilot study

Dental composites are showing versatility in the field of restorative dentistry. Strength is main issue for their use especially in stress bearing area. Present study was aimed to evaluate the flexural strength of dental amalgam incorporated nano filled hybrid composite. Mechanical incorporation of a commercially available dental amalgam powder in nano filled hybrid composite was performed through amalgamator. Specimens were prepared and analyzed according to ISO standard No. 4049. Specimens analyzed were six [n=3] for each group. Null hypothesis for the study was no difference in the flexural strength of a commercially available dental composite and the prepared one which was rejected by the test statistics. Flexural strength of the control material was 90 Mpa while for the test material was 106.12 Mpa. Results showed a marked difference in the values of flexural strength of both the materials. Flexural strength can be increased by incorporating dental amalgam powder. Dental amalgam powder is a potential candidate for a high flexural strength and antibacterial composite. The study needs more trials on different aspects and evaluation of mechanical properties

Knowledge of dentists about epilepsy and their attitude toward the dental treatment of epileptic patients: a survey of dentists in Peshawar - Pakistan

The relationship of epilepsy with society, knowledge of people, attitude, and how may it affect the access of people with epilepsy to dental care. A questionnaire that explored facts about the knowledge, attitude and willingness to provide dental care to people with epilepsy was delivered to 129 dentists personally in the city of Peshawar [KPK], Pakistan. Of the 129 respondents, 10.9% were general dentists. Knowledge was patchy about the epidemiology, causes, treatment and recognition of epilepsy. 44% of dentists did not think that they could safely treat patient of epilepsy in their offices. Lack of knowledge and negative attitude towards epilepsy may affect the access to dental care for people with epilepsy

Dimensional stability of vinylsiloxanether impression material after autoclave sterilization - an in vitro study

Dental impressions are often neglected in clinical practice as a source of spread of infectious diseases. In Pakistan more than fifty percent of the clinicians do not disinfect impressions. Blood and saliva contaminated impressions should be either disinfected or sterilized before further handling. Aim of this study was to determine effect of autoclave sterilization on the time dependent dimensional stability of vinylsiloxanether impression material. Impressions of stainless steel die [ADA/ANSI specification No. 19], were made of Vinylsiloxanether. Out of 40 specimens, half were allotted to group A and were autoclaved at 134°C AND 20 psi for 5 minutes. Rest of the specimens [Group B] served as a control. Dimensional changes were calculated for two time intervals i.e. after one hour and after twenty-four hours. Samples were scanned and images were analyzed by using Adobe reader XI [AcroRd 32] software. Paired t-test showed significant difference [p = 0.007] between readings at first hour [-0.047%] and twenty fourth hour [0.084%] in group A. Whereas independent t-test showed no significant difference in group A and B for both time intervals i.e. at first hour [p = 0.162] and twenty fourth hour [p = 0.148]. It was concluded that Vinylsiloxanether can be sterilized in an autoclave without any deleterious change in dimensions

Missing teeth among school going children in a Peshawar sample

Congenitally missing teeth is the most common craniofacial malformation. It is present either individually or associated with syndrome. Hypodontia occur as a result of multifactorial trait, influenced by a combination of gene function, environmental interaction, hence vary among different ethnic regions. This study aims to determine the prevalence of missing teeth among the school going children in Peshawar, its occurrence rate among male and female and distribution of missing teeth in upper and lower jaw. This was a cross sectional study conducted with 780 school going children from age ranged 13 to 15 years. The data were recorded on a structured check list, analyzed by using SPSS version 15 and Micro Soft Excel. Out of total only 30 students were diagnosed as having missing teeth and accounted for 3.8% prevalence [3.0% in female, and 1.5% in male]. Left mandibular site accounted highest frequency 10[33.3%]. Mandibular 2nd premolar was the most commonly observed missing tooth among the sampled students. Hypodontia was more prevalent in females, though not significantly differ

interface of glass ionomer sealer and conditioned elephant tusk dentine: a scanning electron microscopy study

The purpose of this in vitro study was to characterize the interface of glass ionomer sealer and dentine conditioned with common endodontic irrigants through scanning electron microscope. The interface between Ketac-Cem radiopaque glass ionomer sealer and elephant tusk dentine conditioned with distilled water, citric acid and phosphoric acid was investigated. Cylinder of glass ionomer sealer was formed on the conditioned dentine surface and allowed to set for 60 minutes. The specimens were first shear tested to failure to determine their adhesive bond strength. Three debonded dentine specimens from each group were then processed for scanning electron microscopic study. The test failed surface of the strongest, intermediate and weakest bond strength specimens were examined. The specimens were cross sectioned and the interface was examined. The microscopic detail of the debonded interfaces between glass ionomer sealer and dentine was assessed in this study. Failures in all of the specimens were found to be mainly cohesive in nature

Effect of bleaching on shear bond strength of orthodontic brackets

The purpose of this in vitro study was to determine the effect of bleaching on shear bond strength of orthodontic brackets. This randomized control trial was performed over a period of 6 months in the department of orthodontics, de,Montmorency College of Dentistry, Lahore. A total of one hundred and forty extracted premolar teeth were included which were further divided into two groups. Group A was assigned as control group without bleaching and Group B as study group with bleaching. The teeth in both groups were embedded individually in acrylic placed in rubber moulds using a mounting jig so that the labial surfaces would be parallel to the applied force during the shear test. Group B was bleached with Pola office advanced tooth whitening system and were stored in a solution of 0.9% saline till they were bonded. The bonding process for both groups was then performed in a standard manner. After bonding bracket was properly positioned on its respective tooth. An occluso-gingival load was applied to the bracket producing a shear force at the bracket tooth interface using a computerized shear bonding testing machine. The results showed that there was no statistically significant difference between the shear bond strength of unbleached teeth and that of bleached teeth following a two weeks interval after bleaching

Comparison of working length in curved mesial canals of mandibular molar between pre-flared and non-flared group

The aim of this study was to compare the working length in the curved mesial canals of mandibular molars between pre-flared and non-flared groups. It was a comparative study which was carried out at Dental Department of PIMS [Pakistan Institute of Medical Sciences] Islamabad from 2003 to 2004. A total of 60 patients were divided equally into pre-flared and non-flared groups. In both groups a 15 # K file was used for the measurement of working length but in the pre-flared group the coronal portion of the canal was flared with Hedstrom files [25-55] or Gates Glidden Drills from # 02 to # 05 before inserting the # 15 K file. Then the tooth was radiographed at this moment and the distance between the tip of the file and the radiographic apex. The location of the tip was classified as a] within 1 mm of the radiographic apex b] more than 1 mm of radiographic apex c] over extended, beyond the radiographic apex. In the non-flared group 33.3% of the cases belonged to group [a], 40% to group [b] and 26.7% to group [c]. In the pre-flared group 73.3% of the cases belonged to group [a], 10% to group [b] and 16.7% to group [c]. It was concluded that when the coronal portion of the canal is constricted, then the clinicians cannot discern the accuracy of what they feel apically because quite often the file bends or stucks more coronally than apically. When the coronal portion of the curved canal is pre-flared or prepared then it greatly improves the access to apical portion of curved canal and thus to the apical constriction, which is an apical reference for correct working length determination, by removing the dentinal hindrances in the coronal portion of the curved canals. Thus pre-flaring is a highly recommended procedure, especially in curved canal for correct working length determination

shear bond strength of glass ionomer root canal sealer to elephant tusk dentine conditioned with common endodontic irrigants

The purpose of this in vitro study was to evaluate the shear bond strength of glass ionomer sealer to dentine exposed to common endodontic irrigants in both well and poorly prepared dentine surface. In the methodology four groups of elephant dentine sample were used. Each group was well cleaned and prepared with different irrigants for the effective removal of smear layer. One group was treated with distilled water with smear layer retained. All the dentine used for the experiment was cut in form of disks of about 2.4mm thickness with a hole in the centre and subjected to root canal preparation. All the prepared dentine samples were filled with Ketac-Cem sealer and metal pin was inserted. The shear bond strength of metal pin and sealer was tested using Instron universal testing machine. The observations of bond strength in the four sample groups were analysed statistically through ANOVA test. It was found statistically that shear bond strength with phosphoric acid treated samples was quite higher than the other samples

Smear layer and sealing ability of three root canal sealers

The purpose of this study was to determine the sealing ability of three individual sealers and to compare the sealing ability of these sealers in the presence and absence of smear layer. Total of sixty single rooted mandibular first premolar teeth were used. The crowns were removed at the cemento-enamel junction and roots prepared to # 35 K-file. The teeth were randomly divided into two equal groups A and B. The smear layer was removed from group B with EDTA [17%] and NaOCl [5.25%] but it was not removed in group A. Group A was then divided into three sub-groups, Al, A2 and A3. Group B was also divided into three sub-groups, Bl, B2 and B3. Each sub-group consisted of 10 specimens. In sub-groups Al andBl, AH Plus sealer, in sub-groups A2 and B2, Ketac-endo sealer and in sub-groups A3 and B3, Roth sealer was used and obturated withguttapercha using lateral condensation technique. After storage in 100% humidity at 37°C for one week, the root surfaces were coated with nail polish [except at the apex] and suspended in 2% methylene blue dye solution for one week. The roots were sectioned logitudinally to determine the following mean levels of dye penetration, Al -2.675 mm, Bl -2.092mm,A2-2.346mmB2endo-4.520mm,A3-4.929mm,B3-3.372mm.This study has illustrated that Ketac-Endo sealer provides significantly better seal in the presence of smear layer than in the absence of smear layer. Moreover it gave better seal than Roth 801 sealer in the presence of smear layer

effect of resin coating technique on shear bond strength

The purpose of this study was to investigate the shear bond strength of metal discs luted to dentine using Resin Coating Technique. In this study the adhesives used were dentine bonding agents, namely, Clearfil SE Bond and Syntac Sprint which were applied one week prior to cementation of Cobalt Chromium [Co-Cr] alloy discs to determine if there was any increase in the bond strengths when later luted using Panavia F and Variolink II. Thus there were four test groups with twelve teeth in each group i.e. Group I:Panavia F, Group II: Clearfil SE Bond I Panavia F, Group III: Variolink Hand Group IV: Syntac Sprint I Variolinkll. The mean shear bond strengths for the four test groups were recorded and the data were compared. It was found that the bond strengths increased significantly with the coating of the dentine bonding agents

Comparison of shear bond strength of metal castings luted to dentine using resin cements

The purpose of this study was to investigate the shear bond strength of metal discs luted to dentine. In this study three resin luting cements i.e. Panavia F [Group I], Variolink II [Group II] and Superbond C and B [Group III] were compared to demonstrate which material was more superior to bond sandblasted cobalt chromium alloy to dentine. Groups I, II and III were compared using ANOVA, P < 0.05. Panavia F demonstrated significantly higher bond strengths than Variolink II or SuperBond C and B. SuperBond C and B had significantly higher shear bond strength than Variolink II. Thus, there were significant differences among the tested resin luting cements for bonding metal discs. Panavia F was found to give the highest shear bond strength within the limitations of this study followed by Superbond C and B and Variolink II

Evaluation of sealing ability of three root canal sealers

The purpose of this study was to determine the sealing ability of three different sealers and to compare the sealing ability of three sealers. Thirty single rooted mandibular first premolar teeth were used. The crowns were removed at the cemento - enamel junction and root canals were prepared to a # 35 K-file. The teeth were randomly divided into three groups, A, K and R. Each group consisted of 10 specimens. In group A, AH Plus sealer, group K, Ketac-endo sealer and group R, Roth 801 sealer were used and obturated with gutta percha using lateral condensation technique. After storage in 100% humidity at 37°C for one week, the root surfaces were coated with nail polish [except at the apex] and suspended in 2% methylene blue dye solution for one week. The roots were sectioned longitudinally to determine the following mean values of dye penetration, group A - 2.675 mm, group K - 2.346 mm, group R - 4.929 mm. This study shows that Ketac-endo gave better seal than Roth 801 sealer