Biomedical subjects

A Ogunyinka

Publications and source records attributed to A Ogunyinka.

13 recordsLinked to original sources

PubMed2006

Photoinitiation chemistry affects light transmission and degree of conversion of curing experimental dental resin composites.

INTRODUCTION: The effect of photoinitiator and co-initiator chemistry on the setting reaction and degree of conversion of dental resin-based composites (RBCs) has rarely been determined explicitly. This work examines the effect of type and concentration of photoinitiator and co-initiator on the rate of change of light transmission throughout polymerisation and degree of conversion of model RBC formulations. METHODS: Bisphenol-A diglycidyl ether dimethacrylate (bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) (6:4 molar ratio) resins filled with silanized glass filler (74wt.%) and containing various photoinitiators (camphorquinone; CQ, 1-phenyl-1,2-propanedione; PPD, benzil; BZ), co-initiator types (N,N-dimethyl-p-amino benzoic acid ethyl ester; DABE, N,N-cyanoethyl methylaniline; CEMA, N,N-diethanol-p-toluidine; DEPT) and concentration (0.0-0.3% DABE) were polymerised using a halogen or LED light curing-unit (LCU) for 10, 20 and 40s. The setting reaction was monitored in real-time by measuring the light transmittance through the curing specimen and bulk degree of conversion (DC) evaluated using Fourier transform infra-red spectroscopy. RESULTS: Specimens containing CQ and PPD cured with the halogen LCU did not have a significant effect on DC or changes in light transmission, although a significant increase in DC was observed for CQ compared with PPD specimens cured with the LED LCU. DABE and CEMA were more effective co-initiators than DEPT. Although DC was not limited by co-initiator concentration, the absence of a co-initiator resulted in marked differences in light transmission and decreased DC throughout 40s irradiation with each LCU type. CONCLUSIONS: The spectral range emitted from different types of LCU and absorption characteristics of the photoinitiator chemistry of light-activated resin-based composites play a critical role in the efficiency of polymerisation.

Analysis of Variance↗

PubMed2005

Tooth wear in the elderly population in South East Local Government area in Ibadan, Nigeria.

It is the aim of this study to determine the pattern and degree of tooth wear in the elderly population in the South East Local Government Area in Ibadan. The study was carried out on 690 elderly individuals who were 65 years old and above, living in various wards in South East Local Government Area, in Ibadan. A multistage sampling technique was used to select elderly individuals for the study. Two interviewers, 2-record clerks and 2 examiners were trained for the study and the examiners were calibrated. The index of Eccles J.D was used to determine the severity of tooth wear. The results highlight the high prevalence of tooth wear, mainly attrition in the elderly in this local government area. Six hundred and forty (92.8%) of the elderly had tooth wear. Of these 58.59% were males and 41.41% females. Attrition was observed in 618 (89.6%) elderly individuals. The mandible exhibited a higher prevalence of tooth wear than the maxilla and was statistically significant. Severe tooth wear was observed in only 5.74% of the teeth whilst moderate and mild tooth wear were observed in 26.91% and 30.88% respectively. Unlike the Western European countries, attrition being the most common type of tooth wear in these elderly individuals suggests that the aetiological factors responsible for tooth wear are different. Common habits such as crushing of bones and chewing of sticks for routine oral hygiene care could be contributing factors to tooth wear in this environment.

Aged↗

PubMed2001

The pattern of toothwear amongst 12-18-year-old students in a Nigerian population.

The purpose of this study was to investigate the pattern of toothwear in the permanent teeth of 12-18-year-old Nigerian students. The study group comprised 176 individuals (67 males and 109 females) who had no carious cavity, restoration or fracture on any of their permanent teeth. Within the group, 86% had tooth surface loss that was limited to enamel and dentine. No statistically significant differences were observed between the sexes. The most commonly affected tooth was the lower first molar, while the occlusal surface was the most frequently involved. One student had toothwear with a predominantly erosive component as a result of frequent ingestion of low pH drinks, while another displayed toothbrush abrasion. Of those with toothwear, two (13.4%) had parafunctional activities. The cause of toothwear in 73.2% of the study population could not be ascertained. Some of it may be connected with the coarse, abrasive diets that many of the students admitted to consuming on a regular basis.

Adolescent↗

PubMed2000

The bond of two adhesive resins to alumina blasted and heat-treated gold alloy surfaces.

The purpose of this study was to test in shear mode the bond strengths of two BIS-GMA resin cements bonded to alumina blasted and heat-treated gold alloy surfaces. This was carried out in order to investigate the manufacturer's claim of the superiority of Panavia 21 over Panavia Ex. Alumina blasted gold alloy surfaces were cemented in pairs with either Panavia Ex or Panavia 21 resin cements. Heat-treated gold alloy surfaces were similarly paired. The luted pairs were stored in water at 37 degrees C for 48 h before bond was tested with shearing forces. Although the differences were not statistically significant, it was found that Panavia 21 formed stronger bonds on the alumina blasted surfaces than Panavia Ex. However, Panavia Ex exhibited higher mean strength values than Panavia 21 on the heat-treated surfaces. Not only was this difference statistically significant, but the bond strength values obtained for Panavia Ex on this surface were the highest in the data set. On the basis of bond testing in shear, it would appear that Panavia 21 is inferior to Panavia Ex on heat-treated gold alloy surfaces.

Aluminum Oxide↗

PubMed2000

Bond strengths and patterns of failure of a zinc polycarboxylate cement on surface-treated gold alloys.

The study investigated the shear strengths and fracture characteristics of a zinc polycarboxylate cement on three sets of type III gold alloy bars whose surfaces were modified by alumina blasting, heat treatment and tin plating respectively. Each set comprised 20 bars with similarly treated surfaces, cemented in pairs with the polycarboxylate cement and stored in water at 37 degrees C for 48 hours. The cement bond was then stressed to failure by application of forces in shear mode and the bond strength was determined. The mean bond strength for each type of treated gold alloy surface was calculated and then compared with the others by way of statistical analysis. The failed surfaces were observed and photographed with a stereophotomicroscope for subjective evaluation of the character of the failed surfaces. The strongest bonds were formed on the alumina-blasted surfaces where 70% of the bonds failed in an adhesive-cohesive fashion. The weakest bonds were formed on the tin-plated surfaces where cement failure was entirely adhesive. Bond strengths on the heat-treated surfaces were intermediate and a cohesive failure pattern was observed on 80% of the specimens. The differences in bond strengths on the three surfaces were statistically significant.

Adhesiveness↗

PubMed1999

Malocclusion and orthodontic treatment need of secondary school students in Nigeria according to the dental aesthetic index (DAI).

The aims of this study were to measure the distribution, prevalence and the severity of malocclusion and treatment need amongst randomly selected (n = 703) rural and urban Nigerian children aged 12-18 years (mean 14.0 +/- 1.84) using the dental aesthetic index (DAI), and to assess whether malocclusion was affected by age, gender and socio-economic background. Data were collected according to the method recommended by WHO. Most of the children (77.4 per cent) had a dental appearance which required no orthodontic treatment. Over 13 per cent fell into the group where treatment for malocclusion is considered to be 'elective'. However, a substantial proportion (9.2 per cent) of the population had severe to handicapping malocclusion where treatment is 'highly desirable' or 'mandatory'. There were no statistically significant differences (P > 0.05) in DAI scores between age groups, gender and socio-economic background. This study also found that Nigerian adolescents had better dental appearance and less orthodontic treatment need compared with the Caucasian and Oriental populations.

Adolescent↗

PubMed1998

A simple method of increasing the adhesion between resinous cements and tinplated gold alloys: a pilot study.

PURPOSE: This study: (1) tested 2 BIS-GMA resinous cements on tinplated gold alloy surfaces with shearing forces to record their bond strengths, and (2) determined whether storage of the tinplated surfaces in water before cementation affected initial bond strengths. MATERIAL AND METHODS: The bond strengths of Panavia Ex and Panavia 21 resinous cements to tinplated Type III gold alloy were measured when subjected to shearing forces. Specimens were luted in pairs with these cements. In one group, the cementation was performed after tinplating procedures. In the other group, tinplated alloy surfaces were first stored in water at 37 degrees C for 48 hours before cementation. RESULTS: A 3-fold increase in bond strength values was recorded for tinplated specimens stored in water before cementation with both cements, these differences were statistically significant. Storage of the specimen in water before cementation appeared to increase resistance of the alloy resin bond to failure with application of shearing forces. CONCLUSION: This pilot study suggested that it would be advantageous to age tinplated gold alloy surfaces in water for 48 hours before cementation.

Bisphenol A-Glycidyl Methacrylate↗

PubMed1998

Perceptions of dental aesthetics in the United States and Nigeria.

The standard dental aesthetic index (DAI) is an orthodontic treatment need index based on perceptions of dental aesthetics in the United States. It is a regression equation that links perceptions of the social acceptability of dental aesthetics with the objective intraoral measurements of ten occlusal traits. For the index to be universally acceptable, the perceptions of dental aesthetics in other countries must be similar to those of the United States. This study was designed to determine whether the perceptions of dental aesthetics of Nigerian students are similar to those of different groups of the US population. The same 25 stimuli (photographs of dental configurations, a subset of the 200 stimuli used in deriving the standard DAI equation) were rated for dental aesthetics by Nigerian students. Their ratings were compared with ratings of the same 25 stimuli by US parents, students and orthodontists. Spearman rank-order correlations ranged from 0.75 to 0.84. These correlations were highly significant (P<0.0001), and showed that the perceptions of dental aesthetics of Nigerian students were very similar to those of the US groups. The study therefore concluded that standard DAI could be used as a screening tool and without modification in epidemiological surveys among Nigerians.

Adolescent↗

PubMed1996

Localized enamel hypoplasia: a case report.

This case report describes a disfiguring hypoplastic maxillary right central incisor in a 20-year-old man. The maxillary primary central had been traumatized in a fall, which had resulted in its intrusion with subsequent episodes of pain and swelling around the tooth. The tooth had been extracted several years later. When the permanent central incisor erupted, it was grossly hypoplastic. The possible causes of this defect are discussed.

Adult↗

PubMedDate not supplied

Replantation of avulsed teeth: considerations and complications.

Avulsion of teeth is a traumatic dental injury which can be managed by replantation. Important considerations for successful replantations are highlighted. Several sequelae to replantation are discussed in relation to the clinical features observed in a patient seen 6 years after replantation of two avulsed upper incisors. Many of these complications might have been avoided if the patient had returned to the clinic for root canal therapy shortly after the teeth was replanted.

Adult↗

PubMedDate not supplied

Enamel staining and hypoplasia due to multiple causes in a Nigerian adolescent: report of a case.

The aim of this report is to discuss the effects of childhood drug ingestion and metabolic disturbances of ill health in childhood on the coloration, structure and therefore the aesthetics of permanent dentition. To illustrate this, the report presents a case of a 15 year old Nigerian girl with combined tetracycline staining and chronological enamel hypoplastic defects on her teeth. The relationship between the clinical appearance of her teeth and her childhood medical and drug history are analysed. The various treatment modalities available for the management of the dental anomalies are discussed along with the rationale for the treatment given. Strategies for the prevention of these conditions are emphasised.

Adolescent↗

PubMedDate not supplied

Oral complications of cancer treatment.

This report describes the oral complications that may occur in patients who have undergone radiotherapy of the head and neck for the treatment of cancer. It highlights modalities available for reducing and managing these treatment-related consequences. It also discusses the difficulties encountered by the dental health professional providing care for these patients.

Adult↗

PubMedDate not supplied

Amelogenesis imperfecta: a case report.

A case of amelogenesis imperfecta in a Nigerian is presented. Although the patient had almost full complement of teeth, their structure was physically weak and many of them were discoloured. Many of the teeth had lost their enamel and worn down rapidly causing great sensitivity, pain and aesthetic problems for the patient. The clinical features and management of this case are discussed.

Adult↗