Strategies for Oral Health Research in Africa and the Middle Eastern Region.

The highest burden of diseases worldwide is in low- and middle-income countries, but due to lack of capacity and inadequate infrastructure, research output from these countries is unable to address existing and emerging challenges in health care. Oral health research has particularly been hampered by low prioritization, resulting in insufficient development of this sector. There is an urgent need for research correlating oral health to upstream social and environmental determinants and promoting the common risk factor approach for prevention of noncommunicable diseases. Population-wide preventive measures for oral health care are more effective than purely curative approaches, especially for vulnerable groups who have limited access to information and appropriate health care. This article identifies priorities and proposes strategies for researchers, stakeholders, and policy makers for the initiation and sustenance of appropriate oral health care research. The proposed interventions are intended to promote collaboration, capacity building, and health advocacy. Local ownership in multinational research projects in low- and middle-income countries, complemented by skills transfer from high-income countries, is encouraged to ensure that regional health needs are addressed. Emphasis is placed on a shift toward translational research that has a direct impact on oral health care systems.

Factors associated with severe caries among adults in Kuwait.

AIM: To investigate the relationship between caries etiological factors and occurrence of severe caries among adults in Kuwait. METHODS: Forty-two adult patients with severe caries, attending Kuwait polyclinics, were compared with 36 caries-free subjects in a cross-sectional study. The patients with severe caries were aged 16 years or older and had a minimum of eight open coronal carious cavities, with the involvement of at least one anterior tooth. In addition, their salivary glands had not been compromised by disease or medication. The caries-free subjects had at least 24 standing teeth, and no carious cavities. Salivary flow rates, buffering capacity, frequency of sugar consumption, and oral hygiene index were measured. Mutans streptococci and Lactobacillus counts were determined by the dip-slide method. RESULTS: Fisher's exact test or chi(2) test showed that the patients with severe caries had a significantly higher frequency of sugar consumption, plaque index, Lactobacillus and mutans streptococci counts, as compared with those who were caries-free. In contrast, no significant difference was observed in salivary flow rates or buffering capacity between the two groups of patients. In the multiple logistic regression analysis, only frequency of sugar consumption, oral hygiene, and mutans streptococci count were found to be significantly associated with the occurrence of severe caries. CONCLUSION: Severe caries may occur in Kuwait even among adults whose salivary gland functions have not been compromised.

Fluoride ingestion from drinking water by Nigerian children aged below 10 years.

AIMS: To determine daily fluoride ingestion from drinking water by Nigerian children aged below 10 years using two different methods of measurement. METHODS: The mean daily water consumption by 314 children was determined and fluoride levels in drinking water sources measured in northern and southern zones of Nigeria. From the results, daily fluoride ingestion by the children was calculated. RESULTS: The mean daily water consumption was 1.7 (SD0.4) litres in 1-3-year-olds and 2.6 (SD0.5) litres at age 7-9 years in the North; but the corresponding values were significantly lower in the South (p<0.05). However, the mean body weights of the children were significantly lower in the North (p<0.05), being 11.5 (SD 2.5) kg in 1-3-year-olds. The mean daily fluoride ingestion by children aged 1-3 years exposed to 0.7 ppm F (recommended for the tropics) was calculated to be 0.062 (SD0.023) mg/kg body weight in the South, and this is within the range of 0.04-0.07 mg/kg body weight generally regarded as appropriate. In contrast, ingestion of the ion by similarly aged children exposed to the same fluoride level in the north was higher than the threshold dose. CONCLUSION: It is, therefore, concluded that exposure to drinking water containing recommended fluoride levels in the tropics (northern zone of Nigeria) could result in ingestion of a fluoride dose higher than the threshold that is generally regarded as appropriate.

Caries prevalence and its relation to water fluoride levels among schoolchildren in Central Province of Saudi Arabia.

OBJECTIVE: To determine dental caries prevalence and severity among primary and intermediate schoolchildren in Riyadh and Qaseem Regions, and to determine any correlation between dental caries and fluoride levels in drinking water. DESIGN: Cross-sectional. METHODS: 1,104 children; 431 (6-7-year-old) primary schoolchildren (249 in Riyadh and 182 in Qaseem) and 673 (12-13-year-old) intermediate schoolchildren (392 in Riyadh and 281 in Qaseem) were examined for dental caries utilising the WHO criteria for diagnosis of dental caries. RESULTS: In primary schoolchildren the prevalence of caries was 91.2% both in Riyadh and Qaseem. The mean dmft scores were similar in Riyadh (6.53, SD 4.30) and Qaseem (6.35, SD 3.83). Among the intermediate schoolchildren the prevalence of dental caries was slightly higher in Riyadh (92.3%) than Qaseem (87.9%). The mean DMFT score was higher in Riyadh (5.06, SD 3.65) as compared with Qaseem (4.53, SD 3.57) with marginal statistical significance (p = 0.057). Among the primary schoolchildren there was statistically significant (p < 0.05) difference in mean dmft scores at various fluoride levels with lowest dmft scores at the optimum water fluoride level (0.61-0.80ppm) and highest at two extremes i.e. 0.0 to 0.3ppm and > 2.5ppm, while in intermediate schoolchildren no significant difference in overall mean DMFT scores of children at various water fluoride levels could be found. CONCLUSION: The caries experience among the primary and intermediate schoolchildren in Riyadh and Qaseem was very high, and that there was no linear correlation between water fluoride level and caries experience in these children.

Oral health in Nigeria.

Most oral health surveys in Nigeria have been sporadic and based on convenience samples. Periodontal disease with deep pocketing occurs in Nigerians at an early age, the prevalence being 15-58% in those aged above 15 years. Caries experience has been reported to vary between very low and low in most studies, but is moderate in some urban communities. Although mean DMFT is below 4 in most communities, the restorative index is extremely low, most carious teeth remaining unrestored. The higher caries prevalence in second than first permanent molars that has been reported is most likely due to a change from traditional to Western-type diet. Other oral health problems include malocclusion, truamatised teeth, dental fluorosis, and oral tumours. The scanty oral health services available in the country are mainly in urban areas. There is, therefore, a need to develop sustainable strategies for national preventive and therapeutic oral health services in Nigeria.

Penetrability of dentinal tubules in adhesive-lined cavity walls.

This study investigated the penetrability of dentinal tubules in cavity walls lined with different dentin bonding systems. Occlusal Class I cavities were prepared in 93 premolars. The cavities in the control group had an intact smear layer without a lining, while those in the experimental group were lined with Gluma CPS, Scotchbond Multi-Purpose Plus or One-Step. The penetrability of the dentinal tubules was tested with a dye (basic fuchsin) or bacteria (S faecalis) immediately after adhesive lining and after one-month storage in water at 37 degrees C. Some of the lined samples were sectioned and examined under the SEM. In some samples in the experimental group, the dye penetrated to the pulp and bacteria up to 125 microm into the dentinal tubules immediately after lining. The Kruskal Wallis ANOVA and Tukey test showed the depth of dye and bacterial penetration to be significantly less in teeth with bonding systems than those in the control group (p<0.05). However, there was no statistically significant difference between the control and experimental groups after storage in water (p>0.05). SEM examination showed that the hybrid layer and resin tags were present in the cavity walls immediately after lining but absent after storage in water. Therefore, adhesive linings under the experimental conditions were ineffective in preventing dye or bacterial penetration of the dentinal tubules.

Occurrence and management of dental fluorosis.

The prevalence of dental fluorosis is on the increase in different parts of the world, even in areas with fluoride-deficient public water supplies. This may be due to increased use of fluoride in preventive dentistry. In some countries, exposure to apparently low fluoride concentrations in drinking water has resulted in severe dental fluorosis in some children. This underscores the importance of taking into consideration all sources of fluoride intake in a community before prescribing fluoride supplements or recommending appropriate fluoride concentration for the public water supply. Preventive management of dental fluorosis includes de-fluoridation of drinking water in endemic areas, cautious use of fluoride supplements and supervision of the use of fluoride toothpaste by children aged below 5 years. Aesthetically objectionable discolouration of fluorosed teeth may be managed by bleaching, micro-abrasion, veneering or crowning. The choice between these treatments depends on the severity of the fluorosis and this may be satisfactorily determined by the Thylstrup and Fejerskov index.

Post-operative sensitivity in glass-ionomer versus adhesive resin-lined posterior composites.

PURPOSE: To compare objective and subjective assessments of post-operative sensitivity when class 1 cavities, lined with glass-ionomer or adhesive bonding system, were restored with resin-based composite (RBC). MATERIALS AND METHODS: Occlusal cavities on homologous contra-lateral posterior teeth in 44 male patients attending primary health centers in Riyadh, Saudi Arabia were restored with RBC after a cavity lining of either a light cured glass-ionomer cement (Vitrebond) or an adhesive bonding system (One-Step). RESULTS: Cold response measurements 24 hrs, 7 days and 1 month post-operatively showed that the threshold of pulpal response was significantly lower (P< 0.05) in the restored teeth when the adhesive bonding system served as cavity liner. In addition, based on the patients' subjective assessments, the prevalence of mild or severe post-operative sensitivity was significantly higher (P< 0.05), 24 hrs and 7 days post-operatively, in the teeth with the adhesive bonding system as a cavity liner. After a post-operative period of 1 month, however, there was no significant difference (P> 0.05) between the prevalence of post-operative sensitivity when the restored teeth received a lining of either glass-ionomer or adhesive bonding system.

Effect of fluorosis on etching of human enamel.

To investigate the effect of fluorosis on the pattern and depth of etch of human enamel, 420 enamel specimens classified according to the Thylstrup and Fejerskov index (TFI) were etched with 37% phosphoric acid for varying times. The mean depths of etch for mildly fluorosed enamel (TFI = 1-3) were generally dependent on etching time (r = 0.55-0.76), and were not significantly different from the depth obtained for non-fluorosed (TFI = 0) specimens. The enamel specimens with more severe fluorosis (TF = 4) required longer etching time which showed little correlation with the mean depth of etch (r = 0.15-0.16). Furthermore, the etched specimens showed typical enamel etching patterns, independent of the severity of fluorosis. When the specimens with TFI = 4 were etched for 45 s, the subsurface organic network was evident, but this disappeared and typical etching patterns could be seen again when etching time was increased to 75-90 s. It is therefore concluded that the diagnosis of the severity of fluorosis must first be made whenever etching of fluorosed enamel is contemplated.

Effect of fluorosis on shear bond strength of glass ionomer-based restorative materials to dentin.

STATEMENT OF PROBLEM: Several studies have investigated the adhesion of glass ionomer-based restorative materials to nonfluorotic teeth, but there appears to be no information on the bond strength of these restorative materials to dentin in fluorotic teeth. PURPOSE: This study investigated the effect of dental fluorosis on the bond strength of Ketac-fil conventional glass ionomer cement, Vitremer resin-modified glass ionomer cement, and Dyract polyacid modified resin to dentin. MATERIAL AND METHODS: Ninety posterior teeth were classified according to the severity of fluorosis, by using the Thylstrup and Fejerskov index, TFI. The teeth were divided into 3 equal groups (TFI = 0,TFI = 1-3, TFI = 4+) of 30 teeth, which were again divided into 3 equal subgroups for testing each of the3 restorative materials. Occlusal surfaces of mounted teeth were ground flat to expose dentin. Cylindrical specimens (4 mm diameter and 4 mm high) of the restorative materials were bonded to the middle of the cleaned exposed dentin surfaces, according to the manufacturers' instructions. After storing the specimens in 100% humidity at 37 degrees C for 24 hours, shear bond strengths of the restorative materials were measured with an Instron testing machine at crosshead speed of 0.5 mm/min. RESULTS: Two-way analysis of variance and Tukey-B test revealed that Dyract had significantly higher shear bond strength to dentin than Ketac-fil or Vitremer cements, regardless of severity of fluorosis (P <.05). Furthermore, there was an inverse relationship between shear bond strength and the severity of fluorosis for each of the restorative materials. Cohesive mode of failure was most prevalent in nonfluorotic teeth (TFI = 0), especially with Ketac-fil cement, whereas Dyract cement had the greatest propensity for adhesive failure. CONCLUSION: Fluorosis reduces the shear bond strength of glass ionomer-based restorative materials to dentin.

Dental fluorosis in 12-15-year-old rural children exposed to fluorides from well drinking water in the Hail region of Saudi Arabia.

To investigate the relationship between fluoride levels in well drinking water, severity of dental fluorosis and dental caries in the Hail region of Saudi Arabia, 2355 rural children aged 12-15 years were examined. Over 90% of the children had fluorosed teeth and chi-square tests showed a strong association (P < 0.001) between fluoride level (0.5-2.8 ppm) in well drinking water and severity of dental fluorosis. Although regression analysis showed a statistically significant relationship (P < 0.001) between fluoride concentration and caries experience, the amount of variation explained was very low (R2 = 0.9%). Since fluoride in well water had little influence on caries experience and is causing dental fluorosis, it should be removed by defluoridation or the rural population should be provided with an alternative source of drinking water with lower fluoride concentration.

Cavitation at radiolucent areas on proximal surfaces of posterior teeth.

To investigate the factors that influence the probability of clinical cavitation at radiolucent areas of proximal surfaces of posterior teeth, 108 molars and premolars with varying depths of proximal radiolucency were examined clinically, after cavity preparation on the carious contiguous tooth surfaces. The data obtained were subjected to logistic regression analysis with cavitation as the dependent variable, while age, tooth type and past caries experience (DMFT and DFS) were independent variables. When proximal radiolucency was confined to the outer half of enamel, there was no cavitation, but when it extended to the amelodentinal junction and the outer and inner half of dentine, there was cavitation in 19.3, 79.1 and 100% of cases, respectively. Moreover, there was a statistically significant relationship between the probability of cavitation, depth of radiolucency and age, suggesting that these should be among the main factors considered when restorative management of a radiolucent proximal surface of a posterior tooth is contemplated.

Dental caries, sugar consumption and restorative dental care in 12-13-year-old children in Riyadh, Saudi Arabia.

A 3-day dietary history was obtained from 363 Riyadh schoolchildren aged 12-13 yr, after which their dentitions were examined for dental caries. About 16-31% of the children were caries-free and the mean DMFT varied between 1.67 and 2.43. However, in those with at least one tooth decayed, missing or filled, the mean DMFT remained constant at about 3, irrespective of age or gender; and most of the carious teeth were unrestored. There was a statistically significant relationship between DFS and the frequency of sugar consumption on the first 2 days of the dietary diary. It is suggested that the management of dental caries in the children must include the control of dietary sugar.

Replication of human occlusal tooth attrition surfaces for scanning electron microscopic study.

Silicone negative replicas of dentine islands exposed by occlusal attrition were examined on extracted human teeth using the scanning electron microscope. Because the details of the dentinal tubules were reproducible on the silicone impression, the replication technique was applied in vivo to occlusal attrition to demonstrate patent dentinal tubules in cases with symptomatic exposed dentine islands. using this replication technique, it should be possible to monitor the effect of the therapeutic management of symptomatic tooth attrition on dentinal tubule closure.

An evaluation of a workshop on educational methods for health science teachers in Lagos, Nigeria.

A workshop on educational methods held at the College of Medicine, University of Lagos in 1980 was evaluated by means of questionnaires. The workshop was favourably received and enhanced the teaching practices of participants. As a result of the workshop, most participants wrote instructional objectives, used more audiovisual aids and adopted new methods of teaching and assessment of clinical skills. Although the session on the production of self-instructional packages (SIPs) was rated highly at the workshop, relatively few participants had completed a programmed text at time of follow-up. Similarly, most participants had set MCQs but few had calculated either the facility or discrimination index. The participants themselves suggested that future workshops should be tailored to the particular educational needs of different disciplines. The authors suggest that intensive short-term workshops may be useful for content areas which require more time than an extensive workshop permits.

Bacterial invasion of pulpal dentin wall in vitro.

Instrumented root canals of extracted human teeth were inoculated with known pulpal bacterial isolates. The inoculated teeth were immersed in the appropriate culture media and incubated at 37 degrees C for varying periods. Streptococci multiplied in the root canals and invaded the radicular dentinal tubules. The extent of bacterial invasion was time-dependent. This experimental model of bacterial invasion was time-dependent. This experimental model may be useful in investigating the effect of intra-canal medicaments on microorganisms lodged in the pulpal dentin wall.