Accuracy of the orthopantomogram in assessment of tooth length in orthodontic patients.

The orthopantomogram (OPG) provides as assessment of root length and characteristics before orthodontic tooth movement. This study determined the accuracy of the OPG in assessing tooth length. Investigators compared the radiographic and actual tooth lengths in permanent first premolars indicated for orthodontic extractions. Results showed that the mean lengths measured from OPG were consistently higher than the actual lengths by 22% (p < 0.001) for maxillary teeth and by 1% for mandibular teeth. This study found that there is elongation of root images in OPG.

The effect of smear layer removal on marginal contraction gaps.

The presence of the smear layer prevents direct contact between dentine and a dentine adhesive. The use of agents to remove the smear layer theoretically should improve the bonding of composite resins to dentine. This study examined the effect of smear layer removal on the effectiveness of a dentine bonding agent in reducing marginal contraction gaps. The agent used for smear layer removal in this study was ethylenediamine tetra-acetic acid (EDTA). Eighty cavities measuring 2 mm in diameter and 1.5 mm in depth were prepared in dentine and randomly assigned to two equal groups. The control group was restored with Prisma Universal Bond 2 Adhesive and Prisma Fil Resin. The experimental group was similarly restored after pretreatment of dentine with 0.5% EDTA for 60 s. All specimens were thermocycled and the marginal contraction gaps were assessed using a Nikon Measurescope. The mean contraction gap was expressed as a percentage of the cavity diameter. Results showed that the experimental group registered smaller contraction gaps (mean: 0.021%) than the control group (mean: 0.027%). No penetration of material into dentine was observed. Pretreatment with EDTA did not significantly improve the effectiveness of the dentine bonding agent used in terms of reduction of marginal contraction gaps.

Effect of loading and syringing on void formation in automixed addition silicone elastomers.

The effect of loading and syringing on void formation in five automixed addition silicones was evaluated by determining the voids created in the first and second halves of material loaded and dispensed from a metal syringe. Impressions were made of a model with six stainless-steel cylinders. The voids were counted at a predetermined site on 3 separate days using a binocular microscope at x 7 magnification. Automixed addition silicones did not confirm the 'last out-fewer bubbles' phenomenon and specific loading and syringing technique did not appear to have a consistent effect on void formation in automixed elastomers.

Radiation dosage of a dental imaging system.

This study compared the radiation dosage necessary for obtaining clinically acceptable images with a new dental imaging system (radiovisiography) to that required with a conventional-film radiographic technique. Results showed that radiovisiography required significantly less radiation exposure, only 22.3% of that used in the conventional technique. Problems, such as lack of flexibility and the limited size of the x-ray-sensitive surface, are associated with radiovisiography; however, the system effectively complements conventional-film radiography.

Comparison of two pain rating scales among Chinese cancer patients.

The Simple Descriptive Scale (SDS) has been known to be easier to use, but lacks sensitivity when compared to the Visual Analogue Scale (VAS). In this study, 79 cancer patients quantified the intensity of their pain experience on both the VAS and SDS before receiving pain therapy and on the fifth day after commencing the therapy. High correlations were observed between the two scales in age, sex and types of analgesics. The results demonstrate that the SDS provides a simpler and, perhaps, equally sensitive alternative to the VAS, in measurement of cancer pain among Chinese patients. It would be particularly useful for those with language barriers and/or other factors in understanding the requirements or the VAS.

Variability of two methods of measuring absorbed dose in dental radiography.

Thermoluminescence dosimetry (TLD) has been widely used in the monitoring of radiation exposure in healthcare workers operating radiation devices. This study compared the reliability of TLD to an electronic dosimeter. The absorbed dose registered by the TLD chips was found to be higher than that by the electronic dosimeter. Variability was found to be significantly higher and the variance component attributed to the variability of the method of measurement was more than twice as much in TLD when compared to the electronic dosimeter. It is concluded that TLD is a more variable method of measuring absorbed dose than the electronic dosimeter.

Racial differences in perception of oral health and oral health behaviours in Singapore.

Knowledge of prevention can influence preventive dental behaviours. This study surveyed knowledge and preventive dental behaviours on the prevention of dental caries and gum disease among the adult population of the three major racial groups in Singapore. Respondents were asked to rate the importance of several preventive measures against dental caries and gum disease. Questions were also fielded on dental behaviours such as preventive visits to the dentist, toothbrushing and flossing. Results showed that there was a general lack of appreciation for the use of flossing, dental sealants and fluoride supplements. Although a majority of respondents thought that regular dental checkups would be essential for prevention, the proportion who actually saw the dentist for preventive care was significantly lower. Respondents provided inappropriate reasons for brushing their teeth. Differences in both preventive knowledge and preventive dental behaviours among racial groups were evident although these were attributed to differences in education and exposure to product information rather than to racial or cultural factors.

Ranking of facial profiles among Asians.

The purpose of this study was to determine the facial profile preferences in a sample of 1,189 Asian teenagers (aged 15.3 +/- 3.2 years). Five facial profile types were computer-generated by trained personnel (orthodontists and oral maxillofacial surgeons) to represent distinct facial types. Subjects were asked to rank the profiles in descending order of attractiveness. The ranking was as follows: orthognathic profile, bimaxillary retrusive profile, bimaxillary protrusive profile, mandibular retrognathic profile, and mandibular prognathic profile. The differences in rank scores between all the profile types were statistically significant (p < 0.05). Assessment of profile types among lay personnel could provide clinicians an indication into the relative attractiveness among profile types and health care workers in treatment prioritization among dysmorphic facial types.

Dental prosthetic status and needs of an elderly population living in long-term care facilities in Singapore.

This study examined the prosthetic status and needs among an elderly population living in long-term care facilities in Singapore. A total of 488 subjects were randomly selected and 479 of them were examined. The results show that 56.2 percent of selected subjects were edentulous while 43.8 percent had one or more teeth missing. The average number of teeth present among dentate subjects was 7.5. Of the edentulous subjects, 78 percent of them reported not having any dentures, and more than 20 percent of existing dentures were found to be defective and had to be replaced. A higher proportion (94 percent) of dentate subjects who could have benefitted from having partial dentures did not have them. The findings of this study clearly demonstrate high unmet needs for prosthetic care among an institutionalized elderly population.

Phases of dental fear for four treatment procedures among military personnel.

Dental fear is a significant problem in the delivery of dental care. This study examined the phases of dental fear in 488 military conscripts scheduled to receive four categories of dental treatment for the first time. Results showed that the level of fear increased gradually from the day before treatment and peaked while receiving it. A significant reduction occurred after completing the treatment. Among the different types of procedures, tooth extraction elicited the highest degree of fear, while having the teeth cleaned registered the lowest. Military servicemen showed a pattern of dental fear similar to those other population groups.

Disparity between medical and dental care of institutionalised elderly in Singapore.

Elderly persons tend to give dental care a lower priority than medical care. This study examined existing arrangements for and financial support of dental and medical care to elderly persons living in 68 long-term care facilities in Singapore. The chief administrators of all the homes for the aged were interviewed regarding the provision of physical and financial access to dental and medical care for their residents. Information was verified with a random selection of their residents. Results showed that a significantly higher number of homes (93 per cent) assumed responsibility for the provision of medical care than for dental care (70.7 per cent). A significantly greater proportion of them offered in-house medical care (42.6 per cent) than in-house dental care (5.9 per cent). Financial support for payment of providers' fees, hospitalisation and the transportation costs of ambulatory visits for both medical and dental care was found to be similar but generally inadequate. Greater commitment towards improving physical and financial access to dental care for the institutionalised elderly is necessary.

Understanding prevention of dental caries and gum disease in the singapore population.

Prevention has been recognized as a cost-effective method for the control of oral diseases. Knowledge of prevention can influence preventive dental behavior. This study surveyed knowledge on the prevention of dental caries and gum disease among a selected group of adults. Respondents were asked to indicate the importance of numerous preventive measures for prevention of both categories of oral diseases. Results showed that while respondents appropriately identified the importance of regular brushing for prevention, the role of flossing is underestimated. Similarly, there was a lack of appreciation for the value of various fluoride treatment modalities in preventing dental caries. A lack of understanding of dental sealants was also evident. It is concluded that public knowledge on prevention of dental caries and gum disease deviates greatly from current scientific information.

Assessment of orthodontic treatment needs by teenagers in an Asian community in Singapore.

The purpose of this study was to determine (1) the preference of dental occlusion types among teenagers, and (2) their assessment of the necessity for orthodontic treatment. A total of 1189 teenagers (mean age 15.3 +/- 3.2 years) were asked to rank a series of colour photographs of seven occlusion types. Their ranking, in descending order of attractiveness, were as follows: Class I occlusion, anterior open bite, Class III occlusion, Class II occlusion, anterior spacing, anterior crowding and deep bite occlusion. The perceived need for treatment was found to be inversely correlated with the rank order of attractiveness. There appeared to be no statistical difference (P less than 0.05) in the perception for treatment among different racial and income groups. However, with the exception of anterior open bite and deep overbite occlusions, a statistically significant (P less than 0.05) greater number of females than males perceived a need for treatment. Assessment of occlusal disharmonies among teenagers could provide clinicians and health care personnel with an indication of the relative attractiveness among occlusion types and hence the establishment of treatment priorities.

Medical care for institutionalised elderly people in Singapore.

This study examined physical and financial arrangements for medical care of institutionalised elderly people in Singapore. Chief administrators of all long-term care facilities were interviewed on the existing arrangements for medical care of their residents. Results showed that 66 out of a total of 68 (97%) homes arranged medical care for residents. Of those, 29 homes offered on-site medical care with alternative arrangements when the in-house facilities were not operating. While government-owned homes would pay for all medical costs incurred by their residents, over 48% of voluntary homes and 87% of commercial homes required residents to be financially responsible for their care. The availability of financial support given to residents for payment of medical care was found to be associated with the type of sponsorship of the homes. While there was adequate physical access to medical care, the lack of financial support would pose a potential barrier to use of medical care for institutionalised elderly people.

Dental state and needs for episodic care of institutionalized elderly in an Asian community.

This study examined the dental state of institutionalized elderly and their need for care. An oral examination was carried out on 479 elderly persons living in long-term care facilities with a mean age of 74.9 years. Results showed an overall DMF score of 27.0 and the average number of teeth in dentate subjects was 7.5. A large proportion of teeth (76.6%) was lost through dental caries and the loss increased significantly with age. Consequently, 56.1% of subjects were edentulous, of whom 78.8% were without dentures. Among the conditions that required urgent dental care, majority of subjects needed extractions of residual roots and loose teeth. A lesser proportion required treatment for gross caries (4.8%), periodontal disease (5.0%), suspected tumor (0.2%), as well as alleviation of pain and infection arising from mucosal lesions (4.8%), abscesses (3.3%) and TMJ problems (2.8%). The treatment needs for dentures and episodic care are high among institutionalized elderly and need to be addressed.

Effect of operator variability on void formation in impressions made with an automixed addition silicone.

This study examined voids produced in impressions of an automixed addition-reaction silicone. Two operators took the impressions using material dispensed from either intra-oral tips or an impression syringe. The material was also hand-mixed for comparison. There were no differences in the number of voids in the automixed material dispensed using the intra-oral tip or impression syringe. Automixing produced substantially fewer voids than hand-mixing. There was a significant difference in the number of voids in the impressions made by the two operators.

Effects of explanation of treatment procedures on dental fear.

Dental fear has been described as anticipation anxiety. This study examined the effectiveness of providing pertinent details of treatment procedures to reduce the level of dental fear for dental checkups, prophylaxis, restoration and extraction in 306 fearful patients. Measurements of pre-treatment and post-treatment levels of fear showed a significant reduction in dental fear in all four procedures. Results showed that a better understanding of treatment processes reduced levels of dental fear in fearful patients.

Quantification of noble alloy used in 'porcelain-fused-to-metal' restorations.

High costs of gold alloys used in metal substructures of ceramo-metal restorations increase the cost of restorative treatment. This study determined the per unit weight of a noble metal alloy used in ceramo-metal crowns and three-unit fixed-partial dentures. Generally, tooth size and extent of the metal substructure determined the quantity of alloy used.

An evaluation of exposure time and temperature in the thermocycling of dental restorative materials.

This study indicates that some current procedures used in thermocycling dental restorative materials would not produce the desired thermal gradient in the specimens. The shortfall in gradient depends on the size of the specimen, the dwell time in the baths and whether the baths are stirred or not. The desired thermal gradient of 50 degrees C can be approximated with a dwell time of 60 s in well-circulated water baths at 5 degrees C and 55 degrees C. For critical studies a dwell time of 90 s is recommended.