Journal of Dentistry

Published by Elsevier
Print ISSN: 0300-5712
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The basic rationale and approach to undertaking a research project are outlined. Selection of a project and the establishment of a working hypothesis and research criteria are discussed. The importance of repeated assessment and critical appraisal of research work is emphasized.
 
– Summary of age and gender: for subjects who completed the six-week clinical study. 
– Summary of the air blast hypersensitivity scores for subjects who completed the six-week study. 
Objective: Evaluate the efficacy of 0.8% arginine, potassium nitrate and sodium fluoride mouthwashes on dentine hypersensitivity reduction. Methods: Six week randomized, double blinded, two cell, parallel single centre clinical study in the Dominican Republic; subjects were randomized into three treatment groups: mouthwash containing 0.8% arginine, PVM/MA copolymer, pyrophosphates, and 0.05% sodium fluoride in an alcohol-free base (arginine); mouthwash containing 2.4% potassium nitrate and 0.022% sodium fluoride (potassium nitrate); a control mouthwash containing 0.05% sodium fluoride (negative control). Tactile and air-blast dentine hypersensitivity assessments were conducted at baseline, thirty minutes post rinsing and two, four, and six weeks of twice-daily product use. For treatment group comparisons, ANCOVA and post hoc Tukey's pair-wise comparisons (α=0.05) were done. Results: Seventy-five subjects were enrolled; 69 subjects completed the study. There were no differences after thirty minutes of a single use, among the three groups with respect to mean tactile and air blast hypersensitivity scores compared to potassium nitrate and negative control mouthwashes (p<0.05). The arginine group presented a statistically significant improvement in the mean tactile scores compared to potassium nitrate and negative control groups after two, four, and six weeks (p<0.001) of product use; the arginine group showed a statistically significant enhancement in air blast hypersensitivity mean scores compared to potassium nitrate and negative control groups after two (p=0.001), four (p<0.001), and six weeks (p<0.001) of product use. Conclusion: A mouthwash containing arginine provides a significant and superior reduction in dentine hypersensitivity compared to potassium nitrate and a negative control mouthwash after two weeks.
 
-ESCA results.
– (a) CLSM images (fluorescence mode) of dentine surface treated with arginine mouthwash. Image scale 100 mm T 100 mm. (b) CLSM images (fluorescence mode) of dentine surface treated with the negative control mouthwash. Image scale 100 mm T 100 mm.  
-SIMS results.
– NIR spectra of dentine surface treated with Arginine mouthwash.  
Objective: The mode of action of an arginine mouthwash using the Pro-Argin™ Mouthwash Technology, containing 0.8% arginine, PVM/MA copolymer, pyrophosphates and 0.05% sodium fluoride, has been proposed and confirmed as occlusion using a variety of in vitro techniques. Methods: Quantitative and qualitative laboratory techniques were employed to investigate the mode of action of the new arginine mouthwash. Confocal laser scanning microscopy (CSLM) and atomic force microscopy (AFM) investigated a hydrated layer on dentine surface. Electron spectroscopy for chemical analysis (ESCA), secondary ion mass spectroscopy (SIMS) and near-infrared spectroscopy (NIR) provided information about its chemical nature. Results: CLSM was used to observe the formation of a hydrated layer on exposed dentine tubules upon application of the arginine mouthwash. Fluorescence studies confirmed penetration of the hydrated layer in the inner walls of the dentinal tubules. The AFM investigation confirmed the affinity of the arginine mouthwash for the dentine surface, supporting its adhesive nature. NIR showed the deposition of arginine after several mouthwash applications, and ESCA/SIMS detected the presence of phosphate groups and organic acid groups, indicating the deposition of copolymer and pyrophosphates along with arginine. Conclusion: The studies presented in this paper support occlusion of the dentine surface upon the deposition of an arginine-rich layer together with copolymer and phosphate ions from an alcohol-free mouthwash containing 0.8% arginine, PVM/MA copolymer, pyrophosphates and 0.05% sodium fluoride.
 
-Summary of age & gender for subjects in the eight week clinical study.
– Summary of the tactile hypersensitivity scores for subjects who completed the eight-week study. 
Objective: The objective of this eight week, single-center, two-cell, double-blind, and randomized clinical study was to evaluate the dentin hypersensitivity reduction efficacy of a mouthwash using Pro-Argin™ Mouthwash Technology containing 0.8% arginine, PVM/MA copolymer, pyrophosphates, and 0.05% sodium fluoride in an alcohol-free base ("Arginine Mouthwash") compared to an ordinary mouthwash without any active ingredients ("Negative Control"). Methods: Qualifying subjects who presented two hypersensitive teeth with a tactile hypersensitivity score between 10 and 50 g of force, and an air blast hypersensitivity score of 2 or 3 participated in this study and were randomized into one of two treatment groups. Subjects brushed with the toothbrush and fluoride toothpaste provided and then rinsed with 20 mL of their assigned mouthwash for 30s twice daily. Subjects refrained from eating or drinking for 30 min after rinsing. Dentin hypersensitivity assessments, as well as examinations of oral hard and soft tissues, were conducted at the baseline visit and again after two weeks, four weeks and eight weeks of product use. Results: Ninety (90) subjects entered and completed the eight week study. After two weeks, four weeks and eight weeks of product use, subjects in the Arginine Mouthwash group exhibited statistically significant (p<0.05) improvements in mean tactile and air blast hypersensitivity scores as compared to the Negative Control Mouthwash. Conclusion: The results of this study support the conclusion that the Arginine Mouthwash provides a significant reduction in dentin hypersensitivity after eight weeks of product use as compared to a Negative Control mouthwash.
 
The aims of this study were to examine the effect of the use of a mouthwash containing 0.05% cetylpyridinium chloride (CPC) on (1) the composition of the normal oral microbial flora and (2) the establishment of non-oral bacterial species in the mouth. In a double-blind study, 129 subjects used, twice daily for 6 weeks, either a randomly assigned test or placebo mouthwash. At baseline and at the completion of the study, a sample of the oral flora was obtained by asking each subject to "swish" around the mouth for 30 s, 10 ml of distilled water. The numbers of total colony forming units (CFU), facultative bacteria, streptococci, mutans streptococci, lactobacilli, staphylococci, yeasts and enterococci were enumerated after culture on eight non-selective and selective media. After 6 weeks use of either the test or placebo mouthwashes, there were no significant differences (analysis of variance) between the counts (CFU/ml of sample) for any of the microbial taxa. These data indicate that the use of a CPC-containing mouthwash does not alter the composition of the normal oral flora or result in the establishment of non-oral and potentially pathogenic bacteria in the mouth.
 
– Summary of the Air-Blast hypersensitivity scores for subjects who completed the eight-week clinical study. 
-Analysis of Time to Improvementfor Subjects Who Completed the Eight-Week Clinical Study.
Objective: Evaluate the efficacy of three regimens integrating toothpaste, toothbrush and mouthwash in reducing dentine hypersensitivity. Methods: Eight-week single-centre, three-cell, double-blind, randomized study was conducted in the Dominican Republic. Subjects entered one of the three regimens: (1) toothpaste containing 8% arginine and 1450 ppm mono-fluorophosphate, in a calcium carbonate base, a soft-bristle toothbrush followed by a mouthwash containing 0.8% arginine, PVM/MA copolymer, pyrophosphates, and 0.05% sodium fluoride; (2) toothpaste containing 5% potassium nitrate and 1450 ppm sodium fluoride, a soft-bristle toothbrush, followed by a mouthwash containing 0.51% potassium chloride and 230 ppm sodium fluoride; and (3) toothpaste containing 1450 ppm mono-fluorophosphate, a soft-bristle toothbrush followed by a fluoride/arginine free mouthwash. Tactile and Air-Blast dentine hypersensitivity measurements were performed at baseline, two, four, and eight weeks. For treatment group comparisons, ANCOVA and post hoc Tukey's pair-wise (α=0.05) were used. Kaplan-Meier survival analysis was performed to evaluate Time to Treatment Improvement. Results: 120 subjects were enrolled, 118 completed the study. The Tactile hypersensitivity mean scores showed statistically significant improvement at two, four and eight (p ≤ 0.001) weeks in the arginine regime; the potassium regime did not show significant (p ≥ 0.05) improvement. Air-Blast Hypersensitivity scores had a statistically significant decrease at two (p=0.006), four (p=0.006) and eight (p=0.002) weeks in arginine and potassium regimes (p ≤ 0.05). The most effective treatment proved to be arginine (p ≤ 0.05) compared to the potassium regime. Conclusion: Arginine regimen provided the greatest reduction in Tactile and Air-Blast dentine hypersensitivity compared to potassium and negative control regimens; and provides faster dentine hypersensitivity relief than potassium regimen.
 
Administration during root formation of a bisphosphonate, 1-hydroxyethylidene-1,1-bisphosphonate (HEBP), at a dose corresponding to 10 mg P/kg body weight, has been found to interfere with the formation of acellular cementum in rats. The purpose of this study was to measure the force required to extract a tooth lacking normal acellular cementum, and to correlate this force and the ultimate periodontal strength with the morphology of the periodontal tissues at different time intervals after single or multiple injections of HEBP. A single injection of HEBP given during root formation inhibited the formation of acellular cementum and resulted in a temporary reduction of the extraction force and the ultimate tensile strength. Ninety days after the injection of HEBP, both parameters were the same as in the controls. The increase in extraction force and ultimate tensile strength was associated with the onset of occlusal contact of the teeth. The organization of periodontal ligaments was improved after the teeth reached the occlusal level. After daily injections of HEBP for 3 days, there was a permanent reduction in root length and dento-alveolar ankylosis developed in the furcation area. (1) A single or three injections of HEBP changed the formation of acellular cementum to that of an atypical hyperplastic cementum which increased the resorption risk at this site. (2) The ultimate tensile strength was markedly reduced in teeth lacking acellular cementum.
 
Geometry stabilizing equipment and imaging equipment. 
Disposition of children throughout the study.
Objetivo: Comparar la eficacia para detener y revertir las lesiones de caries coronal en estadio temprano en niños, de un nuevo dentífrico que contiene arginina al 1.5%, un compuesto de calcio insoluble y 1450 ppm de fluoruro con un dentífrico control positivo con 1450 ppm de fluoruro, mediante el uso de Fluorescencia Cuantitativa Inducida por Luz (QLF). Diseño del Estudio: 331 niños de Chiang Mai, Tailandia, de 7 a 14 años de edad, con una o más lesiones visibles de caries en esmalte en estadio temprano en los dientes anteriores superiores, completaron el estudio. El nuevo dentífrico contenía arginina al 1.5%, un compuesto de calcio insoluble y 1450 ppm de fluoruro como monofluorofosfato de sodio; el control positivo tenía sólo 1450 ppm de fluoruro. Los sujetos se cepillaron dos veces al día en casa y una vez adicional en días escolares bajo la supervisión de un profesor. Se tomaron imágenes digitales de los seis dientes anteriores superiores al inicio, a los 3 y a los 6 meses usando un aparato hecho a la medida para lograr la obtención reproducible de los datos de Fluorescencia Cuantitativa Inducida por Luz. Resultados: En el examen de los 3 meses, el ΔQ (que representa el volumen de la lesión) para el grupo de estudio, disminuyó de una media de 28.62 al inicio hasta 20.53 mm2% y en el grupo control positivo hasta 23.38 mm2%. La diferencia entre los grupos no fue estadísticamente significativa (p=0.055). En el examen de los 6 meses, el ΔQ disminuyó en el grupo de estudio a 15.85 mm2% y en el grupo control positivo a 20.35 mm2%. La diferencia entre los grupos fue estadísticamente significativa (p<0.001). Conclusión: Un nuevo dentífrico que contiene arginina al 1.5%, un compuesto de calcio insoluble y 1450 ppm de fluoruro como monofluorofosfato de sodio, tuvo una eficacia significativamente superior desde el punto de vista estadístico para detener y revertir las lesiones coronales activas de caries en niños que el cepillado con un dentífrico control positivo que contiene fluoruro solamente.
 
Objetivo: este artículo discute brevemente la prevalencia de caries, la naturaleza multifactorial de su etiología, el riesgo de caries y el papel y eficacia del fluoruro. Resalta también la investigación sobre el metabolismo bacteriano, que ha aportado conocimientos sobre la defensa natural oral contra la caries y la base para el desarrollo de una nueva tecnología para la prevención diaria y el tratamiento de la caries. Por último, se resume la evidencia que respalda que la tecnología complementa y mejora la eficacia anti-caries de la crema dental con fluoruro. Conclusiones: los datos globales muestran que a pesar de la exitosa introducción del fluoruro, la caries dental es una enfermedad prevalente. La experiencia de caries depende del balance entre el consumo de azúcares, la higiene oral y el uso del fluoruro. Hay tres conceptos científicos que son fundamentales en las nuevas mediciones para detectar, tratar y monitorear la caries: (1) la caries dental es un proceso dinámico, (2) la caries dental es un proceso continuo de etapas que van desde reversible (pre-clínica) hasta irreversible (lesiones clínicamente detectables), y (3) el proceso de la caries es un balance de factores patológicos y protectores que pueden modularse para el manejo de la caries. El fluoruro funciona como factor protector al detener y revertir el proceso de la caries, pero el fluoruro no previene los factores patológicos que inician el proceso. Se ha identificado una tecnología novedosa, basada en arginina y un compuesto insoluble de calcio, que está dirigida a la placa dental para prevenir la iniciación del proceso de caries al reducir los factores patológicos. Como los mecanismos de acción de la arginina y el fluoruro son altamente complementarios, se ha desarrollado un nuevo dentífrico que combina la arginina y el fluoruro, y se ha probado clínicamente que brinda una prevención superior contra la caries.
 
The aim of this study was to present an 11-year assessment of direct resin composite inlays/onlays. One-hundred Class II direct resin composite inlays and 34 direct resin composite restorations were placed in 40 patients. The restorations were evaluated clinically, according to modified USPHS criteria, annually over a 11-year period. Of the 96 inlays/onlays and 33 direct restorations evaluated at 11 years, 17. 7% in the inlay/onlay group and 27.3% in the direct restorations group were assessed as unacceptable. The differences in longevity were not statistically significant. The main reasons for failure for the inlays/onlays and direct restorations were fracture (8.3 and 12. 1%, respectively), occlusal wear in contact areas (4.2 and 6.1%, respectively) and secondary caries (4.2 and 9.1%, respectively). Eight of the non-acceptable inlays/onlays and five of the direct restorations were replaced, while the other ones were repaired with resin composite. Unacceptable wear was observed in occlusal contact areas of six restorations, in patients who were severe bruxers. For the other restorations occlusal wear was not found to be a clinical problem and no difference was observed between the inlays/onlays and direct composite restorations. The marginal adaptation of the inlays/onlays was still good at the end of the study. Ditching was only observed in a few inlays. A higher failure rate was observed in molar teeth than in premolar teeth. Good durability was observed for the direct resin composite inlay/onlay technique. Excellent marginal adaptation and low frequency of secondary caries in patients with high caries risk were shown. No apparent improvement of mechanical properties was obtained by the secondary heat treatment of the inlays. Also, the difference in failure rate between the resin composite direct technique and the inlay technique was not large, indicating that the more time-consuming and expensive inlay technique may not be justified. The direct inlay/onlay technique is recommended to be used in Class II cavities of high caries risk patients with cervical marginal placed in dentin.
 
This paper describes the database used to assess the survival of indirect restorations and presents general data on survival of these restorations. Data, based on the complete attendance and treatment history, over the 11 years from 1991 to 2001, of a statistically representative sample of 23,165 General Dental Services' (GDS) patients in England and Wales, all of whom received at least one indirect restoration during the observation period, have been analysed. The patients on the database received a total of 36,397 courses of treatment, and there were 52,481 indirect restorations placed. The method of analysis involved the estimation of the probability that the patient will eventually return, given an interval without attending, by analysing the observed patterns of re-attendance. This estimated probability of re-attendance was then used to modify the standard Kaplan-Meier procedure to produce realistic estimates of the hazard of re-intervention. Overall, 75% of indirect restorations remained without re-intervention after 5 years, and 61% after 10. Crowns outperformed other types of indirect restoration. Multi-surface metal inlays, by contrast, had a median interval to re-intervention of less than 8 years. The times to re-intervention for different types of indirect restoration have been successfully estimated and crowns shown to outperform veneers and inlays.
 
This paper describes the analytical approach used to extract empirical distributions of the interval from the date of placement of a direct restoration to the date when the next intervention took place on the same tooth, that is, an estimate of restoration survival. Data, based on the complete attendance and treatment history, over the eleven years from 1991 to 2001, of a statistically representative sample of 82,537 General Dental Services' patients in England and Wales, all of whom received at least one directly placed restoration during the observation period, have been analysed. The patients on the database received a total of 719,009 courses of treatment, and there were 503,965 occasions when a tooth was directly restored. The method of analysis involved, first, the estimation of the probability that the patient will eventually return, given an interval without attending, by analysing the observed patterns of re-attendance. This estimated probability of re-attendance was then used to modify the standard Kaplan-Meier procedure to produce realistic estimates of the hazard of re-intervention. The results demonstrate that the newly developed methodology has produced robust estimates of the distribution of survival intervals to next intervention on the same tooth. Regarding attendance patterns, re-attendance probability varies with length of interval since last attendance. There is also a strong association with patient age. The older the patient, the more likely it is that a gap in attendance is indicative that the patient will never return. The detailed cumulative survival curve over eleven years has been plotted and forty-seven per cent of restorations, overall, survived without re-intervention for at least ten years. The entire analysis was then successfully replicated on a second, independently selected, sample of attendance and treatment records, confirming the ten-year survival estimate. This newly developed methodology has produced robust estimates of the distribution of survival intervals to next intervention on the same tooth. Patient re-attendance probability varies with length of interval since last attendance and with patient age. The ten-year overall survival rate to next intervention on the same tooth for direct restorations placed within the GDS in England and Wales is circa 47%.
 
The effect of social class on the dental disease status of a group of 11–12-year-old schoolchildren in South Wales is presented. There were a number of differences between the social classes for the DMFT, DMFS and DFS indices, with social class I having significantly less caries experience than the others. These differences, however, were largely confined to the boys. There appeared to be no significant difference in reported toothbrushing frequency between the social classes but the children from the lower social classes admitted spending significantly more on sweets per week. The plaque and gingival bleeding scores showed an overall trend to increase from social class I through to social class V. The girls, in particular, showed progressively increasing and significantly different mean plaque and gingivitis scores.
 
An analysis of factors influencing the initiation of carious lesions on specific tooth surfaces over a 4-year period in children between the ages of 11-12 years and 15-16 years is presented. Approximately 1000 children, resident in the County of South Glamorgan, Wales, were assessed for caries status and oral cleanliness in 1980 when aged 11-12 years and again in 1984 when aged 15-16 years. On both occasions, the children completed detailed questionnaires on dental health-related topics. Surfaces which were sound when the children were 11-12 years were identified and subsequently awarded a score of zero if they remained sound at 15-16 years or a score of one if they had developed carious lesions or had been filled. For each child, a mean mouth caries initiation score was computed for specific groups of surfaces, namely pit and fissure surfaces in posterior teeth, approximal surfaces in posterior teeth, buccal and lingual smooth surfaces of all teeth and approximal surfaces of anterior teeth. One-way analysis of variance and multiple regression techniques revealed that a number of factors had a significant influence on the initiation of caries. The factors and their level of significance varied between the surfaces. However, relatively little (less than 6 per cent) of the total variance in caries initiation score could be explained by the identified factors. Overall, more lesions developed in pit and fissure surfaces in posterior teeth than in the other surfaces included in the analyses.
 
Attempts have been made to develop diagnostic methods which enable an early diagnosis of occlusal lesions which are not detectable by visual inspection. The aim of this study was to compare the performance of visual inspection focused on finding signs of fissure decalcification and discoloration, visual inspection upon fibre-optic transillumination (FOTI), and electrical conductance measurements (ECMs) in predicting the onset of occlusal caries in 6- and 11-year-old children. Fifty children aged 5-7 and 11-15 years, having first or second permanent molar teeth that were not exposed to the oral environment for more than half a year, participated in the study. Following baseline data recording, the diagnostic measurements were repeated six times at 6-month intervals over a period of 2.5 years. Data were collected at predefined sites in the fissures. During the study, 220 of the 652 sites, i.e. 75 of 197 molars in 31 of the 50 children were judged to require a sealant or a sealant restoration. Two examiners jointly decided on the decay status at the sites. Survival plots showed that ECMs were superior to FOTI and fissure discoloration in predicting the onset of occlusal caries, although the differences were small. ECM is a better predictor of occlusal caries than fissure discoloration and FOTI, although the differences among the performance of the three methods in this study were very small. A cost-effective analysis is envisaged to obtain insight into the practical value of ECMs in the prediction of occlusal caries and, thus, into the effectiveness of sealant application.
 
Four hundred and ninety-four 11- and 12-year-olds were examined for caries. The aim was to re-examine the same children six times at annual intervals. Finally 41 per cent of the original population were seen. During the study the mean DMF value increased from 5·5 to 13·3 teeth, the proportion of filled to DMF teeth increased from 58 to 72 per cent. The new DMF teeth were mainly second permanent molar and premolar teeth.
 
An analysis of factors influencing the caries experience of adolescents in South Wales is presented. Approximately 1000 children were assessed for caries status and oral cleanliness in 1980 when aged 11-12 years and again in 1984 when aged 15-16 years. In addition, on both occasions, the children completed detailed questionnaires on dental health-related topics. When aged 11-12 years, the observed mean DMFT, DMFS and DFS scores of the children were 4.0, 6.7 and 5.5 respectively. The corresponding scores at age 15-16 years were 6.5, 11.8 and 10.2. A preliminary analysis using conventional multiple regression techniques revealed that a number of factors had a significant influence on the caries experience of the children. The significance of the factors depended on the sex of the population subgroup, the age of the children and the particular caries index studied. However, at both ages the factors of most significance were the number of erupted teeth, total mean plaque score and the reported amount of money spent on sweets per week. A further evaluation using analysis of covariance with the number of erupted teeth and surfaces as the covariates confirmed the significant influence of the total mean plaque score and amount of money spent on sweets. In addition, both analyses indicated that toothbrushing frequency and social class had a significant influence on the caries experience of boys.
 
The lesions most commonly found at the apices of non-vital teeth are the periapical granuloma and radicular cyst. The treatment and prognosis may differ according to the lesion present. Previous studies to determine the diagnostic features and incidence of these lesions have failed to reach a consensus view. A study of over 1000 endodontic surgery procedures was therefore carried out.Of 1108 lesions assessed, 186 (16·8 per cent) were shown histopathologically to be cystic. Of 163 maxillary cysts, 95 were associated with lateral incisors. The highest incidence of cysts and granulomas was noted in the fourth decade for both male and female patients. The incidence in both cases was not significantly different between the sexes. In addition to radicular cysts, one keratocyst and one globulomaxillary cyst were determined histopathologically. The accuracy of the authors' clinical diagnosis was comparable to that of previous workers.
 
Resin composite sealants are retained longer than low-viscosity glass-ionomer sealants. Nevertheless, a systematic review showed that there is no evidence that resin composite sealants are superior to low-viscosity glass-ionomers in preventing dentine carious lesion development. This case study aimed to investigate reasons for this. 4 teeth were sealed with 2 brands of high-viscosity glass-ionomer according to the ART technique in 2 children aged 10 and 11.5 years, having a low caries-risk status, and followed clinically for between 8 and 13 years. At the final year, impressions were taken for SEM images that were assessed by two evaluators. Pits and fissures that were clinically diagnosed as free of sealant material appeared to contain remnants of high-viscosity glass-ionomer sealant material in the deeper parts of pits and fissures, on SEM images of 3 teeth. This study confirms the likelihood that remnants of high-viscosity glass-ionomer sealant material are retained and block the deeper parts of pits and fissures even after the sealant appears to have disappeared clinically, exercising their carious lesion preventive effect.
 
It is well understood that the application of a self-etching primer enhances the bonding of the resin to the tooth. In this study, the demineralisation aspects by the Mega Bond Primer (MB) or the UniFil Bond Primer (UB) on the tooth were investigated by using liquid-state and solid-state 13C NMR techniques. The addition of hydroxyapatite or dentine to MB and the addition of dentine to UB resulted in the decrease in the peak intensity of the 13C NMR peaks attributed to the methacryloxy decyl phosphoric acid, MDP in the MB or 4-methacryloyloxy ethoxy carbonylphthalic acid, 4-MET in the UB. This decrease was because the MDP or 4-MET demineralised the tooth and the calcium salts produced from the MDP or 4-MET were precipitated from the MB or UB solution. The NMR technique is very powerful in evaluating the demineralisation aspects of the tooth by a self-etching primer. However, the calcium salts produced by the MDP or 4-MET on the tooth surface would not facilitate retention in bonding, since these calcium salts were merely deposited on to the surface of the tooth.
 
To evaluate the effectiveness of Opalescence PF 10% just after treatment, at 6-month follow-up and at a 14-month follow-up period. Opalescence PF 10% was applied nightly for 14 days. The color of teeth 11 and 21 of 17 subjects were measured with a spectrophotometer (L*; a*; b*) before treatment, just after treatment (14 days), after 6 months and after 14 months. Subjects were instructed to take note of any tooth sensitivity. For all three components (L*, a* and b*) statistical significant differences (p<0.05) in the values between base-line, after treatment (14 days later), after 6 months and after 14 months were found (Wilcoxon Signed Rank Sum Test). The decrease in L* was about 20% after 6 months and about 50% after 14 months. The a* value decreased approximately 14% after 6 months but was worse after 14 months than at the beginning. The b* value decreased the least with about 9% after 6 months and about 8% after 14 months. The decrease in DeltaE(ab)(*) was approximately 20% after 14 months. Less than 20% of the subjects experienced mild tooth sensitivity just after treatment. Significantly whiter teeth were found after treatment as well as after a 6-month follow-up period. The whiteness/brightness (L*) decreased with approximately 50% after 14 months and the a* value with approximately 50% after 7 months, while the yellowness (b* value) remained even after 14 months. The product is an effective tooth whitener resulting in only low tooth sensitivity. Re-bleaching could be done at about 14 months.
 
Objectives: This study aimed to validate the Quality of Life with Implant-Prostheses (QoLIP-10) questionnaire for assessing the impact of screwed implant-supported rehabilitations on oral health-related quality of life (OHRQoL). Methods: 131 patients wearing screw-retained implant restorations were assigned to the following groups: Group 1 (HP; n=50): fixed-detachable hybrid prostheses (control), Group 2 (S-PD; n=43): metal-ceramic screwed partial dentures, and Group 3 (S-CD; n=38): metal-ceramic screwed complete dentures. Impacts on OHRQoL were evaluated using the QoLIP-10 and Oral Health Impact Profile (OHIP-14sp) scales. Data on global oral satisfaction, socio-demographics, health-behaviours, and prosthetics were gathered. Reliability and validity of the QoLIP-10 were investigated for screwed prosthesis wearers. The Spearman's rank test was applied to determine the correlation between both indices. Descriptive and non-parametric probes were run to evaluate the influence of the study variables on OHRQoL. Results: The QoLIP-10 confirmed its psychometric capacity for screwed prosthesis wearers. Both tests were inversely correlated. HP wearers reported the worst dental-facial aesthetics, performance, and functional limitation outcomes. Gender, education level, complaints about the mouth, perception of treatment needs, and prosthetic status modulated the OHRQoL. Conclusions: Screwed implants restorations provide better OHRQoL than do fixed-detachable hybrid prostheses.
 
The corrosion behaviour of Ti-15Mo alloy in 0.15M NaCl solution containing varying concentrations of fluoride ions (190, 570, 1140 and 9500 ppm) is evaluated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and chronoamperometric/current-time transient (CTT) studies to ascertain its suitability for dental implant applications. The study reveals that there is a strong dependence of the corrosion resistance of Ti-15Mo alloy on the concentration of fluoride ions in the electrolyte medium. Increase in fluoride ion concentration from 0 to 9500 ppm shifts the corrosion potential (E(corr)) from -275 to -457 mV vs. SCE, increases the corrosion current density (i(corr)) from 0.31 to 2.30 microA/cm(2), the passive current density (i(pass)) from 0.07 to 7.32 mA/cm(2) and the double-layer capacitance (C(dl)) from 9.63 x 10(-5) to 1.79 x 10(-4)F and reduces the charge transfer resistance (R(ct)) from 6.58 x 10(4) to 6.64 x 10(3)Omega cm(2). In spite of the active dissolution, the Ti-15Mo alloy exhibit passivity at anodic potentials at all concentrations of the fluoride ions studied. In dental implants since the exposure of the alloy will be limited only to its 'neck', the amount of Mo ions released from Ti-15Mo alloy is not likely to have an adverse and hence, in terms of biocompatibility this alloy seems to be acceptable for dental implant applications. The results of the study suggest that Ti-15Mo alloy can be a suitable alternative for dental implant applications.
 
The position of the gingival margin, as indicated by clinical crown height, was determined in the permanent teeth of 237 Caucasian children aged between 6 and 16 years. With increasing age, a shift of the gingival margin towards the cementoenamel junction was observed in all the teeth with the exception of the lower second molar. This development levelled off after the age of 12 in the case of the mandibular central incisors, canines, second premolars and first molars. In the remaining teeth the gingival margin continued to recede until 16 years, the oldest group in the study
 
The relationship between loss of first permanent molar teeth and the prevalence of caries and restorations in the surfaces of adjacent teeth was assessed in a group of 793 children, aged 15–16 years old. The data obtained from the children was divided into two subgroups. Group 1 comprised those arches in which the first permanent molar had been retained, and Group 2 contained those arches in which the first permanent molar had been extracted before the age of 11–12 years. The disease status of the mesial and occlusal surfaces of second molars and the distal and occlusal surfaces of second premolars was examined visually and radiographically in both groups. Arches with missing first molars had significantly fewer decayed and filled approximal surfaces but significantly more decayed and filled occlusal surfaces in the adjacent second molar and premolar teeth than those arches which had not lost the first molar. The implications of these findings are discussed.
 
The aim of this long-term follow-up was to collect up to 17-year survival data of different metal post-and-core restorations with a covering crown. At initiation of the study, a controlled clinical trial, single tooth was provided with an artificial covering crown, by 18 operators. Restorations under investigation were the post-and-core restorations: cast post-and-core restorations, prefabricated metal post and resin composite core restorations, and post-free all-composite core restorations. Before treatment allocation, the recipient tooth was categorized according to the expected dentin height after tooth preparation. A tooth was assessed to have "substantial dentin height" (Trial 1) or "minimal dentin height" (Trial 2). The study sample consisted of 257 patients that received 307 core restorations. The performance of the restorations was based on data collected from the files of the current dentists monitoring the oral health of the patients. The survival probability was analyzed at different levels: on the restoration level (S(R)), and on the level of the tooth carrying the restoration (S(T)). Kaplan Meier analyses were used to compare survival probabilities. "Type of post-and-core restoration" showed no influence on the survival probability (at both levels) in both trials (P-value>0.05). The 17-year survival rates at restoration level varied from 71% to 80%, and at tooth level from 83% to 92%. The results of this study showed no difference in survival probabilities among different core restorations under a covering crown of endodontically treated teeth. The preservation of substantial remaining coronal tooth structure seems to be critical to the long-term survival of endodontically treated crowned teeth.
 
Since an increasing number of composite restorations in posterior teeth are placed as a routine, this study was conducted to evaluate long-term survival of these restorations placed in general practice. Patients from a private dental office that received restorations in posterior teeth between 1987 and 1988 with P-50 (3M) or Herculite XR (Kerr) resin composites were selected and invited to participate. Restorations were placed under rubber dam isolation. Dentine walls were covered with glass ionomer cement, and composites were placed according to manufacturer's instructions. Thirty-eight patients agreed to participate and signed an informed consent prior to the evaluation. Two calibrated operators worked independently in the evaluation, using modified USPHS criteria. Survival of restorations or subsets of restorations grouped on the basis of variables (material, tooth, cavity type and size) was determined using Kaplan-Meier survival curves. Ninety-eight failures were recorded among the 282 restorations providing a crude estimate of 34.8% failures. The survival rate was not significant for material (p=0.92) but was significant between tooth (lower premolars and lower molars, p<0.0001), cavity type (p<0.001) and size (p<0.001). The majority of restorations exhibited A or B scores for the evaluated criteria. The main failure cause was fracture of both composites. The clinical performance of posterior resin composite restorations evaluated was acceptable after 17-year evaluation. However, the probability of failure of resin composite restorations in molars, Class II, and large restorations is higher.
 
This split-mouth, double-blind, randomized controlled study evaluated the clinical performance of composite restorations in Class I beveled margin cavity preparations in primary molars. A total of 94 Class I cavity preparations were performed in the carious primary molars of 32 children aged 4-10 years. Two cavity designs were used: conventional conservative preparation (G1) and modified preparation with cavosurface bevel (G2). All teeth were restored using TPH Spectrumtrade mark. The restorations were evaluated by two calibrated investigators at baseline, 6, 12 and 18 months using slight modified USPH criteria. The visible plaque index and fiber optic transilumination (FOTI) were also used. The data were statistically evaluated using Wilcoxon and Friedman tests (p<0.05). The rank correlations between secondary caries, visible plaque index and FOTI were obtained using Pearson correlation (p<0.01). Of the 94 restorations performed and evaluated at baseline, 76 restorations were available after 18 months. Seventy-three restorations were considered as clinical success, 10 were censored for drop out reasons and 5 were lost by natural exfoliation. Four restorations failed by secondary caries and two failed by marginal adaptation discrepancies. For all evaluation there was difference between the baseline, 6, 12 and 18 months (p<0.05) but there were no statistically significant difference in G1 and G2 for any criteria evaluated (p>0.05) at any period of the study. The visible plaque index was correlated to secondary caries. Bevel cavity design preparations did not improve the success of composite restorations in primary molars over 18 months.
 
The associations of wear in dentine and those explanatory factors with p values less than 0.05. All other factors were not significantly related. 
The association of acidic foods and drinks to the development of erosive tooth wear was investigated in a single cohort of adults aged 18-30 years. A tooth wear index was recorded on 1010 participant's who had a mean age of 21.9 years (SD 0.1) and of which 70% were female and 30% males. Participant's completed a previously validated questionnaire containing 50 questions about current and historical dietary habits. Data were analysed at the tooth level using odds ratio. Tooth wear was statistically significantly associated to acidic foods and drinks with high titratable acidity and dietary habits, including drinking from a glass and holding drinks, (OR 5 and 6.5 respectively). A history of heartburn was statistically significantly associated to palatal dentine exposure (p≤0.05 and OR 7.6). In this sample of adults, tooth wear was associated to a number of acidic dietary products and drinking habits.
 
To measure the added value of panoramic radiography in new dentate patients attending for routine treatment. Thirty-seven general dental practitioners using panoramic radiographs routinely were recruited. Twenty dentate patients were identified prospectively by each participating dentist if they were new to the practice, attending for an examination and requesting any treatment deemed necessary. A panoramic radiograph was taken with appropriate intraoral radiographs in line with national guidelines. Each dentist completed a radiological report for the panoramic radiograph only and these 20 reports were forwarded to the researchers along with the 20 panoramic radiographs, their accompanying bitewing and periapical radiographs and twenty completed clinical assessment sheets. 740 panoramic, 1418 bitewing and 325 periapical radiographs were assessed by the researchers. Only 32 panoramic films provided any additional diagnostic value when compared to intraoral films when guidelines had been observed resulting from the poor technical and processing quality of the accompanying intraoral films. Assessment of the number of caries and periapical lesions and the degree of periodontal bone loss from the intraoral films provided a greater diagnostic yield at the p<0.001 level of significance. The research found that dentists underestimated the number of caries lesions present and level of periodontal bone loss when compared to the researchers but overestimated the presence of periapical pathology, at the level of significance at p<0.001. The study found that there was no support for the use of panoramic radiographs in routine screening as there was no net diagnostic benefit to the patient.
 
The aim of this study was to compare the effect on oral soft tissue of a self-applied tooth whitening gel containing 6% hydrogen peroxide (Xtra White) with a marketed paint-on whitening gel containing 18% carbamide peroxide (Colgate Simply White) after 2-weeks of using products four times daily. A 2-week, examiner-blind, stratified, parallel design clinical trial was conducted. Twenty subjects were divided into two groups, balanced according to age and gender. Subjects followed a 2-week, twice-daily regimen of brushing with standard fluoride toothpaste and applied gel product to facial aspects of six upper and six lower incisors/canines, twice in succession with 30 min between applications. Soft tissue examinations were performed on Day 1, before the first application of the test products, and on Day 2, 5, 8 and 15. During the 2-week treatment period, twelve adverse reactions were recorded as potentially attributable to the study products, evenly split between the two test groups. All reports were mild in symptoms and resolved without the need of medical intervention. None of the subjects experiencing an adverse event requested to be withdrawn from the study. Under the exaggerated use conditions of this test, there was no evidence to suggest that either of the whitening gels produced irritation that was building or developing during the course of the study. It is concluded that both products are safe for their intended use.
 
A case of bilateral tooth rotation through 180 involving the maxillary second premolars in a 30-year-old male patient is presented.
 
The objective of this study was to investigate the relationship between age, gender and clinical crown length using a longitudinal study design. Four hundred and fifty-six sets of study models initially obtained for a large prospective longitudinal cohort study of orthodontic needs were examined. Each set of models corresponded to subjects at three different ages: 11-12, 14-15 and 18-19years old. The clinical crown height of the maxillary right central incisor (11), maxillary right canine (13), maxillary left lateral incisor (22) and mandibular left central incisor (31) was measured from gingival crest to the incisal edge using digital calipers. Analysis revealed a significant (p<0.0001) age effect on crown length for all four teeth investigated. A significant gender effect was found in relation to the maxillary right canine, maxillary right central incisor and maxillary left lateral incisor. Pairwise comparisons of the means for each age group for the maxillary right canine, maxillary right central incisor and maxillary left lateral incisor revealed significant (p<0. 0001) increases in clinical crown length between each assessment period. The findings of the present study indicate that, the process of passive eruption, resulting in increased clinical crown length appears to continue throughout the teenage years. This finding is considered to be of importance to the clinician making treatment decisions for teenagers and young adults requiring treatment in the anterior segments of the mouth.
 
The aim of this study is to characterise a range of model and commercially available glasses used to form glass (ionomer) polyalkenoate cements. A range of model fluoro-alumino-silicate glasses that form the basis of glass (ionomer) polyalkenoate cements and five commercial glasses have been characterised by 29Si, 27Al, 31P and 19F Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR). The 29Si spectra indicate a predominantly Q33Al and Q44Al structure where the Q33Al species represents a silicon with one non-bridging oxygen and three Si-O-Al linkages and the Q44Al species a silicon with four Si-O-Al bonds. Aluminium was found in predominantly four coordinate sites, but glasses with high fluorine contents showed an increasing proportion of five and six coordinate aluminium. In phosphate containing glasses the phosphorus was present as Al-O-PO3(2-) type species indicating local charge compensation of Al3+ and P5+ in the glass structure. 19F MAS-NMR indicated the presence of F-Ca(n), Al-F-Ca(n), F-Sr(n), Al-F-Sr(n) and Al-F-Na(n) species where F-M(n) indicates a fluorine surrounded by n next nearest neighbour cations and Al-F-M(n) represents a fluorine bonded to aluminium with the metal, M in close proximity charge balancing the tetrahedral AlO3F species. The proportion of Al-F-M(n) species increased with increasing fluorine content of the glass and lower non-bridging oxygen contents. There was no evidence of Si-F bonds in any of the glasses. The local structure of the phosphate containing glasses with regard to fluorine, calcium, strontium and phosphate is similar to that of fluorapatite the mineral phase of tooth. This may explain the ease with which these glasses crystallize to fluorapatites and the recently observed mineralization of glass polyalkenoate cements found in vivo.
 
A survey was conducted to assess whether there were any differences in the clinical methods employed in constructing full dentures by dentists and final year dental students.Students at twelve British dental schools and dentists who graduated between 1956 and 1970 were surveyed. Students took about hours spaced over 5–6 visits whilst dentists took 68·4 minutes over 4 appointments to complete a set of dentures. Over 90 per cent of dentists did a preliminary examination, one impression, adjustment of bite, try-in and final fit for 90 per cent or more of their full denture cases. Only 47·8 per cent generally took preliminary impressions and 30·4 per cent usually did border moulding. Facebows and gothic arch tracings were not frequently carried out by dentists. A small number of dentists appeared to allow their technicians to do procedures in the mouth. Students generally did all steps in denture construction and had to do the laboratory work in at least one case. They had to complete 3 cases at one dental school and as many as 20 at another.Twenty-two per cent of dentists said that of all their undergraduate subjects, they were best prepared in full denture construction by their dental undergraduate course; less than 5 per cent of students had that opinion. The majority of dentists and students would like the same amount of instruction in full dentures (75 per cent of dentists and 70 per cent of students); only 6·6 per cent of dentists wanted less teaching in the subject.There were differences between the time taken and number of stages employed by students and practitioners. If teachers are convinced of the usefulness of the procedures that they teach they should teach them with greater conviction.
 
This paper reviews the work on dental materials published in 1975. The main areas reviewed are dental amalgam, casting alloys, polymeric materials including composites and fissure sealants, impression materials, ceramics, dental cements of all types, dental implants and dental biomechanics.
 
This paper, which is presented in two parts, reviews the work on dental materials published in 1977. Included in Part I were sections on amalgam, casting alloys, denture base polymers, composite filling materials, tissue conditioners and soft lining materials and fissure sealants. A review of the literature relating to impression materials, dental ceramics, model and die materials, cements, dental implants and dental biomechanics is presented in Part II.
 
This paper, which is presented in two parts, reviews the work on dental materials published in 1978. Included in Part I were sections on cements, amalgam, composite filling materials, endodontic materials and fissure sealants. A review of the literature relating to biomechanics, impression materials, model, die and mould materials, waxes, cast and wrought alloys, acrylic resins, tissue conditioners and soft lining materials, ceramics, implants and corrosion is presented in Part II.
 
This paper, which is presented in two parts, reviews the work on dental materials published in 1979. Included in Part II are sections on impression materials, model, die and investment materials, waxes, acrylic resins, denture base polymers, soft lining materials and tissue conditioners, cast and wrought dental alloys, ceramics, implants and, finally, corrosion. Part I included sections on dental biomechanics, fissure sealants, cements, amalgam, composite filling materials, endodontic materials and microleakage.
 
This paper, which is presented in two parts, reviews the work on dental materials published in 1979. Included in Part I are sections on dental biomechanics, fissure sealants, cements, amalgam, composite filling materials, endodontic materials and, for the first time, microleakage. Part II will include sections on impression materials, model, die and investment materials, waxes, acrylic resins, denture base polymers, soft lining materials and tissue conditioners, cast and' wrought dental alloys, ceramics, implants and, finally, corrosion.
 
This paper, which is presented in two parts, reviews the work on dental materials published in 1980 Included in Part 2 are sections on dental biomechanics, amalgam, corrosion, casting alloys, soldering, electroplating, magnetic materials, metals and alloys for orthodontic use. Part 1 included sections on composite filling materials, fissure sealants, microleakage, dental ceramics, acrylic resins, impression materials, dental cements, adhesion, endodontic materials, model, die, mould and investment materials.
 
This review, which is presented in two parts, covers the work on dental materials published in 1981. Included in Part 1 are sections on dental biomechanics, composite filling materials, acrylic resins, microleakage, and dental cements. Part 2 will include sections on dental ceramics, endodontic materials, fissure sealants, dental amalgam, casting alloys, impression materials and model and die materials.
 
This is the second part of the report on the 1982 literature on dental materials. Included are reviews on impression, cast, die and mould materials, polymeric prosthetic materials, aspects of adhesion, fissure sealants, composite resins, cements and endodontic materials.
 
This report, which is to be presented in two parts, reviews published papers on dental materials, based on literature for 1982. In this part the following topics are considered: metals, including dental amalgam and casting and wrought alloys; ceramics, implants and aspects of dental biomechanics.
 
Top-cited authors
Megan Addy
  • University of Chester
Andrew Joiner
  • Retired formerly Unilever Oral Care
Paul Lambrechts
Frank Tay
  • Augusta University
Bart Van Meerbeek