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PubMed2002

Dentine hypersensitivity in subjects recruited for clinical trials: clinical evaluation, prevalence and intra-oral distribution.

Relatively few studies have reported on the frequency, distribution and severity of dentine hypersensitivity (DH) in subjects recruited for clinical trials of desensitizing agents. Potential subjects (n= 48 M, 81 F, mean age 35.1 years) for inclusion into such a study were screened to determine the extent of the problem. 117 subjects (41 M, 76 F) mean age 24.9 years were clinically examined. Evaluation by questionnaire indicated that the prevalence of DH was proportionately higher in the 20-29.9 years (34.9%), and 30-39.9 years groups (33.3%), respectively. Sensitivity to cold was the main presenting symptom. Tactile (probe) and cold air (dental air syringe) stimuli were used to clinically evaluate DH. Of the teeth eligible for evaluation 1561/3136 (49.8%) responded to either one or both of the test stimuli; 274/3136 (8.7%) responded to tactile only stimulation, 779/3136 (24.8%) to thermal only stimulation and 508/3136 (16.2%) to both tactile and thermal stimulation. Of those teeth responding to the stimuli, 477 (30.6%) were premolars, 437 (28%) incisors, 415 (26.8%) molars and 232 (14.9%) canines. The results agree with those of previously reported studies in that DH is most frequently observed on premolars and that proportionately more teeth are sensitive to evaporative than to tactile stimulation. Furthermore it would appear from the results of the study that tactile is less effective than thermal/evaporative stimulation in the evaluation of DH.

Adult↗

PubMed2002

The effect of variation in occlusal loading on the development of abfraction lesions: a finite element study.

Abfraction or non-carious cervical tooth loss is poorly understood and one factor thought to contribute to the development of these lesions is the effect of occlusal loading. The aim of this study was to examine the effect that varying the position of an occlusal load would have on the stress contour in the cervical region of a lower second premolar using a two-dimensional plane strain finite element model. A 500 N load was applied vertically to either of the cusp tips or in various positions along the cuspal inclines. It was found that loads applied to the inner aspects of the buccal or the lingual cuspal inclines produced maximum principal stress values of up to 358 MPa that exceed the known failure stresses for enamel.

Bite Force↗

PubMed2002

Three-year clinical evaluation of a resin modified glass-ionomer cement and a composite resin in non-carious class V lesions.

The purpose of this study was a 3-year clinical evaluation of a resin modified glass-ionomer and a composite resin restorative material in non-carious class V lesions. In 24 patients 98 non-carious class V lesions were restored with either a resin modified glass-ionomer (Vitremer), or a composite resin restoration (Z100). The restorations were clinically evaluated after 6, 12, 24 and 36 months with the US Public Health Service criteria. At 3 years, 88 teeth of 21 patients were evaluated. All restorations were rated clinically acceptable for colour match, marginal discoloration, marginal adaptation and anatomical form. Restoration retention of both groups was high without any statistically significant difference. However, Vitremer restorations showed a lower incidence of Alfa scores for colour match and marginal discoloration than Z100 restorations (P < 0.05).

Adult↗

PubMed2003

Finite element analysis of the possible mechanism of cervical lesion formation by occlusal force.

Recently, various authors have proposed the interesting idea that occlusal force may be a principal factor in cervical lesions of the tooth. It is speculated that the lateral force in non-ideal mastication causes the tooth to bend and that the resulting tensile stress damages the enamel surface. In this study, we carried out stress analysis on the upper central incisor and the lower first molar using the plastic-elastic deformation theory with two-dimensional finite element method (FEM). The essential feature that the tensile yield strength is much smaller than the compressive one was taken into account. Our results suggested that oblique loading on the tooth stretches the enamel surface near the cemento-enamel junction and causes plastic deformation which eventually leads to the cervical lesion.

Bite Force↗

PubMed2003

A comparison of the erosive susceptibility of cuspal and cervical enamel using an ultrasonic technique.

The aim of this study was to compare the erosive susceptibility of cuspal and cervical enamel from human premolar and molar teeth. Small blocks of cervical and cuspal enamel were immersed in either orange juice or Coca-Cola at 37 degrees C and the surface enamel loss was measured by surfometry at 1, 2, 3 and 4 h. Additionally, once-hourly enamel loss was measured, specimens were placed in an ultrasonic bath containing water and ultrasonicated for 5 s to determine the degree of surface demineralization. A further set of enamel specimens were prepared that had 100 microm of the enamel surface removed. This was done to remove the hypermineralized surface enamel layer. Surface enamel loss in orange juice at 4 h, following ultrasonication, ranged from 13.2 to 16.9 microm. The surface enamel loss in Coca-Cola at 4 h, following ultrasonication, ranged from 21.7 to 27.5 microm. Subsurface enamel loss in orange juice at 4 h, following ultrasonication, ranged from 10.7 to 16.1 microm. The subsurface enamel loss in Coca-Cola for 4 h, following ultrasonication, ranged from 36.8 to 37.2 microm. Overall, little difference was found in the erosive susceptibility of cervical and cuspal enamel to the effects of orange juice or Coca-Cola.

Bicuspid↗

PubMed2004

The long-term effectiveness of five current desensitizing products on cervical dentine sensitivity.

The aim of this study was to compare the long-term effectiveness of five desensitizing products on 25 male and 27 female patients (total 52) aged 21-67 years (mean 36 +/- 7 years) suffering from cervical dentine sensitivity. All subjects were seen by the same examiner (ID) who was blinded to the applied treatment for 3-month clinical study. Patients were asked to record their overall sensitivity by marking a point on a 10 cm Visual Analogue Scale (VAS). Two hundred and seventy-seven sensitive teeth were treated by one of the five desensitizing products, all of which were placed following manufacturers' instructions by the other investigator (AS). A paired (split mouth) study design was used and selection of quadrants was randomized. At the post-treatment and at 10 days and 3 months periods, sensitivity measurements were recorded by the same investigator (ID). Statistical analysis showed that all of the VAS scores at post-treatment evaluation points were significantly decreased compared with baseline data (P < 0.05). There was a significant reduction in mean sensitivity scores in the Protect Liner F and the Health-Dent Desensitizer groups when compared with Fluoline varnish at the 10-day time point (P < 0.05). At 3 months, the Protect Liner F group continued to show a significantly reduced sensitivity level when compared with Health-Dent Desensitizer, Single Bond, Fluoline and Gluma Desensitizer (P < 0.05). The present study demonstrated that although at the end of 3-month evaluation period all desensitizers showed lower VAS sensitivity values compared with baseline, there were differences in the level of reduction of cervical dentine sensitivity.

Adult↗

PubMed2003

Effect of variable moderate chronic stress on ligature-induced periodontal disease in Wistar rats.

The aim of this investigation was to study the impact of stress on ligature-induced periodontal disease in rats by means of a variable moderate chronic stress model. Thirty male Wistar rats were randomly assigned to six groups. Control groups received only ligatures around the second maxillary molars, while experimental groups were exposed to stress in additional. Stress was imposed by means of flashing light, isolation, rat blood smelling, new environment exposure, immobilization in cold temperature and immobilization at room temperature. Stress was applied randomly, thereby diminishing adaptation of the animals to the model. The animals were killed after 29, 43, and 57 days. The distance between the cementum-enamel junction and the alveolar bone (CEJ-AB) was measured. Alveolar bone loss was statistically different between stressed and control animals, whereas differences were not observed between experimental periods. The mean CEJ-AB distance in animals exposed to stress was 154.50 microm smaller than the corresponding distance in the controls. It might be concluded that variable moderate chronic stress decreased alveolar bone loss in a ligature-induced periodontal disease model.

Alveolar Bone Loss↗

PubMed2005

An 18-months' evaluation of self-etch and etch & rinse adhesive in non-carious cervical lesions.

OBJECTIVE: In this intra-individual comparison (an 18-months' randomized, controlled prospective study), we evaluated the clinical performance of one self-etch and one "etch & rinse" adhesive in non-carious cervical lesions. METHODS: Twenty-five patients with at least two pairs of similar-sized non-carious cervical lesions participated. Seventy-eight restorations were placed; 39 with etch & rinse (Single-Bond) and 39 with self-etch (Adper Prompt). Both adhesives were combined with the microfilled resin composite Filtek-A110. The restorations were evaluated at baseline, 6, 12, and 18 months according to slightly modified USPHS criteria. Statistical differences between the adhesives was tested with McNemar's test and clinical degradation over time for each material with the Fisher exact test (a=0.05). RESULTS: Thirty pairs were evaluated at 12 and 18 months. Two self-etch restorations were lost after 18 months. Nine Adper Prompt and four Single-Bond restorations scored bravo for marginal adaptation at 18 months (p<0.05). Nine Adper Prompt and three Single-Bond restorations scored bravo for marginal discoloration (p<0.05). CONCLUSIONS: Both adhesive systems showed acceptable clinical retention rates according to the ADA full acceptance criteria for enamel-bonding systems in class V non-carious lesions. The self-etch adhesive showed a faster progressive marginal degradation.

Acid Etching, Dental↗

PubMed1999

Cervical thickness of the mandibular alveolar process and skeletal bone mineral density.

Much effort has been devoted to finding methods for detecting individuals with low bone mass and risk of osteoporotic fractures. The aim of the present study was to investigate whether there is a relationship between the thickness of the alveolar process and the bone mineral density (BMD) of the distal forearm. In 24 women (38-65 years), the BMD of the distal forearm, obtained by dual X-ray absorptiometry, was correlated to the difference between two measures of the thickness of the mandibular alveolar process in the region of the first premolar. A highly significant correlation (r = 0.95, P< 0.001) was found. The method was cross-validated by using the equation obtained from the linear regression analysis above to predict BMD in two other groups. In both groups, the correlation between the measured BMD of the forearm and the predicted BMD was highly significant (r = 0.91, P< 0.001). The interdental thickness between the canine and the second incisor was also correlated to BMD, but with lower predictive value (r = 0.67, P<0.001). Measurements of the mandibular alveolar process can be used as one of several parameters to predict skeletal bone density.

Absorptiometry, Photon↗

PubMed2003

Abfraction and anisotropy--effects of prism orientation on stress distribution.

This work discusses the effect of enamel anisotropy in the stress concentration at the cement-enamel junction (CEJ), a probable cause of fracture in enamel leading to abfraction. Usual simplifications when developing computer models in dentistry are to consider enamel isotropic, or that the direction of the prisms is orthogonal to either the dentine-enamel interface or the tooth outer surface. In this paper, a more refined model for the material behavior is described, based on laboratory observation and on the work of Fernandes and Chevitarese. The material description is used in a two-dimensional (2D) finite element model of the first upper premolar, and the analysis is performed for two different situations: vertical loads, typical of normal mastication and horizontal loads, dominant in bruxism. The analyses were performed using a unit load, which under the hypothesis of linear response of the tooth, allows the combinations described in the text to simulate different functional and parafunctional loads. The results indicate that a realistic enamel description in terms of mechanical properties and spatial distribution of its prisms alters significantly the resulting stress distribution. For all cases included in this study, the detailed description of prism orientation and resulting anisotropy led to improved response in terms of stress distribution, even when loading was horizontal.

Anisotropy↗

PubMed2004

The effects of dietary bioflavonoid (rutin, quercetin, and naringin) supplementation on physiological changes in molar crestal alveolar bone-cemento-enamel junction distance in young rats.

The objective of this study was to evaluate the influence of dietary bioflavonoid (rutin [R], quercetin [Q], and naringin [N]) supplementation on physiological molar crestal alveolar bone(CAB)-cemento-enamel junction (CEJ) distances in young male albino rats. The effects of diets supplemented with 0.57% R, Q, or N, at the expense of dextrose, were tested on 40 young rats, divided into four groups, for a period of 42 days. Rat skulls were defleshed, and CAB-CEJ distance was scored according to the modified method of Keyes and Gold (Oral Surg Oral Med Oral Pathol 1955;8:492). Data were analyzed using one-way analysis of variance, post hoc Tukey's test, and Spearman's (R(2)) correlation. P <.05 was used to reject the null hypothesis. The N group demonstrated the lowest CAB-CEJ distance, followed by the R and Q groups (P <.001-.05), except in the mandibular lingual region, where the Q group had a lower CAB-CEJ distance than the N and R groups (P <.05). The control group showed the largest CAB-CEJ distances. Dietary bioflavonoid supplementation was shown to significantly reduce molar CAB-CEJ distance (P <.001-.05) during alveolar development in male young rats.

Animals↗

PubMed1996

The advantage of CO2-treated dental necks, in comparison with a standard method: results of an in vivo study.

Various methods are used for treatment of hypersensitive dental necks. They all aim to seal exposed dentinal tubules, which are open toward the oral cavity and transmit stimuli to the sensitive nerve endings of the tooth pulp. The main sealing materials are fluoride preparations, strontium chloride, and hydroxyapatite. However, these materials must be applied periodically to achieve permanent freedom from pain. Since the introduction of laser technology into dentistry, efforts have been made to treat dentine hypersensitivity with the laser. An in vitro study revealed that CO2 laser irradiation results in almost complete closure of the dentinal tubules in the dental neck region. In the present in vivo study, the efficacy of laser treatment was examined in 72 patients with dentine hypersensitivity and 72 control patients over a period of 12 weeks. When success was defined as complete freedom from pain, the success rate in the laser group was 94.5%; when marked pain relief was included in the definition of treatment success, 98.6% of the patients were treated successfully. Treatment of the control group with conventional dental neck fluoridation resulted in no marked improvement. Laser Doppler measurements of pulpal blood flow immediately before and after treatment revealed no effects of laser irradiation on pulpal blood flow. Dentine samples were obtained from the dental necks 6 weeks after laser treatment and examined with atomic absorption spectroscopy (AAS). Tin was present in the samples, which suggests that the combined laser treatment and fluoridation result in permanent integration of fluoride in the dentine surface.

Adult↗

PubMed1998

Long-term effects of CO2 laser irradiation on treatment of hypersensitive dental necks: results of an in Vivo study.

OBJECTIVE: The present in vivo study was performed to examine the long-term effects of combined CO2 laser treatment and fluoridation on hypersensitive dental necks. SUMMARY BACKGROUND DATA: Attempts have been made to treat dental hypersensitivity by sealing exposed dentinal tubules, primarily using fluoride preparations, strontium chloride, and hydroxyapatite. However, these treatment methods have the disadvantage that the preparation is effective only for a limited period of time and must be applied repeatedly, at short intervals. The CO2 laser has been shown to have an excellent sealing effect on hypersensitive dentinal surfaces. METHODS: Test subjects suffering from dentinal hypersensitivity were recruited from the patients of the Department of Conservative Dentistry, School of Dentistry of the University of Vienna, Austria and treated with combined laser irradiation and fluoridation with stannous fluoride gel. The patients were followed up for a period of 18 months. In vivo examinations were supplemented by atomic absorption spectroscopy (AAS) of tiny dentin samples obtained from the dental necks 6 weeks and 18 months after laser treatment and by scanning electron microscopy (SEM). RESULTS: Compared to conventional fluoridation, combined laser irradiation and fluoridation was shown to be effective in the treatment of hypersensitive dental necks. When success was defined as complete freedom from pain, the success rate in the laser group was 96.5%. Furthermore, examinations of irradiated teeth under the scanning electron microscope still revealed complete closure of the dentinal tubules four and six months after laser treatment. AAS showed that tin was present in the samples, which indicates that combined laser treatment and fluoridation result in permanent integration of fluoride in the dentin surface. CONCLUSIONS: Based on these results, the CO2 laser can be recommended as an ideal tool for desensitization of dental necks.

Adult↗

PubMed2005

The effects of dietary naringenin supplementation on physiological changes in molar crestal alveolar bone-cemento-enamel junction distance in young rats.

The objective of this study was to evaluate the influence of dietary naringenin (NAR) supplementation on physiological molar crestal alveolar bone (CAB)-cemento-enamel junction (CEJ) distances in young male albino rats. The effects of diets supplemented with 0.09%, 0.18%, 0.36%, and 0.72% NAR, at the expense of dextrose, were tested on 40 young rats, divided equally into five groups, for a period of 42 days. Rat skulls were defleshed, and CAB-CEJ distance was scored according to the modified method of Keyes and Gold. Data were analyzed using one-way analysis of variance, post hoc Tukey's test, and Spearman's (R(2)) correlation. P < .05 was used to reject the null hypothesis. NAR showed a statistically significant inverse dose-dependent relationship on CAB-lingual alveolar bone distance (P < .05). In all cases lingual CAB-CEJ distance was larger than buccal CAB-CEJ distance. Thus dietary NAR supplementation was shown to significantly reduce molar CAB-CEJ distance (P < .001-.05) during alveolar development in young male rats.

Analysis of Variance↗

PubMed2005

Marginal leakage in class V cavities pretreated with different laser energy densities.

The purpose of the present study was to evaluate in vitro the degree of marginal leakage in Class V cavities involving the cementoenamel junction. Cavities were 4 mm wide and 2 mm deep. The specimens received dentin pretreatment (37% phosphoric acid) followed by the Single Bond (3M) adhesive system application. The 40 specimens were then divided into four groups: Group 1 (control); Group 2 (Nd:YAG laser at 120 mJ/pulse, frequency of 10 Hz, power of 1.2 W); Group 3 (Nd:YAG laser at 140 mJ/pulse, frequency of 10 Hz, power of 1.4 W); Group 4 (Nd:YAG laser at 160 mJ/pulse, frequency of 10 Hz, power of 1.6 W). The cavities were restored with Z100 composite resin (3M) and light cured at 300-600 mW/cm2 light intensity. Specimens were thermocycled to 500 cycles from 2-50 degrees C. After that, they were dried and sealed with nail varnish, respecting 1 mm around the restorations, and immersed in 0.5% methylene blue solution for 4 h. After this period, the teeth were rinsed, dried, sectioned, and analyzed in a stereoscopic loupe. The highest leakage scores were considered for each specimen. The results were statistically analyzed by the analysis of variance (ANOVA) - Kruskal-Wallis test to the 5% level. For both the enamel and cementum, there was a decrease in marginal leakage with the application of laser energy; no significant differences were observed for Groups 2, 3, and 4. The results also showed a smaller tendency to marginal leakage on the cementum than on the enamel.

Analysis of Variance↗

PubMed1997

A 3-year follow-up study of various types of orthodontic canine-to-canine retainers.

The present study was performed to test the tendency for plaque and calculus build-up along the wire of different types of bonded orthodontic canine-to-canine retainers, whether the presence of such retainers causes any damage to the teeth involved, the failure rate of the retainers, and any changes in incisor alignment during a 3-year period of retention. The four test groups received either retainers made of thick plain wire bonded only to the canines (n = 11); thick spiral wire bonded only to the canines (n = 13); thin, flexible spiral wire bonded to each tooth (n = 11); or removable retainers (n = 14). Accumulation of plaque and calculus along the gingival margin, gingival inflammation and probing attachment level were scored in lingual areas from canine to canine at the time of fixed appliance removal and again 3 years after retainer insertion. Incisor irregularity was measured on plaster models made at the same time periods. Accumulation of plaque and calculus and development of caries along the wire were scored at follow-up. Retainer failures were recorded whenever they occurred. The results revealed no intergroup differences in changes between baseline and follow-up examinations or status along the retainer wire for any of the variables. Gingival inflammation and plaque accumulation were scored less frequently after 3 years in retention than at the time of debonding. No signs of caries were seen adjacent to the wire. Failures were observed of one, four and three of the fixed retainer types, respectively. These patients showed a greater increase in incisor irregularity than the other patients.

Adult↗

PubMed2000

Efficacy of final irrigation--a scanning electron microscopic evaluation.

The purpose of this in vitro study was to determine the degree of removal of pulpal remnants and smear layer from root canals after final irrigation with three different solutions. During instrumentation the step-back preparation and 1% NaOCl were used. The final 4-min, 30-ml irrigation varied as follows: group I, 10 ml of 1% NaOCl + 10 ml of 10% citric acid + 10 ml of distilled water; group II, 15 ml of 0.5% NaOCl + 15 ml of EDTA-T; and group III, 10 ml of 5% NaOCl + 10 ml of 3% H2O2 + 10 ml of 5% NaOCl. Scanning electron microscopic photomicrographs were evaluated for the mean number of visible open dentinal tubules by three observers. The largest number of visible tubules in the three groups was in the cervical third, followed by the middle and apical thirds. There was no statistically significant difference between groups I and II when third was compared with third; however, groups I and II had significantly more visible dentinal tubules than group III.

Acid Etching, Dental↗

PubMed2001

Permeability characteristics of bovine and human dentin under different pretreatment conditions.

In order to use bovine dentin instead of human dentin for in vitro adhesion and cytotoxicity tests the permeability characteristics of human and bovine dentin should be similar. In the present study hydraulic conductance (Lp) and diffusional water flux (J5) of human and bovine dentin slices were compared. The permeability experiments were performed in a split chamber using tritiated water in physiological saline. Lp and Js of bovine dentin were 0.7- to 2.4-fold and 1.1- to 3.5-fold that of human dentin (not statistically significant). For human and bovine dentin Lp and Js increased with etching and showed an inverse linear relationship (r > or = 0.7) with dentin thickness. The variability of bovine data was low (perfusion = 30%, diffusion = 22%) and about half that of the human data. In conclusion bovine dentin near the cementoenamel junction seems to be a suitable alternative for coronal human dentin for in vitro tests with respect to transdentinal permeability characteristics.

Acid Etching, Dental↗