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PubMedDate not supplied

Comparison of in vivo and in vitro demineralized dentin with phosphoric and maleic acid.

This article evaluated possible differences between dentin conditioned in vivo and in vitro with 10 percent maleic acid or with 36 percent phosphoric acid. Semispherical Class V cavities were prepared in vivo and in vitro at the cementum-enamel junction and were divided into four groups. After etching procedures, the in vivo samples were extracted and fixated in 10 percent buffered formaldehyde. Both the in vivo and in vitro samples were then fractured in two parts along their long axis, critical-point dried, and subsequently examined with SEM. Both the acids removed completely the smear layer and demineralized the dentin, leaving a layer of collagenous network. No morphological differences were found between in vivo and in vitro dentin samples.

Acid Etching, Dental↗
PubMed1997

An investigation of potential desensitizing agents in the dentine disc model: a scanning electron microscopy study.

Cervical dentine sensitivity (CDS) may be defined as pain arising from exposed dentine. The prefix cervical indicates the location of the sensitivity and/or its subsequent treatment. Currently the most accepted mechanism of intradental nerve activation associated with dentine sensitivity appears to be hydrodynamic in nature. The concept of tubule occlusion as a method of dentine desensitization is a logical conclusion of the hydrodynamic theory. The authors employed the dentine disc model, qualitative scanning electron microscopy (SEM) and X-ray microanalysis to investigate whether selected desensitizing agents occlude dentinal tubule orifices. Strict control procedures have been used together with various methods of application to apply these agents to human dentine discs. SEM was used to examine the degree of deposit left by the various agents on disc surfaces and X-ray microanalysis was employed to characterize the elemental composition of the deposit. Analysis of selected agents, both prior to and after application on dentine discs was performed for comparative purposes. The degree of retention of the surface deposit upon rotation with saliva supernatant for 6 h was also studied. The results of this study indicated that ferric oxalate, the active ingredient of Sensodyne Sealant, which produced initial crystal-like structures, occluding almost all the tubule orifices was superior to potassium oxalate (Butler Protect). Of the over-the-counter (OTC) desensitizing products tested, both silica- and calcium-based abrasive components were observed both on the surface and within the tubules, indicating a certain degree of therapeutic potential for these two components. These findings suggest that certain desensitizing agents have tubule occluding properties as observed in this in vitro system which, in turn, may indicate a therapeutic potential in vivo.

Calcium↗
PubMedDate not supplied

An unusual case of cervical root resorption.

Supraosseous extracanal invasive root resorption was diagnosed based on a radiographic survey, clinical examination, and microscopic examination of pulpal and exophytic soft-tissue specimens. Microscopic pulpal examination showed little or no evidence of significant inflammation. This resorptive process demonstrates extensive noncarious destruction of dentin without affecting pulpal health.

Adult↗
PubMedDate not supplied

Rapidly progressing extracanal invasive resorption.

Frank and Bakland coined the term "Extracanal invasive resorption" (EIR) to identify a resorptive entity that has been variously classified. This external resorption originates in the cementum adjacent to the periodontal ligament. The lesion is believed to be a response to injury and irritation of the periodontal ligament, or to pressure from ectopic eruption, orthodontic pressure, intracoronal bleaching, periodontal treatment, or an unknown idiopathic cause.

Adult↗
PubMed1997

Microleakage of cervical restorations etched with a weak organic acid.

This in-vitro study evaluated the microleakage of Class V restorations prepared using 10 per cent maleic acid and a composite resin. Thirty human premolar teeth were evenly distributed and randomly assigned to three groups. Conventional retentive preparations, etched with 10 per cent maleic acid for either 15, 30, or 60 seconds, were cut in the enamel on the facial surface of each tooth to a 1.5 mm depth (dentin). All teeth were restored with Z-100, a small particle composite resin. The teeth were then stored in deionized water for seven days, thermocycled, stained with methylene blue dye, invested, and sectioned vertically through the centre of the restoration. Leakage was established along each wall of the sectioned restoration. Analysis of variance (ANOVA) tests indicate that the restored teeth in Group 1 (15-second etch) had significantly greater microleakage (p < 0.05) on the enamel wall than the restored teeth in Group 2 (30-second etch) or Group 3 (60-second etch). In addition, Group 1 restorations had significantly greater overall microleakage (p < 0.05) than Group 2 or Group 3 restorations. Although the results were not statistically significant, it would appear that etching with 10 per cent maleic acid for 30 seconds could be clinically significant. Since a 30-second etch time was found to produce the least amount of microleakage (not statistically significant), it can be assumed that this etch time would also be optimal for etching enamel and dentin. Similarly, since Group 1 revealed the most overall microleakage, it can be assumed that a 15-second etch would be inadequate for etching enamel and dentin. Restorations in Groups 2 and 3 displayed statistically significant lower overall microleakage results.

Acid Etching, Dental↗
PubMed1996

[Study on experimental cervical defect of human tooth by SEM].

Experimental cervical defects on 12 pairs of premolar caused by cross-brushing, erosion and occlusal force separately or together were observed under SEM Changes on the surface of cervical defects suggested that the defects were induced by the above three factors combined. It was interesting that various kinds of microcracks were noticed on sections of enamel and dentin at the cervical defect areas made by mimicking occlusal force combined with other factors. The results seemed to indicate that the occlusal force would play an important role on formation of the cervical wedge-shaped defect and that accumulation of the stress caused the hard tissue injured and microcracked.

Adolescent↗
PubMed1997

[Analysis of divergent angle and length of CEJ to furcation entrance in extracted molars].

The purposes of this study were to investigate the furcation entrance angle (FEA) and the distance between cemento-enamel junction (CEJ) and furcation entrance (FE) of the extracted maxillary and mandibular molars. Assay teeth comprised 89 maxillary molars and 93 mandibular molars. All the FEAs and CEJ-FEs of the molars were measured by a stereomicroscope at 2.5 x equipped with a Bioscan OPTIMAS Image Analyzer (BOIA). The results were summarized as follows: (1) The mean FEAs in the buccal, mesial and distal furcations were 96.3 +/- 10.0, 103.8 +/- 9.7, and 107.2 +/- 12.2 degrees in the maxillary molars, and 91.6 +/- 11.7, 101.7 +/- 11.5, and 97.1 +/- 10.7 degrees in the maxillary second molars, respectively. At the buccal and lingual furcations of mandibular first and second molars, they measured 100.5 +/- 9.7/102.7 +/- 8.5, and 93.3 +/- 11.5/91.7 +/- 10.8 degrees, respectively. (2) The mean distance of CEJ-FEs at the buccal, mesial and distal furcations of maxillary molars were 3.42 +/- 1.5mm, 3.55 +/- 0.97 mm, and 3.69 +/- 0.98mm for the first molars, and 3.01 +/- 1.04mm, 4.04 +/- 1.58mm and 3.00 +/- 1.14mm for the second molars. At the buccal and lingual furcations of the mandibular first and second molars, they were recorded as 1.90 +/- 0.08mm and 2.90 +/- 0.07mm, and 2.82 +/- 1.34mm and 3.46 +/- 1.03mm, respectively. It was concluded that buccal FEA of maxillary 2nd molar was the smallest (91.56 +/- 9.68 degrees) as compared to the mesial and distal FEAs; whereas the mean distance of CEJ-FEs at the buccal surface was the smallest (1.90mm +/- 0.08mm) when compared to the others.

Humans↗
PubMed1997

The relationship between cervical enamel projection and class II furcation defects in humans.

The purposes of the present study were to examine the frequency of cervical enamel projection in mandibular molars with class II furcation defects and to examine the response of these teeth to guided tissue regeneration procedures. Probing depth and vertical and horizontal periodontal attachment levels were recorded with a constant-force electronic periodontal probe. Following surgical exposure of the bifurcation and prior to membrane placement, the cervical enamel projection was examined and then graded clinically; photographs were taken to allow further examination of the bifurcation. An overall improvement in clinical parameters was observed in most sites. Cervical enamel projection was present in 82.1% of all molars examined. Grade II was the most prevalent (34.8%). Patients with any degree of cervical enamel projection demonstrated significantly higher mean probing depths at baseline than did patients without cervical enamel projection. Likewise, pretreatment probing attachment levels were higher in patients with some degree of cervical enamel projection. However, greater posttreatment horizontal and vertical attachment gains were observed in sites with a baseline cervical enamel projection.

Analysis of Variance↗
PubMed1996

The effectiveness of desensitizing agents for the treatment of cervical dentine sensitivity (CDS)--a review.

The treatment of dentine sensitivity or cervical dentine sensitivity (CDS) has been in the form of dentifrices, mouth rinses, sealants, and other therapeutic techniques. Claims of efficacy of the "so-called" active ingredients of these desensitizing agents have been made on the basis of the proposed mode of action generally extrapolated from in vitro or animal studies. Evidence from published, well-controlled clinical studies, however, generally has failed to substantiate such claims, although there has been a reported significant reduction in discomfort by subjects participating in these studies. Currently, the most accepted mechanism of intradental nerve activity associated with dentine sensitivity appears to be hydrodynamic in nature, although other mechanisms cannot be eliminated. The concept of tubule occlusion as a method of dentine desensitization is a logical conclusion from the hydrodynamic hypothesis. This paper reviews the present position with regard to the treatment of dentine sensitivity by various desensitizing agents and evaluates their claims of efficacy in the context of available scientific evidence.

Animals↗
PubMedDate not supplied

Classification of cervical burnout and its distribution in the dentition.

A retrospective analysis of 25 full mouth intra oral radiographs, including bitewing films was carried out from the hospital records of King Saud University College of Dentistry in Riyadh, Saudi Arabia, A new classification of cervical burnout (CB) based on shape was attempted. Analysis of the data revealed greater frequency of CB in maxillary teeth (67.5%) than in the mandibular teeth (32.5%). The highest frequency among maxillary teeth was in incisors (75%), while the least was in the molars (30%). In mandible, the corresponding findings was in the canines (40%) and in the molars (15.3%). Seventy per cent of CB disappeared in bitewing view in maxillary and mandibular premolars while remaining teeth showed this phenomenon in less than 50% cases. It was concluded that the frequency of CB was greater in maxillary teeth than mandibular teeth. Maxillary incisors and mandibular canines are more likely to show CB. In molars and premolars, CB present in periapical radiographs may disappear in a bitewing view.

Adolescent↗
PubMed1995

Influence of laser enamel and dentine etching on marginal integrity of porcelain laminate veneers.

This investigation evaluated the effect of laser etching and acid etching techniques on the marginal leakage Vitadur N porcelain laminate veneers bonded either entirely on enamel, or with cervical margin located on root dentine of prepared extracted maxillary central incisors. Two different composite resin luting systems (light cured, or light and chemical cured) were used and compared. The bonded specimens were thermocycled and by employing the Standard dye penetration technique the leakage was scored from cervical and incisal margins. The least marginal leakage was observed beneath laminate veneers bonded entirely on enamel. Laser etching improved the sealing qualities of veneers with cervical margins on root dentine below the CEJ. Statistically insignificant differences were observed with the use of the two different composite resin luting systems.

Acid Etching, Dental↗
PubMed1995

Influence of linear expansion of two different non metallic core materials upon cervical marginal accuracy of full veneer crowns.

The effect of water sorption and linear expansion of two different non metallic core materials: 1) Composite and 2) Reinforced glass ionomer on the cervical marginal seating of cast metal crowns was investigated in this study. Thirty freshly extracted sound mandibular molar teeth were used in this study. The teeth were machined cut to simulate average dimensions of a prepared lower second premolar tooth with chamfer finish line. The teeth were decoronated 2 mm above the finish line then specially prepared to receive equal volumes of either pin retained composite or pin retained reinforced glass ionomer. The teeth after that were restored with full coverage metal crowns. Ten of each type of core samples were immersed in 37 degrees C normal saline while the remaining samples were maintained dry (control). The vertical cervical marginal accuracy of the crowns were microscopically measured with 1 micron accuracy before immersion and after 6, 12 hours and every day of the following ten days of saline immersion. The statistical analysis of the results revealed that composite core immersed in saline solution at 37 degrees C possessed dimensional instability with the maximum linear change between the first and the second day. Also the reinforced glass ionomer core showed no effect upon the cervical marginal seating of the overlying full coverage cast metal crown.

Analysis of Variance↗
PubMed1996

Microleakage of multi-step and simplified-step bonding systems.

PURPOSE: To measure and compare the microleakage of Class V resin composite restorations using the following three pairs of multi- and simplified-step dentin bonding systems (DBS): OptiBond vs. OptiBond FL, All-Bond 2 vs. One-Step, and Tenure vs. Tenure Quik. MATERIALS AND METHODS: V-shaped cavities were prepared in the mesial and distal surfaces of 30 extracted human mandibular molars with margins in both enamel and cementum, and randomly assigned into three equal groups of 10 each. All DBSs were applied strictly following manufacturers' specifications before three incremental layers of resin composite (Pertac-Hybrid) were applied in all cavities. Specimens were stored for 7 days in 37 degrees C water, thermocycled for 300 cycles between 5 degrees C and 55 degrees C, immersed in 0.5% basic fuchsin solution for 24 hours, and embedded in resin before being sectioned longitudinally in multiple sections. Dye solution penetration at the tooth/composite interface was scored from 0 to 4 under a microscope at x100 at both enamel (E) and cementum (C) margins. Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests with alpha = 0.05. RESULTS: OptiBond FL and One-Step showed less microleakage at the cementum margins compared to their multi-step versions. At the enamel margins Tenure Quik showed less microleakage compared to Tenure, and none of the other DBSs tested showed significant dye penetration at that interface. All DBSs showed significantly less microleakage at the enamel margins compared to the cementum margins except for OptiBond FL and One-Step that did not show any significant dye penetration at the cementum margins as well.

Analysis of Variance↗
PubMedDate not supplied

Rubber dam isolation of cervical lesions. Part 1: Alternative techniques which avoid injury to the periodontium.

While it is arguable that the operative procedures depicted in this article could have been done equally well with alternative forms of isolation, it is indisputable that rubber dam provides for the most thorough 'isolation' in the comprehensive sense of the term. It allows for the finite control over peripheral variables such as access and controlled gingival retraction. This in turn permits meticulous execution of restorative procedures within the luxury of 'true four-handed dentistry'. Most operative procedures are done within the limitations of single handed dentistry as the other 'three hands' are involved with retraction, fluid evacuation and access control. The rubber dam is indeed indispensable and with the increased awareness of infection control it is conceivable that rubber dam isolation will continue to be associated with quality patient care. Part 2 of this article will detail the application of the 'Modified Gingival Retractor' in the isolation of cervical lesions.

Constriction↗
PubMed1995

A new copolymerized composite resin system: a multiphased evaluation.

Most microfilled composite resins are relatively resistant to generalized wear; however, they commonly exhibit poor resistance to localized wear because of debonding of prepolymerized particles from the resin matrix. A copolymerized new composite resin, in which the filler particle trimethylolpropane-trimethacrylate is chemically bonded to the resin matrix, is evaluated. Epic-TMPT was subjected to both generalized and localized wear tests that revealed that its wear resistance was higher than that of other composite resin systems. Epic-TMPT in posterior occlusal cavities showed less than 8 microns of wear for each restoration, 1 year after placement. Placement of Epic-TMPT into large anterior abfraction lesions without mechanical retention, with surface etching, and subject to severe traumatic occlusion resulted in 87% retention 1 year after placement. In vivo usage biocompatibility tests demonstrated no pulpal irritation or inflammation when Epic-TMPT was placed on vital dentin of crown preparations with complete enamel removal.

Animals↗
PubMed1998

Microleakage of tooth-colored restorations with a beveled gingival margin.

OBJECTIVE: Microleakage of tooth-colored restorative systems was tested in preparations with and without beveled gingival margins. METHOD AND MATERIALS: A resin composite, Z-100, and two "compomer" restoratives, Dyract and Geristore, with their accompanying adhesive systems, were placed in nonretentive cervical cavity preparations (at the cementoenamel junction), with and without a beveled gingival margin (dentin or cementum) and beveled occlusal (enamel) margins in extracted bovine teeth. Microleakage was assessed as the ratio of the extent of methylene blue dye penetration at the tooth-restoration interface of the length of the wall. RESULTS: Z-100 restorations, without a gingival bevel, exhibited significantly less microleakage along the gingival wall and less microleakage overall than did the other materials. Dyract restorations without a gingival bevel and placed without a surface conditioner displayed greater microleakage overall than did the other groups. CONCLUSION: With all materials, Class V restorations with gingival bevels displayed greater microleakage than did nonbeveled margins.

Analysis of Variance↗