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PubMed2006

Cementoenamel junction of deciduous teeth: SEM-morphology.

AIM: The aim of this study was to investigate the cementoenamel junction of a group of 11 primary sound mandibular incisors extracted for orthodontic reasons. MATERIALS AND METHODS: Eleven caries and defect-free human inferior deciduous incisors were extracted for orthodontic reasons and the cementoenamel junction was investigated by scanning electron microscopy (SEM). The types of tissue interrelations were classified in four possible categories: 1) cementum and enamel edge-to-edge, 2) cementum overlapped by enamel, 3) enamel overlapped by cementum, 4) presence of exposed dentin between enamel and cementum. RESULTS: In our observations root cementum and enamel edge-to-edge interrelation was the most frequent feature observed in overall sample, root cementum overlapping enamel tissues was observed in more than one third of the cementoenamel junction area, exposed dentin was a rare observation. In few, small and rare areas enamel overlapped cementum. Further studies could determine statistical prevalence. CONCLUSION: The cementoenamel junction of primary teeth differs from that of permanent teeth, the scarcity of gaps between cementum and enamel, the epithelial junction at the equator of the crown and the globosity of the crown are probable protective factors toward decay susceptibility.

Child↗
PubMed2006

One-year clinical evaluation of two resin composites, two polymerization methods, and a resin-modified glass ionomer in non-carious cervical lesions.

AIM: The aim of this study was to examine clinically relevant data on four restorative procedures for non-carious cervical lesions using United States Public Health Service (USPHS)-compatible clinical and photographic criteria and to compare different methods of analyzing clinical data. METHODS AND MATERIALS: Fourteen patients with at least one or two pairs of non-carious lesions under occlusion and a mean age of 50 were enrolled in this study. A total of 56 restorations (14 with each material) were placed by three experienced, calibrated dental practitioners. Two other experienced and calibrated practitioners, under single-blind conditions, followed up on all restorations for a period of one year. Three materials were randomly placed: a micro-hybrid composite with two polymerization methods (G1 and G2), a flowable micro-hydrid composite (G3), and a resin-modified glass ionomer (G4). Statistical analysis was performed using the Kruskall-Wallis test (p<0.05) and a Mann-Whitney U modified test with a corrected significance level. RESULTS: At the one year evaluation time, there were no restorations with secondary caries and the retention rates in G1 (IntenS with a hard polymerization), G2 (IntenS with a soft polymerization), G3 (Filtek flow), and G4 (Fuji II LC) were 85.7% (two losses), 92.8% (one loss), 100%, and 100%, respectively. The total visual comparison of the results at baseline (15 days later) showed significant differences only with the clinical acceptance criterion: G1 was different from G2, with a soft polymerization device (p<0.05). In terms of surface quality at one year, G1, G2, and G3 exhibited a statistically significant difference from G4, p<0.05. The digital analysis at baseline showed significant differences only with the clinical acceptance criterion: G1=G2 was different from G3=G4, p<0.05. At one year, only the microporosity criterion showed any statistical differences: G1=G2=G3 was different from G4, p<0.05. CONCLUSIONS: The resin-modified glass ionomer was easier to use and had a high retention rate, but it failed in terms of surface quality (visual mode) and porosity (digital mode) criteria compared to the others groups. Overall results showed no difference between groups G1 (hard-polymerized) and G2 (soft-polymerized), and only G1 was affected by the marginal edge (p<0.03) and integrity criteria (p<0.02) at one year.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1989

Access to the rat mandibular molars: a facial surgical approach.

A surgical technique enabling convenient access to the rat molars and their supporting tissues is described. The masseter, the body of the mandible and the alveolar process supporting the molars are exposed via a skin incision, parallel to and immediately in front of the anterior border of the masseter. Denudation of the alveolar process from attached soft tissues permits easy and accurate access to the periodontium of the molars; moreover, separation of the gingival attachment from the tooth cervix exposes the oral cavity and permits convenient and accurate access to the molars. Post-surgical healing is uneventful. The method is easy and convenient, and should prove useful for experimental studies.

Animals↗
PubMed1996

[The cervical third of deciduous teeth. An ultrastructural study of the heard tissues by SEM].

As information on amelocemental junction of deciduous teeth is limited, this topographical area was investigated by scanning electron microscopy (SEM) to verify differences from that of permanent teeth. Twenty-six carious and non-carious human maxillary and mandibular primary teeth were placed in a fixative immediately after extraction. Pulpal tissue was removed from the pulpal chambers and root. The primary teeth blocked onto stubs and all specimens were platinum coated and examined by SEM. In these specimens an overlapping of cementum onto to enamel and an edge to edge relationship was dominant. No gaps between enamel and cementum were observed. The amelocemental junction of deciduous teeth seem to differ to that described for permanent teeth.

Dental Caries↗
PubMed1996

Longevity of glass-ionomer restorative materials: results of a 10-year evaluation.

Three restorative materials used for cervical erosion /abrasion lesions were evaluated clinically after 10 years. Thirty adult patients with at least four cervical lesions received one restoration of each of Ketac-Fil, finished immediately, Ketac-Fil, finished after a delay, Chelon-FIl (all glass-ionomer cements), and Cervident (a resin composite). Restorations were placed without any tooth preparations. Eighteen patients returned for their 10-year examinations. Two experienced examiners provided the periodic evaluations. Complete retention at 10 years was 83% for Ketac-Fil, finished immediately; 78% for Ketac-Fil, finished after a delay; 67% for Chelon-Fil; and 17% for Cervident. All three glass-ionomer restorative materials exhibited statistically significantly greater retention that did Cervident. When a noninvasive procedure is desired, glass-ionomer materials are the restorative material of choice for abrasion/erosion lesions because of their long-term retention values.

Adult↗
PubMed1995

Non-carious cervical tooth loss: Part 1.

Non-carious cervical tooth loss is not always attributable to a single causative factor, as evidenced by the numerous terminologies used. In this, the first of two articles, the aetiology and prevalence of non-carious tooth loss are discussed. Guidelines are suggested as to how it may be diagnosed, prevented and monitored. A further article will cover the restorative management.

Adult↗
PubMed1995

Non-carious cervical tooth loss. Part 2: Management.

The aetiology, prevalence, diagnosis, prevention and monitoring of non-carious cervical tooth loss (NCTL) has been covered in the first article of this series. The aetiology of NCTL is usually multifactorial and may not be attributable to any single factor. Central to the successful management of NCTL is a correct diagnosis of the cause. This article will focus on the management of NCTL.

Composite Resins↗
PubMedDate not supplied

Efficacy of the intramobile connector in implant tooth-supported fixed prostheses: an experimental stress analysis.

An experimental model was designed to evaluate the effects of the intramobile connector in reducing stress concentration in an IMZ implant in fixed connection with a natural tooth abutment. The study analyzed the stresses produced at the cervical level of the implant when the superstructure arm was deflected within the limits of physiologic mobility under static axial loads. The designed experimental model was sensitive to changes in strain data with the applied loads and different internal elements. The intramobile connector resilient component reduced strain up to 60% compared to the rigid internal element.

Dental Abutments↗
PubMed1996

3-year clinical evaluation of modified Gluma adhesive systems in cervical abrasion/erosion lesions.

PURPOSE: To study the clinical performance of two candidates for improvement of the original Gluma bonding system. MATERIALS AND METHODS: Eight teeth with cervical buccal abrasion/erosion lesions were identified in 40 patients. The lesions were conditioned with an oxalic acid solution followed by either a HEMA-glutaraldehyde bonding agent or a formamide-containing bonding agent. The lesions were restored with a hybrid composite. Each patient received the same number of restorations with the two different bonding formulations. All restorations were made by the same operator (JK). Evaluations were based on the USPHS system. RESULTS: No difference between the two groups as to retention, marginal adaptation and discoloration was observed after 3 years. Eight restorations were lost and a slight increase in marginal discoloration was seen during the observation period.

Adult↗
PubMed1995

Protocol for predictable restoration of anterior teeth with composite resins.

The composite resins have reached a high degree of excellence and are now utilized with predictable results in restoring the anterior dentition. This article discusses the development of these resins and the histologic and optical considerations (polychromatic characteristics, hue, translucency and opacity, chroma, value, strength, and polishability). In restorative materials, the use of universal or all-purpose restorative resins is considered, ie, materials that combine the functional strength necessary for the posterior regions and the high gloss polishability necessary to emulate enamel in the anterior. The restorative sequence of cervical, middle, and incisal thirds describes the materials best suited for each third, along with aids to create the intricate refinement of hue, chroma, and value. The learning objective of this article is to review the principles involved in these restorations and to provide a protocol for their clinical implementation.

Clinical Protocols↗
PubMed1997

The Gluma bonding system: a clinical evaluation of its various components for the treatment of hypersensitive root dentin.

This study investigated the desensitizing effect of topically-applied Gluma on sensitive cervical erosion lesions. A total of 46 teeth exhibiting moderate to severe sensitivity to cold and instrumentation, in 15 patients, were included in the study. Mildly sensitive teeth and teeth with cervical caries lesions were excluded from the study. After each tooth was isolated with rubber dam, investigators applied cold air, as well as tactile stimuli using an explorer, and recorded the baseline responses. Nine of the 46 teeth then received Gluma primer only (group 1), 15 received cleanser followed by primer (group 2), 15 received cleanser followed by primer and sealer (group 3), and seven received a placebo (group 4). After two weeks, the teeth in group 4 were randomly placed in one of the other three groups. The responses of the teeth in each group to various stimuli were recorded immediately after the application of test materials, and subsequently at one week, two weeks, one month, three months, six months and one year. Statistical analysis indicates that the three treatment groups all showed significant differences compared to the untreated control group (p < .001). A reduction of sensitivity was noted immediately after primer, cleanser-primer, or cleanser-primer-sealer was applied. Treatment groups 2 and 3 demonstrated less sensitivity than group 1 (p = .02; p = .03, respectively). At the one-year recall, the observed order of treatment effectiveness by group was 2, 3, 1. In approximately 50 per cent of the teeth treated in the study, remission of sensitivity was seen after one year. All of the remaining teeth exhibited some relief of sensitivity. The treatments' success was found to be inversely proportional to the severity of the initial response.

Adult↗
PubMed1996

Cervical contouring concepts: enhancing the dentogingival complex.

The importance of the mucogingival complex in any restorative procedure has long been recognized, and various surgical and nonsurgical procedures have been developed to restore the compromised gingiva to its original health. The learning objective of this article is to review nonsurgical restorative techniques to manipulate the soft tissue surrounding the cervical aspect of the restored tooth into a more favorable contour. The techniques presented are applicable to direct and indirect restorations. Six case reports are used to illustrate the various clinical procedures. The techniques include: Supragingival direct restorative techniques, such as recontouring intact dentition; and intracrevicular indirect techniques, such as recapturing the soft tissue of deficient crown restorations, re-engineering recessed injured tissue, re-creation of hyperplastic injured tissue, re-engineering hyperplastic recessed posttrauma tissue, and re-engineering the periprosthetic envelope.

Collagen↗
PubMed1996

The force requirements for tooth movement. Part III: The pressure hypothesis tested.

Many experiments have investigated the force requirements for tooth movement; the diverse results so obtained have lead to controversy and resulted in an incomplete understanding of the true nature of tooth movement. This study analyses the results of two experiments which investigated the relation between the force applied and the rate of tooth movement from the standpoint of the pressures exerted by the tooth root on the surrounding tooth-periodontal membrane complex. The pressure hypothesis suggested by Smith and Storey is tested using the estimated projected area of the teeth moved in the experiments as a means of calculating the estimated pressures resulting from the application of orthodontic forces. The average pressure at which optimal rates of tooth movement occurred in these experiments was 197 gf cm-2.

Adolescent↗
PubMed1996

Three-year clinical effectiveness of four total-etch dentinal adhesive systems in cervical lesions.

A 3-year follow-up clinical trial of two experimental Bayer total-etch adhesive systems and two commercial total-etch systems. Clearfil Liner Bond System and Scotchbond Multi-Purpose, was conducted to evaluate their clinical effectiveness in Class V cervical lesions. Four hundred twenty abrasion-erosion lesions were restored randomly using the four adhesive systems. There were two experimental cavity designs, in which the adjacent enamel margins either were or were not beveled and acid etched. Clearfil Liner Bond System and Scotchbond Multi-Purpose demonstrated high retention rates in both types of cavity design at 3 years. The two experimental Bayer systems scored much lower retention rates in both cavity designs at 3 years. None of the systems guaranteed margins free of microleakage for a long time. At 3 years, superficial, localized marginal discolorations were observed, the least for Clearfil Liner Bond System, followed by Scotchbond Multi-Purpose and the two experimental systems. Small marginal defects were recorded at the cervical dentin and the incisal enamel margin. Retention of Clearfil Liner Bond and Scotchbond Multi-Purpose appears to be clearly improved over earlier systems, but marginal sealing remains problematic. The two Bayer systems were found to be clinically unreliable.

Acid Etching, Dental↗
PubMed1996

Quantification of the configuration factor in Class I and II cavities and simulated cervical erosions.

The configuration factor of adhesive cavities is defined as the ratio of the restoration's bonded to unbonded (free) surfaces. Such a configuration factor was described, on ideal cavities, as having a potential value in predicting the behaviour of the restorations, because it is related to the restoration's capacity for relieving stress by flow. The aim of this study was to measure the configuration factor value for real Class I and II cavities and simulated cervical erosions prepared in molars. Ten Class I, five Class II cavities and seven cervical erosions were analysed using a computerised digitising system. The configuration factor values found were 4.03 +/- 0.33 for Class I cavities, 1.85 +/- 0.59 for Class II cavities and 1.10 +/- 0.09 for simulated cervical erosions (P < 0.01).

Composite Resins↗
PubMedDate not supplied

An in vitro caries inhibition of photopolymerized glass ionomer liners.

Caries inhibition of traditional chemical cure glass ionomers has been established. The newer photopolymerized glass ionomers demonstrate a different composition that may impair the ability of providing prevention to secondary caries at restoration margins. The purpose of this study was to evaluate the caries inhibition of photopolymerized glass ionomers (Vitrebond-3M Dental Products, Photac Bond-ESPE/Premier Dental Products) compared to a photopolymerized composite resin (Pertac Universal Bond-ESPE/Premier) control. Two standardized Class V preparations were placed in thirty permanent molars, the gingival margin placed below the cementoenamel junction. Equal numbers of preparations were restored with Vitrebond, Photac Bond and Pertac Universal Bond, according to manufacturer's instructions. The teeth were coated with an acid resistant varnish to within 2 mm of the restoration margins. All teeth were subjected to an artificial caries challenge (pH 4.2) for five days, then axial sections of 100 microns were cut longitudinally through the restored margins and photographed under polarized light microscopy. The polarized micrographs were projected onto a digitizing pad, where demineralized areas adjacent to the restoration margins were quantitated. Results demonstrated the mean (+/- S.D.) area (microns2) demineralization 100 microns from the restoration gingival margin to be: Photac Bond 66.1 +/- 27.8; Vitrebond 47.2 +/- 37.2; Pertac Universal Bond 120.9 +/- 66.0. Duncan's multiple range test indicated there was no statistically significant difference in demineralization inhibition between the two photopolymerized glass ionomers Photac Bond and Vitrebond (p < 0.05), but both photopolymerized glass ionomers demonstrated significantly less demineralization than the Pertac Universal Bond composite resin control (p < 0.05).

Dental Caries↗
PubMedDate not supplied

Alveolar bone height of primary and first permanent molars in healthy seven- to nine-year-old children.

The purpose of the study was to establish baseline values of the alveolar bone height of the primary molars and first permanent molars in sample of healthy U.S. seven- to nine-year-old children. Direct measurements of the distance from the cementoenamel junction (CEJ) to the alveolar crest (AC) on 223 pairs of bitewing radiographs from 223 subjects were made using a digimatic caliper under standardized conditions. The distance from the CEJ to the AC had medians from 0.58 mm to 1.39 mm (range 0.0 to 4.44 mm) for the primary molars and from 0.00 mm to 0.64 mm (range -1.35 to 2.15 mm) for the mesial aspect of the permanent molars. There were no statistically significant differences in the distance from CEJ to AC between teeth on the right and left sides of the mouth. The distances from CEJ to AC were always greater in the maxilla than in the mandible for similar primary molar sites, but only true for the mesial aspect of the permanent first molar at age nine. As a tooth is positioned more anteriorly in the mouth, the distance from CEJ to AC was greater. On the whole, males had greater distances than females and eight-year-olds had larger distances than seven- or nine-year-olds. Differences were observed in the measured distances for the different age and sex-groups and may be attributable to variations in eruption and exfoliation patterns. The distance was significantly greater in areas of interproximal restorations and open contacts, and there was a tendency for the distances to be greater in areas of interproximal caries.

Alveolar Process↗