Quintessence International, 05/2001

The success of a dental prosthesis is judged according to function, comfort, phonetics, and esthetics. The purpose of a treatment is to come as close as possible to replicating the natural state. For anterior fixed partial dentures, the all-ceramic system IPS Empress 2 offers light transmission and reflection comparable to that of natural teeth, provided that the pink esthetics are optimized in the preprosthetic treatment phase. In this case report, a laboratory-made provisional was placed after extraction of an anterior tooth. Six months later, preprosthetic periodontal surgery was carried out to enhance gingival harmony. The design of the post and core, preparation, and cementation are important parameters for the success of all-ceramic restorations.

A technique for fabricating complete denture record bases that features flanges augmented with resilient liner is reintroduced and recommended. It is coined the flexible augmented flange technique. The technique takes advantage of the elastic properties of tissue conditioner, available anatomic undercuts in definitive casts, and the rigidity of record base resin to create stable, retentive, well-fitting, and comfortable record bases that minimally abrade casts. Tissue conditioner, which strongly bonds to the intaglio surface of record base flanges, replaces blockout wax to form augmented flanges with flexible inner sections that are sufficiently elastic to engage and then release from undercuts. The flexibility of the inner section of the flanges permits atraumatic insertion and removal from a patient's mouth, despite overall record base rigidity. Accurate, verifiable, maxillomandibular jaw relation records can be obtained with the flexible augmented flange technique.

Orthodontic tooth movement and bone remodeling activity are dependent on systemic factors such as nutritional factors, metabolic bone diseases, age, and use of drugs. Therefore, a comprehensive review of the effects of these factors on orthodontic tooth movement is attempted in this article. Systemic hormones such as estrogen, androgen, and calcitonin are associated with an increase in bone mineral content, bone mass, and a decrease in the rate of bone resorption. Consequently, they could delay orthodontic tooth movement. On the contrary, thyroid hormones and corticosteroids might be involved in a more rapid orthodontic tooth movement during orthodontic therapy and have a less stable orthodontic result. Drugs such as bisphosphonates, vitamin D metabolites, and fluorides can probably cause a reduction of tooth movement after the orthodontic force is applied. Nonsteroidal anti-inflammatory drugs have also been shown to reduce bone resorption. Long-term administration of these drugs may therefore delay the necessary bone response to respective tooth-borne pressure and should not be administered for long periods of time to patients undergoing orthodontic tooth movement. Attention has also been focused on the effects of prostaglandins and leukotrienes in orthodontic tooth movement. It seems that they might have future clinical applications that could result in enhanced tooth movement. The use of the above drugs should be considered by every dentist in evaluating the treatment time and in planning treatment when tooth movement is attempted.

Objective: Dentin hypersensitivity (DH) is a commonly reported dental problem. Conflicting results on the degree of plaque accumulation at sites with DH have been reported. Therefore, the prevalence and distribution of DH and dental plaque were studied in a dental hospital population. Method and materials: A total of 302 adult patients were examined for the presence of DH by means of a questionnaire and intraoral examinations. Oral hygiene was measured by Silness and Löe's Plaque Index. Results: The overall prevalence of DH was 52.6%. Significantly more women complained of DH than men. Dentin hypersensitivity and Plaque Index scores were found to be significantly higher in the older age group than in younger groups. Spearman's correlation test revealed no correlation for DH with plaque. About half of the patients reported DH for a duration of within 1 month, while 23% claimed that their DH lasted for 1 to 5 years. Approximately 64% of the patients reported that sensitivity did not interfere with their ability to eat, drink, or brush their teeth, with slight to moderate discomfort, while 11.4% had a severe concern, thereby avoiding these activities most of the time. Of the patients, 17% received professional treatment, while 25% used desensitizing toothpastes. Dentin hypersensitivity was found in all types of teeth, but was most common in first molars and mandibular incisors and canines. Conclusion: Because there was no correlation for DH with plaque, a careful assessment of the etiologic or predisposing factors must be considered before attempting the management of patients complaining of hypersensitive teeth.

This report intends to show the use of tissue conditioners on esthetic and functional removable partial dentures, placed by the technique of direct relining immediately after surgery to protect the surgical wound and aid the cicatrization.

The aim of this literature review is to discuss the use of dental implants in growing patients and the influence of maxillary and mandibular skeletal and dental growth on the stability of those implants. It is recommended to wait for the completion of dental and skeletal growth, except for severe cases of ectodermal dysplasia.

Objective: The purpose of this in vitro study was to determine the influence of solvent and rewetting time on microtensile dentin bond strengths of four dentin adhesives. Method and materials: Sixty human molar specimens were divided into four dentin adhesive treatment groups: (1) a water-based total-etch dentin adhesive, EBS Multi; (2) an ethanol-based total-etch adhesive, Excite; (3) an acetone-based total-etch adhesive, Prime & Bond NT; and (4) an ethanol- and water-based total-etch adhesive, Single Bond. For each dentin adhesive, three specimens were assigned to five dentin moisture conditions. Specimens were tested in the tensile mode. Results: When adhesives were applied to moist dentin, bond strengths varied from 26.2 MPa for Prime & Bond NT to 29.5 MPa for Single Bond without any statistical differences. When applied to dentin that had been dried for 15 seconds, Prime & Bond NT and Excite resulted in the lowest mean bond strengths, but they were statistically similar to each other (7.9 and 8.3 MPa, respectively). Single Bond resulted in a mean bond strength of 12.7 MPa, which was significantly lower than that of EBS Multi (24.1 MPa). For the latter, all mean bond strengths were statistically similar when some amount of moisture was present on the surface. For the other three adhesives, mean bond strengths returned to the range obtained on moist dentin only when dentin was rewet for 30 seconds. Conclusion: Bond strengths upon rewetting depend on the type of solvent in the bonding system, and rewetting time.

Objective: The purpose of this study was to compare and contrast the performance, in terms of marginal adaptation, of a non-gamma-2 amalgam alloy with a compact-filled light-cured composite in the restoration of Class II preparations of conservative design. Method and materials: Fifty recently extracted teeth were selected for the study. The teeth were restored with either a non-gamma-2 amalgam alloy, Dispersalloy, or a compact-filled resin composite, Z100, using standard techniques. The marginal adaptation of the restorative materials to the proximal surface outline form of each preparation was assessed at magnification 330. Results: Highly significant differences were demonstrated in the mean percentages of perfect margins in all 3 segments of the proximal boxes of the restorations with the resin composite performing significantly better than the amalgam. The percentages of marginal fissuring were significantly higher in the amalgam restorations, except at the cervical margin, where the incidence of fissuring was almost the same for the amalgam and resin composite restorations. The resin composite restorations had significantly fewer underfilled margins than the amalgam restorations. Conclusion: In the conservative Class II preparations, the amalgam restorations were of poor quality with respect to marginal adaptation, compared with the resin composite restorations. It is suggested that the use of amalgam as a control in a clinical evaluation of resin composite restorations in conservative preparations cannot be justified, because it is apparently not possible to compare restorations of equivalent initial quality.

Objectives: This study investigated the prognosis for successful endodontic treatment and the correlation between the size of the periapical lesion, the quality of the root canal treatment, and the type of coronal restoration. Method and materials: Periapical radiographs of 319 teeth with periapical periodontitis were studied. The area of each lesion was measured before treatment and 1 to 12 years after completion of the endodontic treatment. The measurements were performed using computerized morphometry. Results: In 65.2% of the teeth, the size of the lesion decreased, while in 34.8% of teeth, there was an increase. Lesions larger than 10 mm2 had a greater tendency for healing. Conclusion: No significant correlation was found between the quality of root canal treatment, the type of the coronal restoration, and the success rate of the endodontic treatment.

Objective: Microhardness values of upper and lower surfaces of disk specimens of 3 commercially available resin composites were compared and cured using both the traditional halogen source and a plasma arc lamp. Method and materials: Twenty samples of each of the resin composites were cured in nylon washers. Ten samples of each composite were cured using the appropriate halogen lamp protocol, and 10 samples of each were cured using the plasma lamp protocol. Surface microhardness measurements were carried out using a calibrated Vickers indenter on both top and bottom surfaces after 7 days of storage in air at 20°C. Statistical analysis of the data was carried out using a commercial statistical package. The data for top and bottom surfaces were analyzed separately using a repeated measures analysis of variance (ANOVA). Results: Lamp, composite, and the interaction between lamp and composite were significant in determining the results for both top and bottom surfaces of the disk-shaped specimens. The plasma lamp yielded lower hardness values for all surfaces compared with the halogen source, but the size of the difference depended on the composite. Conclusion: Caution must be exercised in the plasma irradiation of resin composites as a curing method due to the possibility of reduced surface microhardness values that may reflect a reduced percent conversion of monomer to polymer.

Objective: The purpose of this study was to evaluate the abrasiveness of a new air polisher on root surfaces. Method and materials: Fifty extracted human teeth were air polished for 5 seconds. Results: All root surfaces showed a circular defect visible with the naked eye. Scanning electron microscope examination showed smooth crater walls and a few open dentin tubules, but most seemed to be obliterated. Laser profilometry of the exposed areas revealed defects with an average depth of 484 µm, whereas the unexposed root surfaces showed irregularities with an average depth of 323 µm. The depths of the abraded areas were evaluated in relation to the values for the unexposed surfaces, and an average depth of 161 µm was found. The difference between the exposed and unexposed surfaces was statistically significant. Conclusion: The present study indicates that the air polisher has a strong abrading effect on exposed root surfaces and should therefore be used with caution on patients with gingival retractions.

Objective: After bleaching treatment, esthetic restorations often need to be replaced due to color changes. Some papers have shown alterations in the bond of adhesive restorations to bleached teeth. The purpose of this study was to evaluate tooth and resin composite adhesion when submitted to nonvital dental bleaching. Method and materials: One hundred and twenty bovine teeth were assigned to 3 groups (n = 40): paste of sodium perborate and water; 37% carbamide peroxide gel; and no bleaching (control). After 3 weeks of continuous bleaching treatment, standardized Class V cavities were prepared at the cementoenamel junction and restored with Single Bond adhesive system and Z100 resin composite. The samples were thermocycled 1,500 times (5 ± 1 / 55 ± 1°C) with a 1-minute dwell time. Then, they were immersed in a 2% methylene blue solution (pH 7) for 4 hours, sectioned, and analyzed by stereomicroscopy. Microleakage analyses were done, using scores from 0 to 4, considering leakage on the incisal wall (enamel) and the cervical wall (dentin). Data were analyzed by Kruskal-Wallis and Mann-Whitney tests (a = 0.05). Results: The results showed that sodium perborate and carbamide peroxide gel significantly increase the microleakage in Class V resin composite restorations to dentin but not to enamel margins.Conclusion: The risk of microleakage in dentin margins is increased soon after bleaching treatment.