Quintessence International, 04/2004

A technique for the restoration of carious primary maxillary incisors using indirect resin composite crowns and intracanal reinforcement fiber is described. Endodontic treatment was previously performed on each tooth. The advantages of using an intracanal reinforcement fiber include resin composite crown reinforcement, translucency, and relative manipulation facility. In addition, the use of indirect resin composite crowns provides good shape and esthetics, as well as reduced chair time for the child. The technique is illustrated in a case report in which indirect resin composite crowns and an intracanal reinforcement fiber are placed in a 3-year-old girl. (

Objective: The purpose of this study was to use wear simulation to develop wear rates for two modern composite systems and then compare these rates with clinical studies on the same materials. Method and materials: A spring-loaded piston wear simulator was used to generate localized wear rates for P50 and Z100 at 100,000, 200,000, 300,000, and 400,000 cycles. Clinical studies on P50 and Z100 conducted at Creighton University and the Catholic University of Leuven were used for comparison of clinical wear to the laboratory values. Regression analysis was employed to define the wear rates. Results: The laboratory wear rates determined with simulation for P50 and Z100 were similar. Clinical occlusal contact area (OCA) wear for P50 and Z100 had small differences and were pooled to provide comparison with laboratory data. Wear rates determined from linear regression analysis provided equivalency factors between laboratory localized wear and clinical OCA wear that could be used for future studies. Further regression analysis comparing OCA and generalized clinical wear allowed a conversion factor of 4.5 to be determined. Conclusion: Localized wear from laboratory simulation may be a useful predictor of localized clinical wear and also clinical generalized wear using a conversion factor.

Objective: Microorganisms are directly associated with the etiology of enamel, dentin, and pulpal pathology. Due to the growing usage of one-bottle bonding materials with resin composite restorations, as well as sealing agents with amalgam restorations, it is important that they possess antibacterial properties. In the present study, the antibacterial properties of polymerized one-bottle bonding agents were tested, using the direct contact test (DCT) and the agar diffusion test (ADT). Method and materials: Quadruple samples of the following materials were tested in both assays: Bond-1, OptiBond Solo, One-Step, Gluma, Prime & Bond NT, and Synergy. In the DCT, samples were placed on the sidewalls of wells of a 96-microtiter plate and polymerized. A 10-µL suspension of Streptococcus mutans was placed on the surface of each sample for 1 hour at 37°C. Fresh media was then added, and bacterial growth was followed with a temperature-controlled spectrophotometer. In the ADT, samples were placed in punched wells of inoculated agar plates, and halos in the bacterial lawn were measured after 72 hours. Results: In the DCT, all the tested bonding agents exhibited potent antibacterial properties; virtually no viable bacteria were present in any of the samples. When the samples were aged in phosphate-buffered saline for 24 hours, all the tested agents, similar to the freshly polymerized samples, exhibited potent antibacterial properties. This property was lost in samples aged for 7 days. Fresh samples assayed by ADT demonstrated no inhibition halo around any of the samples. Conclusion: Collectively, the present data suggest that one-bottle bonding agents possess in vitro antibacterial properties for at least 24 hours. This phenomenon was demonstrated only by DCT.

Fracture resistance of dentin-bonded inlays may be influenced by the restorative material used. The purpose of this study was to evaluate, in vitro, the fracture resistance of teeth restored with four tooth-colored materials: feldspathic ceramic, Duceram LFC, and three laboratory resins, Solidex, Artglass, and Targis. Sixty mandibular molar teeth were placed in resin cylinders, reproducing the periodontal ligaments. Mesial-occlusal-distal (MOD) inlay preparations were made in a standard cavity preparation appliance. Subsequently, the teeth were molded, and the restorations were prepared following the manufacturer's instructions. The inlays were cemented with resin composite cement, Rely X, and stored at 37°C and 100% humidity for 24 hours. The samples were then submitted to an axial compression load at a speed of 0.5 mm/minute. Statistical analysis by one-way ANOVA and Tukey's multiple comparison test revealed that the teeth restored with Duceram LFC (205.44 ± 39.51 kgf) showed statistically inferior fracture resistance than the three other groups restored with indirect resin composites (Solidex [293.16 ± 45.86 kgf], Artglass [299.87 ± 41.08 kgf], and Targis [304.23 ± 52.52 kgf]).

Objective: To measure the convergence angle, incisal/occlusal clearance, and finish line depth, which indicate the amount of axial reduction of full metal-ceramic crown preparations made by final-year dental students. Method and materials: A total of 157 preparations were assessed. Convergence angle and finish line depths were measured by Tool Maker Microscope, while crown height was measured using a digital caliber. Results: The mean convergence angle, faciolingually and mesiodistally, was 22.4 and 25.3 degrees, respectively. The mean for molars was statistically significantly greater than that for other teeth. The incisal/occlusal reduction ranged from 1.8 to 2.2 mm and averaged 2 mm. Buccal shoulder finish line depth averaged 0.86 mm, and mean chamfer finish line depth was 0.74 mm lingually, 0.7 mm mesially, and 0.66 mm distally. The buccal shoulder for mandibular anterior teeth was significantly smaller than for other teeth and averaged only 0.45 mm. Conclusion: The mean convergence angle was clinically acceptable. However, shoulder depth was less than the recommended depth of 1.0 to 1.5 mm for metal ceramic crowns. Incisal/occlusal reduction was clinically adequate to provide enough structural durability and color matching.

This article describes a technique of constructing a set of maxillary and mandibular complete dentures in three visits instead of the usual five clinical appointments. This system of complete-denture construction is made possible because of the combined use of visible light-cured material as an impression tray and record base material, as well as the use of new biometric wax occlusion rims. Unlike some earlier techniques that use light-cured resin composites as the denture base materials, this method retains the use of heat-cured polymethylmethacrylate as the denture base material.

Air entrapment in the soft tissues of the cervicofacial region is a benign entity occasionally developing after a fracture of the facial bones or ribs. Characteristic clinical findings of air entrapment are the sudden onset of edema and crepitation of the respective region. Possible complications are respiratory obstruction or contamination of the mediastinum. Treatment includes precautionary administration of antibiotics. In regard to the region of injury, air may enter the anterior cranial fossa where it compresses the brain, resulting in pneumocephalus, which may cause meningitis as an imminent complication. After a fracture at the zygomatic or nasal bones, subcutaneous emphysema may result in the middle third of the face. It is also possible for air to penetrate into the retrobulbar fat and damage the eye. In other cases, air traverses the parapharyngeal space and causes pneumomediastinum. Moreover, after a fracture at the mandible, it is possible that air passes through the floor of the mouth and the submandibular area to the deep tissue layers again causing pneumomediastinum. Alternatively, after rib fracture, air could follow an upward course, resulting in subcutaneous emphysema of the thoracocervicofacial region. In this article, patients who suffered from air entrapment were categorized into four groups, and the methods used to diagnosis and treat these patients are presented.

Nerve injury can be related to mechanical, chemical, and thermal factors. Infection-related paresthesia is usually related to mechanical pressure and ischemia associated with the inflammatory process. Another cause of paresthesia could be the toxic metabolic products of bacteria or inflammatory products released following tissue damage. This article presents cases of inferior alveolar and mental nerve paresthesia caused by an infected impacted tooth, an infected cyst, and periapical infection. The possible pathophysiologic mechanism of nerve injury, therapy, and prognosis for recovery are also discussed.

Schizophrenia is a brain disease that manifests itself with multiple signs and symptoms involving thought, perception, emotion, and behavior. Despite the fact that these manifestations combine in various ways to create considerable diversity among patients, the cumulative effect of the illness is always severe and usually long lasting. Schizophrenia is diagnosed in the presence of certain positive and negative psychotic symptoms, as well as psychologic and cognitive deterioration. In addition to history, medical and psychiatric examinations are used to rule out other possible diagnoses. Schizophrenia is not a rare disorder, and it affects approximately 1% of the general population. Many of these individuals require several hospitalizations, and the financial cost of schizophrenia is substantial. In this article, clinical features of schizophrenia are reviewed, and the important consequences from the perspective of dental practitioners are highlighted.

Objective: To compare in vivo bitewing film quality using the holder versus the paper loop technique. Method and materials: Four bitewing films were taken from the right and left premolar and molar regions of 45 dental students using both the bitewing holder and paper loop techniques. A total of 360 films were taken and assessed by an experienced practitioner not apprised of the bitewing technique used. Of interest were: (1) the number of overlaps and the percentage of teeth showing the alveolar crest; (2) proper film positioning; and (3) the percentage of cone cutting. A Poisson regression using generalized estimating equations (GEEs) was used to estimate the difference in overlap between the two techniques. For proper positioning and cone cutting, logistic regressions using GEEs were used. Results: The average number of horizontal overlaps for the loop and holder techniques at the right premolar, right molar, left premolar, and left molar were 1.64, 2.11, 2.16, 2.78, and 1.64, 2.00, 2.00, 2.18, respectively. The loop technique was 1.11 times more likely to cause overlapping than the holder technique. The highest percentage of teeth showing the alveolar crest by the loop technique was 97.8% in the mandibular second premolar and first molar. With respect to film positioning, the loop technique was 1.12 times more likely to cause improper positioning than the holder technique. Both techniques demonstrated minimal cone cutting (1 in the loop versus 0 in the holder). Conclusion: The quality of bitewing films taken by the loop and holder techniques was not significantly different.

Objective: To evaluate and compare the sealability of root fillings in extracted teeth by using AH 26 and AH Plus in conjunction with three different obturation techniques. Method and materials: Root canals of 940 single-rooted teeth were prepared according to the crown-down/stepback technique (using both 2.5% NaOCl and File-Eze) before lateral condensation and hybrid condensation of gutta percha or obturation with Thermafil. Teeth were immersed in India ink for 90 hours after storage for 1 day, 1 week, 2 weeks, 1 month, and 6 months. The roots were split longitudinally, and the extent of dye penetration was measured using a stereomicroscope. Statistical analysis was performed using Kruskal-Wallis test and Mann-Whitney U test. Results: There were no statistically significant differences in apical leakage within the AH 26 and the AH Plus groups, nor between the two sealer groups, at any observation period. Coronal leakage was significantly higher for Thermafil compared to hybrid condensation at 1 day, 1 week, and 2 weeks both for AH 26 and AH Plus. Coronal leakage was higher only for Thermafil compared to lateral condensation at 1 week for AH 26 and for lateral condensation compared to hybrid condensation at 1 week for AH Plus. Conclusion: Both AH 26 and AH Plus, when used with an identical gutta-percha obturation technique, resulted in comparable sealability at all evaluation times and in comparable coronal sealability at 1 and 6 months.