Quintessence International, 02/2007

Gingival squamous cell carcinoma represents less than 10% of diagnosed intraoral carcinoma. Many unique features of gingival squamous cell carcinoma clearly delineate it from oral squamous cell carcinoma arising in other sites. This article presents the clinicopathologic findings of a case. An 81-year-old woman presented for evaluation of multiple oral lesions primarily limited to the maxillary gingiva; the lesions had been present for about 2 years. Differential diagnosis included epithelial dysplasia, benign mucous membrane pemphigoid, inflammatory lesion of endodontic/periodontic origin, lichen planus, and squamous cell carcinoma. Clinical examination revealed extensive erythematous and ulcerative lesions of maxillary buccal and palatal gingiva extending into the maxillary buccal vestibule; the lesions did not respond to antibiotic therapy. Radiographic evaluation demonstrated advanced alveolar bone loss as well as displacement of the maxillary right first molar. Subsequent histology confirmed diagnosis of moderately differentiated squamous cell carcinoma. Gingival squamous cell carcinoma can mimic a multitude of oral lesions, especially those of inflammatory origin. In addition, predisposing and presenting factors are different from those of other oral squamous cell carcinomas. Careful examinations as well as routine biopsy are crucial for accurate diagnosis. Keywords: carcinoma, gingiva, periodontal disease, squamous cell carcinoma

Objective: To identify the clinicopathologic features of epulides in West China and to compare these data with those of previous studies from other countries. Method and Materials: Demographics; clinical data including gender, age, and chief complaints of the patients; and the type, size and location, duration, diagnosis, and histologic features of the lesion were studied from among biopsy specimens and clinical records at West China College of Stomatology from January 1951 to July 2005. Results: A total of 2,439 epulides were identified. Epulides found were peripheral fibroma (PF: 1,489, 61.05%), peripheral ossifying fibroma (POF: 431, 17.67%), pyogenic granuloma (PG: 482, 19.76%), and peripheral giant cell granuloma (PGCG: 37, 1.52%). The total ratio of males to females was 1:1.40. Specifically, the ratios were 1:1.31 for PF, 1:1.99 for PG, and 1:1.47 for PGCG (all P .001). The peak incidence of epulides fell in the third to sixth decade of life overall, the fifth to sixth decade for PF and POF, and the third to fourth decade for PG. Conclusions: Among the 4 kinds of reactive lesions, PF had the highest incidence and PG had the lowest incidence in Chinese patients. There were also differences in type, sex, age, location, duration, and histologic features: PF was the most common type; all of the epulides except PGCG showed a predilection for females; PG was more prevalent among young patients; and POF lasted much longer than other lesions. Differences in the distribution of the 4 types of lesion were also found among various ethnic groups. Keywords: giant cell granuloma, gingival disease, gingival hyperplasia, pyogenic granuloma, retrospective study

Objective: To collect, retrospectively, long-term results from patients who received immediately loaded Straumann implants with bar-retained overdentures. Method and Materials: The surgical and prosthetic treatment took place between 1981 and 1991 at the Department of Oral Surgery, Oral Radiology, and Oral Medicine, University of Basel. In each case on the day of the operation, the patients were fitted with a bar that was immediately loaded with a hybrid prosthesis. Patients who were available at the time of this study were clinically reexamined and statistically assessed. Results: Among the 44 patients who received 176 interforaminal Straumann implants (4 implants per patient), follow-up was possible in 23 patients, who had received a total of 89 implants. The mean observation time for the implants was 12.2 years (8 to 18 years). Three implants were lost. Five implants did not meet the predetermined success criteria. Using the definition by Cutler and Ederer, the probability of success was 83.3%. Conclusions: The results show that the requisite 4-month healing time for immediately loaded interforaminal Straumann implants with bars does not have to be observed. Keywords: immediate bar, immediate loading, implants, long-term results, overdenture

Objectives: To investigate the effects of pretreatment (silanization) on bond strengths between 3 different types of fiber posts and 4 resin cements, respectively. Method and Materials: Prefabricated quartz-fiber (Unicore Post, Ultradent) and prefabricated glass-fiber (FRC Postec, Ivoclar Vivadent) posts with a cross-linked polymer matrix and individually formed glass-fiber posts with an interpenetrating polymer network (IPN Post, Stick Tech) (n = 160 each) were inserted into resin composite disks (2 mm thick) using the following resin cements and silane solutions: Panavia F/Porcelain Bond Activator (Kuraray), PermaFlo DC/Silane (Ultradent), Variolink II/Monobond S (Ivoclar Vivadent) and RelyX Unicem/Espe Sil (3M Espe). Nonsilanated posts served as controls. The push-out bond strengths were determined before (n = 10) and after (n = 10) thermocycling (2,000 cycles, 5°C to 55°C, dwelling time 30 seconds). Results: Bond strengths (mean [SD]) were significantly affected by the resin cement (P .001), the pretreatment (P .001), and the type of post (P .001), but not by thermocycling (P = .955, 4-way ANOVA). The IPN post demonstrated significantly higher bond strengths compared to the other posts (P .05; Tukey B). Silanization significantly increased bond strengths (15.2 [5.2] MPa) compared to those of the control groups (13.9 [4.9] MPa). Conclusion: The type of fiber post revealed a significant influence on bond strengths, whereas the effects of silanization appeared to be clinically negligible. Keywords: fiber post, push-out bond strengths, silane, thermocycling

Objective: To define the reproducibility and accuracy of the Prepometer device (Hager & Werken) and to correlate the measured electrical resistance with the remaining dentin thickness. Method and Materials: In vivo standardized cavities were made on the buccal side in the cervical region of 12 intact teeth. Measurements with the Prepometer were completed before tooth extraction. After extraction, in vitro measurements of the remaining dentin thickness were performed using a µfocus-computerized tomography scanner. These in vitro scan data were compared with the in vivo measurements, and correlation coefficients calculated. The intra- and interinvestigator variability were defined, using a paired 2-tailed Student t test. The level of significance was set at 5%. Results: Although both the intra- and interinvestigator variability scored well, there was no clear correlation between the Prepometer measurements and the remaining dentin thickness. Because the device determines the electrical resistance of the dentin, which is related to dentin permeability, real remaining dentin thickness cannot be measured. A reasonable safety zone (3 of 12 teeth scored false negative and 1 of 12 teeth scored false positive) in terms of remaining dentin thickness was observed. Conclusions: The Prepometer, a device developed to screen dentin-surface permeability by measuring its electrical resistance, was shown to be reproducible in its use. However, electrical resistance was shown not to correlate with dentin thickness. Although the Prepometer might help to estimate the risk of pulp injury after tooth preparation, its effectiveness still remains to be proven in a randomized clinical trial. Keywords: dentin permeability, dentin thickness, microcomputerized tomography, Prepometer, pulp injury, tooth preparation

Objective: To determine the current prevalence and severity of caries in primary dentition in a preschool population in 2 provinces in China, and to investigate the relationship between caries experience and sociodemographic factors, parental characteristics, dietary habits, and oral hygiene practice. Method and Materials: A cross-sectional survey was conducted on a representative sample of Chinese preschool children aged 3 to 5 years. Clinical examinations were carried out on 2,014 children using the method and criteria established by the World Health Organization. Structured questionnaires for information related to the sociodemographic background, oral hygiene practices, and dietary habits of the children were completed by their mothers. Results: Overall, 45% of children were caries free, and 14% had rampant caries. The mean dmft and dmfs values were 2.57 and 4.25, respectively. The caries prevalence and severity increased with age. The children from rural areas brushed their teeth less regularly and had a higher level of caries experience than those from urban areas. Significant predictors of caries experience were location, area, age, mother's education level, and consumption of fruit juice from a feeding bottle. Conclusions: These data indicate that a high proportion of young Chinese children had dental caries and that most decayed teeth were left untreated. The prevalence and severity of caries was associated with socioeconomic status and dietary factors in this sample of children. Keywords: caries, dietary habit, oral hygiene, rampant caries, social class

Objective: To evaluate the effect of artificial aging on the fracture strength and stiffness of fiber-reinforced composite fixed partial dentures (FPDs). Method and Materials: Twelve FPDs were replicated using Targis/Vectris resin composite (Ivoclar Vivadent) and randomly divided in 2 groups. Group A was artificially aged for 900 hours in a weathering machine using dry/wet cycles and 534 W/m2 irradiations with wavelengths ranging from 300 to 800 nm. Group B (control) was stored in 100% relative humidity at 37°C ± 1°C for 900 hours. The FPDs were luted on metal abutments with Variolink II resin cement (Ivoclar Vivadent). The flexure stress was applied on the pontic at a descending speed of 1.0 mm/min until complete failure. Fracture strength, stiffness, and number of cracks produced on the FPDs were statistically analyzed. Results: Targis veneering material in the control group fractured at a mean of 913 ± 130 N, whereas in the aged group it failed at a mean of 722 ± 154 N (P = .042). The mean fracture load of aged FPD frameworks was slightly lower than that of the controls: 1,532 ± 237 N and 1,578 ± 257 N, respectively (P = .758). The stiffness at 400 N was not significantly different between the 2 groups. The number of cracks at Targis failure was higher in aged groups. Conclusion: Accelerated aging significantly reduced the strength of the Targis veneering composite, increasing its brittleness; however, it had no effect on the inner Vectris framework. Keywords: accelerated aging, fiber-reinforced composites, fixed partial dentures, flexural strength, metal-free restorations, polymer degradation

Plasmablastic lymphoma is a rare subcategory of non-Hodgkin lymphoma frequently associated with human immunodeficiency virus. It is a large B-cell lymphoma that has a predilection for the oral cavity. Clinically, plasmablastic lymphoma may mislead to a diagnosis of Kaposi's sarcoma. When infected, plasmablastic lymphoma may mimic an odontogenic cellulitis. Epstein-Barr virus and human herpesvirus 8 are very often associated. Awareness of this entity can prevent misdiagnosis with nonlymphoid malignancies, notably Kaposi's sarcoma, because this lesion does not express the conventional B-cell markers. Unfortunately, as for other high-grade lymphomas in patients with acquired immunodeficiency syndrome (AIDS), the prognosis is poor. The case of a heterosexual 42-year-old man referred for a right hemifacial neoplasm is reported. Keywords: Epstein-Barr virus, human herpesvirus 8, human immunodeficiency virus (HIV), non-Hodgkin lymphoma, plasmablastic lymphoma, oral cavity

Objective: To evaluate the pulp response to direct capping with self-etching adhesive systems using sodium hypochlorite as a hemostatic agent. Method and Materials: Twenty-six human third molars scheduled for extraction were selected from undergraduate students of dentistry. Class I cavities with pulp exposures were performed. To control bleeding, 2.5% sodium hypochlorite was used for 20 seconds, followed by washing with saline solution. The pulp exposures were capped with calcium hydroxide (n = 10) or adhesive system (n = 16). All cavities were restored with adhesive system and composite resin. Half of the samples of each capping material were extracted after 30 days and the remaining after 90 days. The samples were prepared for histological analysis (hematoxylin-eosin) and bacterial detection (Brown & Hopps) and evaluated according to standard ranking. Data were submitted to statistical analysis (Mann-Whitney test). Results: There was a significant difference (P .05) only in relation to dentin barrier formation. Pulps dressed with calcium hydroxide showed dentin barrier formation in all specimens, obliterating the exposure site. No inflammatory response was associated with material. In the experimental group, after 30 days, there was an attempt for healing with reparative dentin deposition, presenting a mild to moderate inflammatory infiltrate. Similar findings were found after 90 days, decreasing the inflammatory response. Bacteria were not detected in any specimen evaluated. Sodium hypochlorite was effective for hemostatic control. Conclusion: Calcium hydroxide produced better biological performance than the self-etching adhesive, and sodium hypochlorite did not interfere with the pulp repair. Keywords: calcium hydroxide, composite resin, dentin barrier, dentin-bonding agent, pulp capping, sodium hypochlorite

Objective: The aim of the study was to evaluate the pure titanium castability and internal porosity with 3 different sprue designs. Method and Materials: The sprue designs selected were the conventional cylindrical, funnel-shaped, and sheet-form sprue formers. To evaluate the castability, the mesh monitor was chosen. Eight mesh patterns (14 3 14 mm) of 49 squares were attached to each type of sprue design. They were invested in titanium investment material and cast in a semiautomatic titanium casting machine. The titanium castings were evaluated by 2 methods. One was the visual observation of the castings for completeness, and the second was the radiographic qualitative analysis for the location of the internal porosities. Results: Data were analyzed with analysis of variance and Student t test for paired comparison among different sprue designs. According to analysis of variance, all sprue designs revealed a statistically significant difference at the 5% level of confidence (P .05, F = 3.50). Mesh patterns attached to funnel-shaped sprue designs showed better percentage castability values. Conclusion: For titanium, casting using a funnel-shaped sprue design displayed better castability values and less internal porosities in the castings. Keywords: dental casting, porosity, sprue design, titanium castability

Objective: The purpose of this in vitro study was to evaluate the effects of 10% carbamide peroxide (Vivastyle/Vivadent) and 6.5% hydrogen peroxide strip bands (Crest Professional Whitestrips) on the surface roughness and hardness of the 3 different tooth-colored restoratives: an ormocer (Definite), a packable composite (Filtek P60), and a flowable composite (Filtek Flow). Method and Materials: A total of 48 specimens (10 mm in diameter and 2 mm thick) of each material were fabricated against a mylar surface. After being polished with Sof-Lex discs, they were randomly divided into 3 groups of 16 and treated as follows: group I was stored in distilled water at 37°C for 2 weeks (control), group II was treated with Vivastyle for 2 hours per day for 2 weeks, and group III was treated with Whitestrips for 30 minutes twice a day for 2 weeks. For groups II and III, the specimens were stored in distilled water at 37°C during the hiatus period. At the end of the test period, the specimens were first subjected to surface roughness and then to microhardness tests. The data were analyzed by Kruskal-Wallis and Mann-Whitney U tests. Results: Both bleaching regimens increased the surface roughness of the materials (P .05), but Whitestrips significantly increased the roughness of materials more than did Vivastyle (P .05). Both bleaching regimens decreased significantly the hardness of tested materials except Filtek P60 (P .05). Conclusion: Bleaching agents may affect the surface of existing restorations; therefore, they should not be used indiscriminately when tooth-colored restorations are present. Keywords: bleaching, hardness, roughness, tooth-colored restorative materials

IIntravascular papillary endothelial hyperplasia (IPEH) is an unusual, benign, non-neoplastic, vascular lesion characterized histologically by papillary fronds lined by proliferating endothe-lium. Osteoma is a benign osteogenic lesion characterized by proliferation of compact or cancellous bone. Osteoma of the maxillary sinus is an uncommon lesion. The purpose of this report is to present a case with 2 different lesions (intravascular papillary endothelial hyperplasia and osteoma) occurring at the same time in 1 patient that may or may not be related to each other and to stress the value of diagnostic imaging. Keywords: computed tomography, intravascular papillary endothelial hyperplasia, magnetic resonance imaging, osteoma

Objectives: Impression techniques in restorative dentistry require displacement of gingival tissues to expose subgingival finish lines on tooth preparations. Retraction cords are commonly used for this purpose. Some cord systems include various medicaments, which may remain in the sulcus after retraction procedures. The purpose of this study was to determine whether any of the commonly used gingival retraction medicaments could influence the surface characteristics of the impression material and to evaluate the clinical performance of retraction cords. Method and Materials: Sixteen cord systems in various shapes, sizes, and medications were used in this study. The clinical performances of cords were evaluated with a blind experimental study design, according to predetermined criteria. Results were analyzed by using chi-square test and ordinal logistic regression analysis (P .05). Results: Statistically significant differences were found in all criteria among groups (P .05). None of the materials investigated appeared to have any influence on the surface characterization of the polyvinyl siloxane impression material used. Better impression qualities were observed in groups with easy insertion, proper dilatation, less recurrent bleeding, and no remnants or fraying. Logistic regression analysis revealed that both retraction cord medicaments (odds ratio = 0.63, P = .00 .05) and cord thicknesses (odds ratio = 2.09, P = .00 .05) were important risk factors on the gingival margin quality. Conclusions: The applied gingival retraction cord systems had no influence on the surface characterization of the polyvinyl siloxane material tested. Gingival margin quality of the impression and clinical application procedures were affected by the retraction systems. Untreated, medium-braided, and epinephrine-impregnated cord systems were clinically successful. However, the potential systemic effects of epinephrine must be considered. Keywords: medicament, polyvinyl siloxane, retraction cord

Sealing of incipient carious lesions in occlusal surfaces has been shown to arrest the progression of the lesions. In this report, we describe for approximal surfaces with noncavitated incipient lesions the clinical procedures for sealant application illustrating this minimally invasive method with 3 clinical cases and scanning electron microscopic images. Keywords: approximal carious lesions, case reports, minimally invasive method, pit and fissure sealant

Objective: To portray and assess the interfacial morphology achieved with self-etching systems in dentin under observation by scanning electron microscopy. Method and Materials: Ten caries-free extracted erupted human third molars were used in this study. The occlusal enamel was removed, and 10 dentin disks with a thickness of 800 ± 200 µm were obtained by slow-speed sectioning with a diamond saw parallel to the occlusal surface. A standard smear layer was created on the occlusal surface by wet sanding with 600-grit sandpaper for 60 seconds. The dentin disks were randomly assigned to one of the systems: AdheSE (Ivoclar Vivadent), Optibond Solo Plus-Self-Etch (Kerr), Tyrian SPE (Bisco) as self-etching primers, and Adper Prompt Self-Etch (3M Espe) and One-Up Bond F (Tokuyama) as self-etching adhesives. All systems were applied according to the manufacturers' instructions. After application of the adhesive systems, a 1.0-mm-thick layer of a flowable composite resin (Filtek Flow; 3M Espe) was applied to the treated dentin surface and light cured for 40 seconds. The specimens were then processed for observation by scanning electron microscopy. Results: All self-etching systems achieved the formation of sealed interfaces and hybridized areas with variable extents except for the self-etching adhesive One-Up Bond F, which showed some gap formation and poor hybridization. Optibond Solo Plus-Self-Etch presented a more consistent adhesive interface with thicker hybrid layers, numerous resin tags, and lateral branches. Conclusion: Regarding the micromorphology aspect, Optibond Solo Plus-Self-Etch showed the finest result, while One-Up Bond F was not able to produce a satisfactory ultrastructural morphology. Keywords: adhesive, dentin, hybrid layer, interfacial morphology, scanning electron microscopy, self-etching primers

Endodontically treated teeth are commonly required to serve as abutments for crowns, fixed partial dentures, or removable partial dentures. Many clinicians are of the opinion that endodontically treated teeth do not serve as well as vital teeth. This article reviews the pertinent literature and seeks to reach a consensus for the use of endodontically treated teeth with each type of prosthesis. With appropriate preparation designs, endodontically treated teeth can serve well as abutments for crowns. As restorations become more complex and involve edentulous spans, some reservations apply. In some fixed partial denture designs, the use of endodontically treated teeth may be contraindicated. Keywords: crowns, dental abutment, endodontically treated teeth, fixed partial dentures, removable partial dentures

Dens in dente is a developmental anomaly that predisposes the tooth to develop caries and pulp periapical pathologies. A chronic lesion can develop without any clinical symptoms of the pathology. The purpose of this case report is to decribe the endodontic treatment of dens in dente associated with a periapical lesion using a mineral trioxide aggregate apical plug. Keywords: apical plug, dens in dente, endodontic treatment, healing, mineral trioxide aggregate, periapical lesion

Objectives: The objective of this study was to assess the resistance to fracture of crowned endodontically treated premolars with varying ceramic and metal post systems under simulated occlusal load. Method and Materials: The study consisted of 60 extracted intact premolars with similar root diameter and length. Teeth were divided equally into 4 groups (n = 15) and prepared for posts and cast crowns as follows: group 1 = preformed metal post, composite core, and cast crown; group 2 = cast post and core and cast crown; group 3 = zirconia post, composite core, and cast crown; and group 4 = zirconia post and heat-pressed ceramic core and cast crown. All prepared teeth had 2 mm of sound dentin on which the cast crowns were cemented. A continuous load (kg) was applied by an Instron testing machine to the buccal cusp at a 30-degree angle to the long axis of each tooth at a crosshead speed of 2 mm/min until failure. One-way analysis of variance with Scheffé test was used to statistically compare the differences between groups. Results: Mean failure loads (in newtons) for the 4 test groups were as follows: 1,103.3 (group 1), 1,234.5 (group 2), 826.6 (group 3), and 870.6 (group 4). No significant difference in failure load values was found among all tested groups (F[3,59] = 2.05; P > .05). The primary mode of failure (85%) in all groups was an oblique radicular fracture, either apical to the post or at the post level. Horizontal fracture (15% to 20%) of the root and post was found in groups 3 and 4. Conclusion: Within the limitations of this study, varying ceramic and metal post systems did not affect the failure resistance of teeth restored with full-coverage cast metal crowns, under simulated occlusal load. Keywords: ceramic post, premolars, resistance to fracture

Objectives: Despite the broad use of occlusal splints in the treatment of temporomandibular disorders, the efficacy of splints is a source of controversy. In this study, the effectiveness of occlusal splints on the electromyographic activity of the masseter and temporal muscles in healthy individuals was investigated. Method and Materials: An occlusal splint was made for 25 healthy individuals. Surface electromyographic recordings were done during maximum clenching without the splint and immediately after application of the splint. The relative level of activity in the masseter and temporal muscles was quantified by means of activity index. Paired t test and Wilcoxon signed-rank tests were used for data analysis. Results: The mean electromyographic activities of masseter and temporal muscles (in mV/s) were 0.7712 and 1.0488 without the splint and 0.8396 and 0.9276 immediately after application of the splint. There was no significant difference between the electromyographic activities of both muscles before and after insertion of the splints. The activity index increased after application of the occlusal splints. This increase was also insignificant. Conclusion: Immediate application of occlusal splints has no significant effect on the activity of masseter and temporal muscles. It could decrease the relative activity of the temporal to the masseter muscle (increasing the activity index). Keywords: electromyography, masseter physiology, maximum clenching, muscle physiology, occlusal splint, temporal physiology