Quintessence International, 02/2008

The endocrown is a restorative option for endodontically treated teeth. It consists of a circular butt-joint margin and a central retention cavity inside the pulp chamber and lacks intraradicular anchorage. This article describes the rationale and clinical guidelines for the placement of endocrowns. In the case presented, 2 old amalgam restorations on mandibular molars were replaced with endocrowns made of pressed ceramics (Empress 2, Ivoclar) following endodontic and periodontal therapy. A composite resin base was also used to fill undercuts and ensure a correct design of the preparations, contributing to significant tissue preservation. The postoperative situation shows the potential of this restorative approach to provide adequate function and esthetics, as well as biomechanical integrity of structurally compromised posterior nonvital teeth. It also prevents interferences with periodontal tissues, thanks to a supragingival position of the restoration margins. The foundation of this technique is to use the surface available in the pulpal chamber to assume the stability and retention of the restoration through adhesive procedures. Guidelines for the preparation, as well as the decision for omitting a post, are dictated by the amount of remaining coronal substance. This technique represents a promising and conservative alternative to full crowns for the treatment of posterior nonvital teeth that require long-term protection and stability. Keywords: adhesive posterior restoration, Empress 2, endocrown, nonvital teeth, pressed ceramics

Objective: To determine if patient ratings of their ability to chew are dependent on the method of complete denture fabrication. Method and Materials: Twenty edentulous patients participated in a randomized within-subject crossover trial. Each participant received 2 sets of new complete dentures. One pair (Gerber prosthesis) was manufactured based on tracings (to determine centric relation) and facebow transfer; semianatomic teeth with a lingualized and balanced occlusal pattern were used. The other set of complete dentures was made using a simplified procedure without facebow transfer; jaw relations were recorded with wax occlusion rims, and anatomic teeth were set with a canine and premolar guidance (Gysi prosthesis). The 2 dentures were delivered in randomized order, and each was worn for 3 months. Three months after insertion, patients' ratings of each new prosthesis were obtained on visual analog scales for general satisfaction, comfort, ability to speak, stability, esthetics, ease of cleaning, and ability to chew. Results: Patients rated their general satisfaction, stability, and esthetic appearance significantly better for the Gysi prostheses (P .05). No significant differences between the 2 denture treatment methods were detected for ability to speak, comfort, chewing ability, and the ease of cleaning the dentures. Conclusion: A comprehensive method for the fabrication of complete dentures using lingualized teeth does not appear to positively influence patient ratings of denture satisfaction when compared to a simple procedure with anatomic teeth. Keywords: complete denture, controlled clinical trial, facebow, lingualized occlusion, patient satisfaction, randomized controlled trial

Objective: The restoration of endodontically treated teeth has long been guided by empirical rather than biomechanical concepts. Part I of this literature review presented up-to-date knowledge about changes in tissue structure and properties following endodontic therapy, as well as the behavior of restored teeth in monotonic mechanical tests or finite element analysis. The aim of the second part is to review current knowledge about the various interfaces of restored, nonvital teeth and their behavior in fatigue and clinical studies. Review method: The basic search process included a systematic review of articles contained in the PubMed/Medline database, dating between 1990 and 2005, using single or combined key words to obtain the most comprehensive list of references; a perusal of the references of the references completed the review. Relevant information and conclusions: Nonvital teeth restored with composite resin or composite resin combined with fiber posts resisted fatigue tests and currently represent the best treatment option. In comparison to rigid metal and/or ceramic posts, when composite resin or composite resin/fiber posts fail, the occurrence of interfacial defects or severe tooth breakdown is less likely. Adhesion into the root, however, remains a challenge because of the unfavorable ovoid canal configuration, as well as critical dentin microstructure in the deepest parts of the canal. Thus, specific combinations of adhesives and cements are recommended. The clinical performance of post-and-core restorations proved satisfactory overall, in particular with a contemporary restorative approach using composite resin and fiber posts. However, the clinical literature does not clearly isolate or identify exact parameters critical to success. This, in turn, emphasizes the importance and relevance of in vitro studies to further improve the quality and long-term stability of prosthetic foundations. Keywords: clinical studies, fatigue, nonvital teeth, posts and cores, root adhesion

Gastroesophageal reflux disease (GERD) is a common disorder of the gastrointestinal tract in children and adults. The purpose of this report is to describe the case of a patient with GERD and the effects of the disease on the oral cavity, as well as to discuss functional and esthetic rehabilitation using composite resin. The authors also conducted a review of the literature on GERD etiopathogenesis, clinical signs and symptoms, diagnostic methods, and treatment. Keywords: dental erosion, gastroesophageal reflux disease, increase of vertical dimension of occlusion

The thyroid gland produces hormones critical to the maintenance of the cellular metabolic rate. The actions of these hormones are far-reaching, affecting thermoregulation and calorigenesis; the metabolism of carbohydrates, fats, and proteins; and oxygen utilization. Thyroid hormones also appear to act synergistically with epinephrine and enhance tissue sensitivity to catecholamines. Signs and symptoms of hypothyroidism include listlessness, fatigue, cold intolerance, dry skin, hair loss, constipation, weight gain, muscle soreness, and slow heart rate. Signs and symptoms of hyperthyroidism include irritability, heat intolerance, tremors, increased sweating, frequent bowel movements, and quickened heart rate. The effect of inadequately treated or undiagnosed hyperthyroidism on the heart carries perioperative risks. To provide competent dental care to patients with thyroid dysfunction, clinicians must understand the disease, its treatment, and the impact the disease and its treatment may have on the patient's ability to undergo and respond to dental care. Keywords: dental care, hyperthyroid, hypothyroid, thyroid dysfunction

Objectives: Because caries activity may be related to dental plaque acidogenicity, a method was developed for chairside evaluation of pH-lowering activity and lactic acid production by dental plaque. Moreover, this study examined the association of these 2 factors with caries experience on oral examination and with caries activity by following caries incidence for 4 years in a group of preschool children. Method and Materials: A dental plaque sample (2.4 µL) was collected from sound buccal surfaces of maxillary primary second molars using a spoon excavator and placed onto the sensor area of a portable pH meter. Sucrose (30 µL, 228 mmol) was mixed with the plaque sample, and pH changes were monitored for 10 minutes. After pH determination, lactic acid concentration in the plaque-sucrose mixture was measured using a portable lactate meter. Results: Caries experience of subjects correlated with minimum pH (at 10 minutes after sucrose addition) (r = -0.53, P .001) and lactic acid production (r = 0.38, P .001). In addition, increments of both primary tooth caries (?dft) and permanent tooth caries (?DFT) for 4 years correlated with minimum pH (r = -0.47, P .005 and r = -0.38, P .05, respectively). Setting cutoff values of pH and lactic acid concentration at 5.0 and 7.0 mmol/L for ?dft allows screening for caries-susceptible subjects (sensitivity = 0.950 and 0.800, specificity = 0.391 and 0.783, respectively). Conclusion: Plaque in caries-susceptible preschool children displays greater pH-lowering activity and lactic acid production. This method can be applied as a chairside screening test for caries activity and susceptibility for preschool children in dental clinics. Keywords: caries experience, caries incidence, chairside evaluation, dental plaque, lactic acid, pH

Objective: To compare the adherence of Prevotella melaninogenica and Enterococcus faecalis to 3 guided tissue regeneration membranes: Atrisorb, Lambone, and OsseoQuest. It was hypothesized that OsseoQuest would show increased bacterial adherence compared to Lambone and Atrisorb. Method and Materials: The barriers were suspended in trypticase soy broth containing an inoculum of either P melaninogenica or E faecalis. The samples were incubated under appropriate conditions for 6, 24, and 48 hours. Following incubation, each membrane was mixed in fresh media in a vortex machine to dislodge adherent bacteria. The vortexed media was quantitatively assessed using serial dilutions for viable cell count. Results: E faecalis exhibited higher adherence compared to P melaninogenica with time. Of the membranes tested, Lambone displayed the least bacterial adherence. Conclusion: An analysis of the results indicated that bacterial adherence was time-dependent for all membranes. Membrane structure, chemical configuration, hydrophobicity, and bacterial cell surface structure were suggested as factors contributing to variance in bacterial adherence. Keywords: bacteria, barrier membrane, periapical surgery

Objective: To review the recommendations by dental faculties regarding prophylactic removal of third molars (PR-3M) and to determine if the recommendations at institutions differed and whether there have been changes since 1998/99. Method and Materials: In 1998/99 and 2004/05, a questionnaire was sent to department chairpersons of oral surgery, orthodontics, and restorative dentistry/prosthodontics of US dental schools. They were asked to characterize their department's PR-3M recommendations for adolescents ( 21 years of age), young adults (21 to 35 years), and adults (> 35 years). Third molars were categorized as fully erupted, semierupted, and unerupted. Participants also were to indicate their rationale for PR-3M. Nonparametric and independent t tests were applied to the data (P = .05). Results: Response rates for 1998/99 and 2004/05 were 64% and 66%, respectively. There continues to be significant differences among the departments in PR-3M recommendations, especially for adolescents. There were fewer departmental differences for young adults and adults, with a majority recommending removal of semierupted and unerupted third molars for young adults. Of the chairpersons changing their recommendation, although not significant, more changed to remove than to retain. There was a significant decrease in recommendations to extract fully erupted third molars of young adults and adults. Nevertheless, recommendations to remove semierupted and unerupted third molars of adolescents and young adults remain high. Conclusions: The level of recommendations to electively remove third molars is inconsistent with the current nonintervention literature. Intramural departmental inconsistencies can result in confusion for students and patients. Hence, dental faculties may wish to reevaluate their curricula regarding third molar management. Keywords: department of orthodontics, department of oral surgery, department of prosthodontics, prophylactic extraction, third molars

Objective: To evaluate radiographically the prevalence of various types of root resorption in different tooth groups in a Middle Eastern population. Method and Materials: Full-mouth radiographs of 712 patients (19,072 teeth) were evaluated for the presence of root resorption. Two observers evaluated each tooth from at least 2 radiographic projections on periapical films. Results: Teeth exhibiting root resorption were found in 205 radiographs (28.8%). The most common form of resorption was pulpal infection (71.2%), mainly in mandibular molars (P .01) and in patients 45 years and older (P .005). Orthodontic pressure resorption was detected in 14.6% of root resorption cases, mainly in maxillary incisors (P .01). Impacted tooth or tumor pressure resorption was observed in 10.2% of all cases of resorption, mainly in mandibular molars (P .01), and periodontal infection resorption was identified in 3.9% of all resorption cases in all tooth groups (P > .05). Ankylotic resorption was not found in this survey. Conclusion: The most common types of root resorption in the general population were pulpal infection-related root resorption, orthodontic pressure root resorption, and impacted tooth pressure resorption. It is probable that most are unrelated to traumatic injuries of the teeth. Keywords: radiographic survey, root resorption

Objective: The use of antibiotics as an adjunctive therapy in the management of periodontal diseases has always been of interest for dental practitioners. Although studies have demonstrated the importance of different antibiotics as adjunct in the treatment of periodontitis, few studies have reported comparative results of antibiotics in localized aggressive periodontitis (LAP). The aim of the present study was to evaluate the comparative effects of systemic tetracycline derivative doxycycline versus a combination of metronidazole and amoxicillin in the elimination/suppression of Actinobacillus actinomycetemcomitans and their clinical effects during 90 days of follow-up in patients with LAP. Method and Materials: Thirty patients with untreated LAP participated in the study. Patients were randomly divided into 2 groups and given doxycycline or metronidazole plus amoxicillin, and periodontal clinical parameters were achieved at baseline and 10, 30, 60, and 90 days after microbiologic sampling. Patients were also given mechanical debridement after measurement at baseline. Results: Both groups of patients demonstrated improvement in clinical parameters, and microbiologic samples did not show any A actinomycetemcomitans at days 30, 60, and 90. Conclusion: Systemic use of doxycycline or metronidazole plus amoxicillin as an adjunct to conventional therapy may be used for the treatment of patients with LAP. Keywords: aggressive periodontitis, amoxicillin, doxycycline, metronidazole, therapeutic use

Objective: To compare the caries preventive effects of 2-year application of school-based chlorhexidine varnish, sodium fluoride gel, and dental health education programs among a high-risk group of 11- to 13-year-olds with low caries activity. Method and Materials: A total of 149 subjects who had previous caries experience in the primary dentition and Streptococcus mutans levels higher than 105 at baseline with 0 DMFS index were selected for this randomized clinical trial. Subjects were allocated to one of 3 groups for treatment with chlorhexidine varnish (n = 50), sodium fluoride gel (n = 50), or a dental health education program (n = 49), which were repeated throughout the 2-year study. The outcomes examined at the end of the study were the caries increment (DMFS index), dental plaque scores, and salivary S mutans counts. Results: The subjects in the education group showed a significant increase in the salivary levels of S mutans in comparison with the other groups (P = .004), but there was no significant difference among the groups in the caries increment after 2 years, with mean DMFS ± SD as 0.95 ± 1.33, 0.88 ± 1.47, and 1.05 ± 2.01 in the chlorhexidine varnish, sodium fluoride gel, and education groups, respectively. There were also no significant differences in the pre- and posttreatment plaque scores between the groups. Conclusion: Although all 3 preventive programs in this high-caries-risk group of children with low caries activity resulted in similar plaque and caries values after 2 years, longer follow-up studies are needed to clarify the effect of reduction in S mutans growth by chemotherapeutic agents in caries incidence. Keywords: caries, chlorhexidine, education, fluoride, Streptococcus mutans

Objective: To investigate oral Candida strain diversity in patients receiving radiation therapy for head and neck cancer compared to controls by conventional procedures, including cultivation of imprint samples on chromogenic medium and subsequent identification using Analytical Profile Index testing. Method and Materials: Twenty-two irradiated patients aged 18 to 55 years were recruited from the Maxillofacial Prosthetic Service, Mahidol University. Concomitantly, 22 healthy individuals whose age and sex matched that of the patient group were selected for a control group. Results: All patients studied were Candida carriers and were predominantly infected with Candida albicans (86.36%). Besides C albicans, other yeasts colonizing the oral cavity of these patients were C glabrata, C krusei, and C tropicalis. Candida carriage was found relatively less frequently (45.45%) in control subjects. However, C albicans was still the predominant species detected. No C dubliniensis was found in either group. Conclusion: Head and neck cancer patients who had received radiotherapy had a high prevalence of Candida colonization in the oral cavity. Consequently, prophylaxis to reduce Candida infection in these patients is required. This may improve the quality of life for patients who receive irradiation treatment for malignant cancer. Keywords: Candida, oral colonization, radiotherapy

Objective: To evaluate the resistance to fracture of endodontically treated teeth restored with combined composite-amalgam restorations in comparison to all-amalgam restorations. Method and Materials: Forty-eight human premolar teeth were equally divided into 4 groups. Mesio-occlusodistal (MOD) cavities were prepared in 3 groups, and in the fourth group, a modified MOD preparation was designed with an additional buccolingual groove. All teeth were endodontically treated and restored using 1 of several restorative modalities: all amalgam (AM), all amalgam plus dentin adhesive (ADA), amalgam plus dentin adhesive plus composite resin (ADAC), and amalgam plus dentin adhesive plus composite resin with a modified preparation design (ADACM). Specimens were tested in a universal testing machine (Instron). The load (in kilonewtons) at fracture was recorded and statistically analyzed using a Bonferroni one-way statistical analysis (significance: P = .01). Results: The teeth restored with a combined composite-amalgam restoration were significantly more resistant to fracture (P = .01) than teeth restored with amalgam alone. The modification with an additional horizontal buccolingual cavity preparation groove did not significantly increase resistance to fracture, nor did the addition of a bonding material to the amalgam restorations. Mean resistance to fracture (in kilonewtons) of each group was as follows: group AM, 0.31; group ADA, 0.34; group ADAC, 0.45; and group ADACM, 0.47. Conclusions: Restoration of endodontically treated teeth with combined composite-amalgam materials increased tooth resistance to fracture up to 51% when compared to teeth restored with amalgam alone. Keywords: composite-amalgam restorations, endodontically treated teeth, modified preparations, resistance to fracture

Objective: To assess different approaches to the dental management of lip injuries caused by self-inflicted oral trauma in 7 patients. Method and Materials: The patients were grouped based on 3 treatment approaches: group 1, placement of an oral appliance; group 2, botulinum toxin type A neuromuscular block; and group 3, oral surgery. Results and Conclusion: Neuromuscular block can be the first choice of treatment for patients with self-injurious behavior since botulinum toxin A injection is a well-tolerated, safe, and effective procedure, permitting improvement in muscle spasticity, bruxism, range of mouth opening, oral hygiene, and lip trauma. The second option would be the use of the oral appliance, and the last choice is oral surgery. Laser therapy was also found to be effective when applied to traumatic injuries in patients who present self-inflicted oral trauma. Keywords: botulinum toxin, lip trauma, oral appliances, self-injurious behavior, spasticity

Sodium hypochlorite (NaOCl) is currently used in the debridement and disinfection of the root canal system, supporting the mechanical procedures. Although it is considered a safe irrigant, the literature reports a few cases of adverse reaction caused by NaOCl: They range from injection through the apical foramen to air emphysema and allergic reactions as complications during endodontic treatment. The present report shows the possible severe clinical consequences of concentrated NaOCl extruding through the periapical tissues during root canal irrigation in a patient not allergic to NaOCl. Keywords: endodontic irrigants, hemorrhage, irrigation complications, skin patch tests, sodium hypochlorite, toxicity

Polymerization shrinkage of composite resins and the consequent stress generated at the composite-tooth interface continue to pose a serious clinical challenge. The development of high-intensity halogen lamps and the advent of curing units providing higher energy performance, such as laser lamps, plasma arc units, and, most recently, light-emitting diode (LED) curing units, have revolutionized polymerization lamp use and brought major changes in light-application techniques. A comprehensive review of the literature yielded the following conclusions: (1) the most reliable curing unit for any type of composite resin is the high-density halogen lamp, fitted with a programming device to enable both pulse-delay and soft-start techniques; (2) if any other type of curing unit is used, information must be available on the compatibility of the unit with the composite materials to be used; (3) polymerization lamp manufacturers need to focus on the ongoing development of LED technology; (4) further research is required to identify the most reliable light-application techniques. Keywords: curing units, diodes, halogen, laser, light, plasma, pulse delay, soft start

Objective: To investigate the quality of root canal fillings and coronal restorations in relation to periapical status in a Greek population. Method and Materials: A total of 320 patients who required full-mouth radiographic examination were included. The quality of root canal fillings and the periapical status, as well as the quality of coronal restorations, were assessed by radiographic criteria. Results were analyzed using random effects logistic regression models. Results: Root canals with adequate filling length had a lower incidence of apical periodontitis than root canals with inadequate filling length (51.7% versus 63.4%, P = .002). Root-filled canals with adequate coronal restorations showed a lower incidence of apical periodontitis than those with inadequate restorations (47.3% versus 67.4%, P .001). When both root filling and coronal restoration were assessed, the incidence of apical periodontitis ranged from 39.2% to 67.6%. Conclusion: Quality of root canal treatment, as well as quality of coronal restoration, are strongly associated with the incidence of apical periodontitis. Keywords: apical periodontitis, coronal restoration, epidemiologic study, Greek population, radiographic criteria, root canal filling