Detection of Horizontal Root Fracture with Small-volume Cone-Beam Computed Tomography in the Presence and Absence of Intracanal Metallic Post

Introduction: The aim of the present study was to test the accuracy of small-volume cone-beam computed tomography (CBCT) scanning in the detection of horizontal root fractures and to assess the influence of a metallic post. Methods: Forty teeth were divided into four groups based on the presence of metallic posts and horizontal root fracture. The teeth were examined by small-volume CBCT scanning at 0.2-mm voxel resolution. Three observers analyzed the samples for the presence of a horizontal root fracture. Sensitivity and specificity were calculated. Results: High values for accuracy (73%-88%) were obtained in the groups without a metallic post, and statistically significant differences were found when the group with a metallic post has been observed (55%-70%). Intraobserver agreement also showed statistically significant differences in the groups with a metallic post. Conclusions: Small-volume CBCT scanning showed high accuracy in detecting horizontal root fracture without a metallic post. However, the presence of a metallic post significantly reduced the specificity and sensitivity of this examination. (J Endod 2011;37:1456-1459)

Tooth Tissue Engineering: Optimal Dental Stem Cell Harvest Based on Tooth Development

Our long-term objective is to devise reliable methods to generate biological replacement teeth exhibiting the physical properties and functions of naturally formed human teeth. Previously, we demonstrated the successful use of tissue engineering approaches to generate small, bioengineered tooth crowns from harvested pig and rat postnatal dental stem cells (DSCs). To facilitate characterizations of human DSCs, we have developed a novel radiographic staging system to accurately correlate human third molar tooth developmental stage with anticipated harvested DSC yield. Our results demonstrated that DSC yields were higher in less developed teeth (Stages 1 and 2), and lower in more developed teeth (Stages 3, 4, and 5). The greatest cell yields and colony-forming units (CFUs) capability was obtained from Stages 1 and 2 tooth dental pulp. We conclude that radiographic developmental staging can be used to accurately assess the utility of harvested human teeth for future dental tissue engineering applications.

Periodontal disease in adults with untreated congenital growth hormone deficiency: a case-control study

P>Aim The aim of this study was to investigate the possible associations between isolated growth hormone deficiency (IGHD) and periodontal attachment loss (PAL) in adults affected by congenital IGHD. Materials and methods Forty-five previously identified IGHD subjects were eligible for this study. The final study sample comprised 32 cases (gender:20M/12F; age:44.8 +/- 17.5) matched for age, gender, diabetes, smoking status and income to 32 controls (non-IGHD subjects). Participants were submitted to a full-mouth clinical examination of six sites per tooth and were interviewed using a structured, written questionnaire. Periodontitis was defined as proximal PAL >= 5 mm affecting >= 30% of teeth. Results No significant differences were observed in the percentage of sites with visible plaque between IGHD and non-IGHD subjects (59.4% versus 46.9%, p=0.32). IGHD subjects had significant less supragingival calculus (31.3% versus 59.4%, p=0.02) and more bleeding on probing (71.9% versus 18.8%, p < 0.01) than controls. PAL >= 5 mm was significantly more prevalent (100% versus 71.9%, p < 0.01) and affected more teeth (30.5% versus 6.7%, p < 0.01) in cases than in controls. After adjusting for supragingival calculus, IGHD cases had a higher likelihood of having periodontitis than controls (OR=17.4-17.8, 95% CI=2.3-134.9, p=0.004-0.005). Conclusion Congenital IGHD subjects have a greater chance of having PAL.

Cigarette smoke inhalation modulates gene expression in sites of bone healing: a study in rats

Objective. The aim of this study was to assess the effect of cigarette smoke inhalation (CSI) on gene expression in alveolar bone healing sites. Study design. Wistar rats were randomly assigned to the groups: control [animals not exposed to CSI (n = 20)] and test [animals exposed to CSI, starting 3 days before teeth extraction and maintained until killing them (n = 20)]. First mandibular molars were bilaterally extracted, and the expression of alkaline phosphatase, bone morphogenetic protein (BMP) 2 and 7, receptor activator of nuclear factor kappa B ligand, osteoprotegerin, and d2 isoform of vacuolar adenosine triphosphatase V(o) domain were assessed by quantitative polymerase chain reaction in the newly formed tissue in the sockets. Results. Overall, data analysis demonstrated that CSI significantly affected the expression pattern of all of the studied genes except BMP-7. Conclusion. The expression of key genes for bone healing may be affected by CSI in tooth extraction sites. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:447-452)

Implant-supported prosthesis following Branemark protocol on electromyography of masticatory muscles

This research evaluated the effects of Branemark protocol on electromyography of the masseter and temporal muscles. The patients were divided into two groups: Group 1: patients who wore an implant-supported prosthesis in the mandibular arch following Branemark protocol, and maxillary removable complete dentures; Group II: dentate individuals (control). Electromyography was carried out at rest, right (RL) and left (LL) laterality, protrusion and maximum voluntary contraction (MVC). Data were compared by t-test. At rest, a higher electromyographic (EMG) activity was observed in Group I, and the values were significant in the right masseter and left temporal muscles. In RL, there were statistically significant differences for right masseter (P < 0.01), left masseter and temporal muscles and for the left temporal muscle in LL (P < 0.05). In protrusion, Group I presented a higher EMG activity, and there was a statistically significant difference for the right masseter muscle (RM) (P < 0.05). In MVC, the EMG values were higher in Group II (control), but significant just for the right temporal muscle (P < 0.05). In conclusion, individuals with mandibular fixed dentures supported according to the Branemark protocol and maxillary removable complete dentures showed a higher activity of masticatory muscles during the mandibular postural clinical conditions examined; however, in the MVC, Group I presented lower values when compared to dentate group. Despite presenting different EMG values in all of the clinical conditions, both groups showed similar EMG patterns of muscle activation which demonstrates that the proposed treatment can be considered as a good option for oral rehabilitation.

Oral status and Candida colonization in patients with Sjogren`s Syndrome

Objective: To determine the oral status, salivary flow rate, Candida carriage in saliva, and prevalence of Candida albicans colonization in several areas of the mouth in patients with primary and secondary Sjogren`s syndrome as opposed to those of healthy subjects. Study design: Thirty-seven patients with Sjogren`s syndrome (SS), [14 patients with primary SS (SS-1) and 23 patients with secondary SS (SS-2)], along with 37 healthy controls were examined in regard to number of teeth, pro-bing pocket depth (PPD), approximal plaque index (API), bleeding on probing (BOP), presence of prosthetic appliances and smoking habits. Salivary flow rate (SFR), Candida carriage in saliva, presence of Candida albicans colonization on buccal, angular, palatal and sulcular areas, on dentures and on the tongue`s dorsal surface were determined. Statistical analyses were performed using the 2-tailed Fisher exact and Kruskal-Wallis test. Results: No statistically significant difference was found between SS-1 and SS-2 groups based on the parameters analysed. Statistically significant differences were observed between patients with SS and healthy subjects in terms of SFR, oral signs and symptoms, API, BOP, C. albicans colonization on tongue and buccal area, and Candida carriage in saliva. In the gingival crevicular fluid positive C. albicans colonization was found in only one subject of SS subgroup. Conclusions: SS patients carry a higher risk of having periodontitis and are more predisposed to develop candidiasis. C. albicans is scarcely detected in gingival crevicular fluid despite high scores on C. albicans colonization in different areas of the oral cavity in SS patients.

Tooth loss prevalence and risk indicators in an isolated population of Brazil

Objective. The aim of this study was to assess the prevalence, extent, and risk indicators of tooth loss in an isolated population of Brazil. Material and methods. Two-hundred-and-forty-two subjects, ranging in age from 14 to 82 years (mean 36.2 years), were identified by census in an isolated population of Brazil. All consenting subjects received a full-mouth clinical (DFT index and information about missing teeth) and periodontal examination of 6 sites per tooth. Furthermore, they were interviewed using a structured written questionnaire in order to gather information about demographic, environmental, and biological variables. Results. Of the 200 subjects (80% response rate), 19 (9.5%) were edentulous, 90% had lost at least one tooth, and 39% had lost more than 8 teeth. The mean number of teeth lost was 9.5 (95% CI = 8.2-10.8). First mandibular molars were the most commonly missing teeth. In a multiple logistic regression analysis based on a theoretical hierarchical model of tooth loss, having more than 8 teeth lost was strongly associated with adult age (OR = 18.3-17.3, 95% CIs = 4.8-69.7 and 4.0-75.1) and female gender (OR = 5.9, 95% CI = 1.9-18.2) in the final model. Conclusions. Tooth loss was highly prevalent and extensive in this isolated population. Demographic and behavioral factors played an important role in tooth loss prevalence in this population.

Nasopharyngeal angiofibroma. surgical approach using a transoral Le Fort I osteotomy following embolization: a case report

Nasopharyngeal angiofibroma (NA) is a rare vascular benign nonencapsulated neoplasm, characterized by local aggressiveness and destructive potential, typically diagnosed in adolescent males. We report a case of NA affecting a 15-year-old male that presented with a persistent nasal obstruction and epistaxis with 1 year of evolution. Clinical and radiological patterns pointed out a differential diagnosis of NA. Arteriography demonstrates the vascular support of the tumor and evinces the embolization of the internal maxillary artery. The surgical approach was procedure by Le Fort I osteotomy exposing the tumor and promoting easy access for posterior removal. The surgery was carried out without hemorrhagic problems. The maxilla was fixed in the original position with 4 L-shape plaques. Histopathological findings supported the diagnosis of NA. The patient presented after 8 months of postoperative follow-up, without clinical signs of recurrence or residual tumor and without palatal or maxillary teeth paresthesia.

Early dental plaque formation on toothbrushed titanium implant surfaces

Purpose: To evaluate the qualitative and quantitative differences on dental plaque formation on two different roughness titanium implant surfaces, i.e. machined and titanium plasma sprayed, as well as the amount of plaque removal by regular toothbrushing after 72-hour plaque accumulation. Methods: Eight systemically healthy subjects were recruited from the patient pool of a private dental practice. All patients underwent oral hygiene instruction and full mouth prophylaxis. Subsequently, maxillary casts from all patients were obtained and removable 0.7 mm-thick acetate stents without occlusal contact points were fabricated to support four titanium specimens of 4x2x2 mm divided into two groups (machined and plasma sprayed). Subjects were instructed to wear the stents for 72 hours, full time, removing them only during regular oral hygiene. Subsequently, the appliances were immediately repositioned and then the test side was brushed for 20 seconds. At the end of the 72-hour period, the stents were removed and prepared for microbiological analysis. Results: Both machined and plasma sprayed brushed surfaces presented statistically significant fewer bacteria than non-brushed surfaces. Similarly, regarding surface roughness, machined surfaces presented a total number of bacteria significantly smaller than those presented by plasma sprayed surfaces (P< 0.05). Statistically, the non-brushed machined turned surfaces presented a greater amount of Streptoccocus sp. when compared to the brushed machined surfaces. It was concluded that rough surfaces accumulated more dental plaque than polished surfaces. Both brushed surfaces presented less plaque accumulation, however, implant brushing was more effective on machined surfaces. (Am J Dent 2008;21:318-322).

Clinical versus laboratory adhesive performance to wet and dry demineralized primary dentin

Purpose: To evaluate the influence of dentin moisture on bond strengths of an etch-and-rinse bonding agent to primary dentin clinically and in the laboratory. Methods: The sample consisted of two groups of 20 caries-free primary second molars: molars in exfoliation period (clinical group) and extracted molars (laboratory group). Class I cavities were prepared in all specimens leaving a flat dentin surface on the pulpal floor. A two-step etch-and-rinse adhesive was vigorously rubbed on either dry (n= 5) or wet demineralized dentin (n= 5) under clinical or laboratory conditions. After restorative procedures, the teeth from the clinical group were extracted after 20 minutes. All samples were processed and underwent microtensile bond strength test and silver nitrate uptake evaluation under scanning electron microscopy. Results: Statistically higher bond strength values were observed when the bonding was performed under laboratory conditions and on a wet demineralized dentin. Most of the failures were adhesive and mixed irrespective of the experimental condition. Silver nitrate uptake occurred in all groups irrespective of the experimental condition. Resin-dentin bond strengths produced in the laboratory in primary teeth may overestimate those produced under clinical circumstances. (Am J Dent 2011;24:221-225).

Effect of prolonged application times on the durability of resin-dentin bonds

Objectives. To examine the effect of prolonged application time on the early and 3-year resin-dentin microtensile bond strength. Methods. Water/ethanol (Single Bond [SB]) and acetone-based systems (One Step [OS]) were employed. A flat superficial dentin surface was exposed in third human molars by wet abrasion. The adhesives were applied to a delimited area of 52 mm(2) on wet surfaces, for 40, 90, 150 and 300s. Four teeth were assigned for each experimental condition. Composite build-ups were constructed incrementally After water storage at 37 degrees C for 24 h, teeth were sectioned to obtain sticks with cross-sectional areas of 0.8 mm(2) to be tested in tension (0.5 mm/min) either immediately (IM) or after 3 years (3Y) of water storage. The microtensile bond strength (mu TBS) values were analyzed by two way repeated measures ANOVA and Tukey`s test (alpha = 0.05). Results. The 90- and 150-s groups achieved the highest IM mu TBS for OS (p < 0.01). For SB, the highest IM mu TBS values were observed after 300-s application (p < 0.01). Significant decreases in mu TBS were observed for OS in the 40- and 90-s groups after 3Y, except for the 150-s group. With regard to SB, after 3Y significant drops in mu TBS values were observed for the 40- and 150-s groups, except for the 300-s group. Significance. Prolonged application times can increase the immediate LTBS of two-step etch-and-rinse adhesive systems and make the adhesive layer more stable over time. (c) 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Do Low-shrink Composites Reduce Polymerization Shrinkage Effects?

Progress in polymer science has led to continuous reduction of polymerization shrinkage, exemplified by a new generation of ""low-shrink composites"". The common inference that shrinkage stress effects will be reduced in teeth restored with such restoratives with lower shrinkage was tested in extracted human premolars. Mesio-occluso-distal slot-shaped cavities were cut and restored with a conventional (SupremePlus) or low-shrink (RefleXions, Premise, Kalore, and LS) composite (N = 5). We digitized the coronal surfaces before and 10 min after restoration to determine cuspal deflection from the buccal and lingual volume change/area. We also determined the main properties involved (total shrinkage, post-gel shrinkage, degree of conversion, and elastic modulus), as well as microleakage, to verify adequate bonding. It was shown that, due to shrinkage stresses, buccal and lingual surfaces pulled inward after restoration (9-14 microns). Only Kalore and LS resulted in significantly lower tooth deformation (ANOVA/Student-Newman-Keuls post hoc, p = 0.05). The other two low-shrink composites, despite having the lowest and highest total shrinkage values, did not cause significant differences in cuspal deflection. Deflection seemed most related to the combination of post-gel shrinkage and elastic modulus. Therefore, even for significantly lower total shrinkage values, shrinkage stress is not necessarily reduced.

Scanning Electron Microscopy In Vitro Study on the Effect of Carisolv Application on Periodontally Diseased Root Surfaces

The purpose of this study was to evaluate the characteristics of diseased root surfaces treated by the association of scaling and the application of Carisolv. Twenty-four uniradicular periodontally involved teeth were used in this study The teeth were divided randomly into three groups: eight teeth were scaled and root planed until there was a complete visible removal of calculus (group 1), Carisolv was applied on the root surfaces of eight teeth twice for 30 seconds before scaling with a sharp curette (group 2), and eight teeth received the same treatment as in group 2 but with a blunt curette (group 3). Specimens were examined using scanning electron microscopy The superficial aspect of the roots from group 1 presented scratches that mirrored the curette cutting edge, and the smear layer completely covered the surface. Root surfaces from groups 2 and 3 also presented a smear layer that covered the surface completely but it was somewhat smoother than group 1. The use of Carisolv as an adjunct to scaling and root planing presented no advantage for smear layer removal over scaling alone, suggesting that no benefit is obtained by the use of Carisolv during periodontal mechanical treatment. (Int J Periodontics Restorative Dent 2011;31:91-95.)

Measuring Bond Strength Between Fiber Post and Root Dentin: A Comparison of Different Tests

Purpose The aim of this study was to evaluate the ability of bond strength tests to accurately measure the bond strength of fiber posts luted into root canals Materials and Methods The test methods studied were hourglass microtensile (HM), push-out (PS), modified push out (MP) and pull out (PL) The evaluated parameters were bond strength values, reliability (using Weibull analysis), failure mode (using confocal microscopy), and stress distribution (using finite element analysis) Forty human intact single rooted and endodontically treated teeth were divided into four groups Each group was assigned one of the test methods The samples in the HM and PS groups were 1 0 +/- 0 1 mm thick, the HM samples were hourglass shaped and the PS samples were disk shaped For the PL and MP groups, each 1 mm dentin slice was luted with a fiber post piece Three dimensional models of each group were made and stress was analyzed based on Von Mises criteria Results PL provided the highest values of bond strength followed by MP both of which also had greater amounts of adhesive failures PS showed the highest frequency of cohesive failures MP showed a more homogeneous stress distribution and a higher Weibull modulus Conclusion The specimen design directly influences the biomechanical behavior of bond strength tests

Comparison of dentin root canal permeability and morphology after irradiation with Nd:YAG, Er:YAG, and diode lasers

The aim of this study was to compare the effects of Nd:YAG, Er:YAG, and diode lasers on the morphology and permeability of root canal walls. The three laser wavelengths mentioned interact differently with dentin and therefore it is possible that the permeability changes caused will determine different indications during endodontic treatment. Twenty-eight human single-rooted teeth were instrumented up to ISO 40 and divided into four groups: group C, control (GC), non-laser irradiated; group N (GN), irradiated with Nd:YAG laser; group E (GE), with Er:YAG laser and group D (GD) with diode laser. After that, the roots were filled with a 2% methylene blue dye, divided into two halves and then photographed. The images were analyzed using Image J software and the percentage of dye penetration in the cervical, middle, and apical root thirds were calculated. Additional scanning electron microscopy (SEM) analyses were also performed. The analysis of variance (ANOVA) showed significant permeability differences between all groups in the middle and cervical thirds (p < 0.05). The Tukey test showed that in the cervical third, GN presented means of dye penetration statistically significantly lower than all of the other groups. In the middle third, GE and GD showed statistically higher dye penetration means than GC and GN. SEM analysis showed melted surfaces for GN, clean wall surfaces with open dentinal tubules for GE, and mostly obliterated dentinal tubules for GD. Er:YAG (2,094 nm) laser and diode laser (808 nm) root canal irradiation increase dentinal permeability and Nd:YAG (1,064 nm) laser decreases dentin permeability, within the studied parameters.