This study examined the effect of alumina air-abrasion with different pressure on bonding between an acrylic resin and casting alloys. Disk specimens (8 and 10 mm in diameter) were cast from a silver-palladium-copper-gold (Ag-Pd-Cu-Au, Castwell M.C.12) alloy and a titanium-aluminum-niobium alloy (Ti-6Al-7Nb, T-Alloy Tough). The disks were air-abraded with alumina particles (50-70 μm) under different air-pressures (0 unabraded, 0.1, and 0.6 MPa). The disk pairs were bonded together with a tri-n-butylborane (TBB)-initiated acrylic resin, and shear bond strengths were determined both before and after thermocycling. Bond strength varied from a maximum of 37.1 MPa to a minimum of 3.6 MPa for the Ag-Pd-Cu-Au alloy, whereas bond strength to Ti-6Al-7Nb alloy ranged from 34.7 MPa to 0.1 MPa. Specimens abraded with 0.6 MPa pressure recorded the greatest post-thermocycling bond strength (21.7 MPa and 17.9 MPa), and unabraded specimens showed the lowest strength (3.6 MPa and 0.1 MPa) for both alloys. Post-thermocycling bond strength to the Ag-Pd-Cu-Au alloy was higher than that to the Ti-6Al-7Nb alloy under identical air-abrading conditions. It can be concluded that alumina air-abrasion with an air-pressure of 0.6 MPa is effective in enhancing retentive characteristics of the TBB-initiated resin joined to the alloys. (J Oral Sci 51, 161-166, 2009)
To evaluate the cooperative effect of afferent signals from the pharynx and larynx on reflex swallowing, the interactive effect of afferent signals from the pharyngeal branch of the glossopharyngeal nerve (GPN-ph) and superior laryngeal nerve (SLN) was analyzed in detail in urethane-anesthetized rats. The electromyographic activity of the mylohyoid muscle was recorded as an indicator of swallowing activity. The onset latency of reflex swallowing was measured to evaluate the effects of electrical stimulation of these nerves, and found to become shorter following an increase in the GPN-ph and/or SLN stimulus frequency. During simultaneous electrical stimulation of the GPN-ph and SLN (frequency: 5-10 Hz, intensity: 30 μA, duration: 1.0 ms for each), the onset latency of reflex swallowing became shorter than that for stimulation of each nerve independently. The present findings suggest that spatiotemporal summation of afferent signals from the GPN-ph and SLN results in an increase of motoneuronal activity in the medullary swallowing center, thus enhancing reflex swallowing. (J Oral Sci 51, 167-171, 2009)
β-Adrenoceptor activation increases intracellular cAMP levels and consequently induces exocytotic amylase release in parotid acinar cells. Phosphodiesterase (PDE) catalyses the hydrolysis of cAMP, which terminates the downstream signaling of this second messenger. We investigated the involvement of PDE4, a cAMP-PDE, in β-adrenoceptor agonist-induced amylase release in mouse, rat and rabbit parotid acinar cells by using the specific PDE4 inhibitor rolipram. cAMP-PDE activity was detected in mouse, rat and rabbit parotid acinar cells. In the presence of rolipram, cAMP-PDE activity was reduced by about 31%, 38% and 33% in mouse, rat and rabbit parotid acinar cells, respectively. The increase in cAMP levels induced by the β-adrenoceptor agonist isoproterenol was enhanced in the presence of rolipram in mouse, rat and rabbit parotid acinar cells. Isoproterenol-induced amylase release, but not constitutive amylase release, was also enhanced in the presence of rolipram in mouse, rat and rabbit parotid acinar cells. These results suggest that the rolipram-sensitive cAMP-PDE, PDE4, is involved in β-adrenoceptor agonist-induced amylase release in parotid acinar cells. (J Oral Sci 51, 173-179, 2009)
Retreatment procedures in endodontic practice require complete removal of the original root filling materials. The aim of this study was to compare the amount of residual filling material on the walls of root canals that were obturated with gutta-percha or Resilon. Thirty extracted single-rooted human teeth were selected and instrumented by RaCe rotary instruments up to MAF #35. They were randomly divided into two groups of 15 teeth each. Group 1 was obturated with gutta-percha and AH26 sealer and group 2 was obturated with the Resilon/Epiphany system by lateral condensation technique. All canals were then retreated using Gates-Glidden drills, MAF #40 and chloroform. The teeth were split longitudinally and photographs were taken by a digital camera connected to a stereomicroscope and then samples were analyzed. The amount of residual material and time of retreatment were determined in each group at three levels in the canal. Data were analyzed by Mann-Whitney and Friedman tests. The Resilon group had significantly more residual material in the canal than the Gutta-percha group (P = 0.009). According to the level of the canal, the differences were statistically significant (P = 0.013) only in the Resilon group. Time required for retreatment in the two groups was not significantly different (P = 0.381). Orthograde retreatment of Resilon was less efficient than that of gutta-percha. (J Oral Sci 51, 181-185, 2009)
This study was carried out to compare the bacterial leakage of MTA used as a root-end filling material when it was kept in phosphate buffer saline (PBS) or normal saline. In this study, 72 freshly extracted teeth were used. The roots were randomly divided into four experimental groups of 15 each (groups I and II gutta-percha obturation + MTA, groups III and IV only MTA) and two positive and negative control groups of six each. The samples in groups I and III were kept in normal saline for 1 month while the samples in groups II and IV were kept in PBS. Enterococcus faecalis was used for determination of the bacterial penetration. Kaplan-Meier survival curve and χ2 test were employed for data analysis. The obturated samples with root-end filling showed significantly longer duration of resistance to bacterial penetration than canals without obturation (P < 0.05). The roots that were placed in PBS (groups II and IV) showed significantly less bacterial penetration in comparison with the roots that were stored in normal saline (P < 0.05). In conclusion, MTA, which acts as a bioactive material, should be placed in a synthetic tissue fluid before any leakage evaluation. (J Oral Sci 51, 187-191, 2009)
Oral lichen planus (OLP) is a chronic mucosal condition commonly encountered in dental practice. Lichen planus is believed to represent an abnormal immune response in which epithelial cells are recognized as foreign, secondary to changes in the antigenicity of the cell surface. It has various oral manifestations. The aim of the study was to evaluate the morphological characteristics of microcirculation of lingual lichen planus (LLP). Twenty patients (10 patients with LLP and 10 healthy patients) were examined by means of videocapillaroscopy. The left margin of the lingual mucosa was examined in each patient. The capillary loop length, loop diameter, and capillary density were analyzed on every capillaroscopic image. The results obtained using videocapillaroscopic software were subjected to statistical analysis. The density, loop length, and total diameter showed statistically significant differences. A remarkable increase in capillary density was shown. The microcirculation of LLP can be studied “in vivo” with the help of videocapillaroscopy, and it could be an indicator of the evolutionary condition of LLP, useful for the evaluation of the evolution or regression phases of the disease. (J Oral Sci 51, 193-197, 2009)
Different periodontitis definitions have been used in periodontal research. This study assessed the impact of case definition on the prevalence and extent rates of periodontitis. A data set including 340 periodontal records, collected in Belo Horizonte, Brazil, was used. Periodontitis was defined as: 1) one site with probing depth (PD) ≥ 4 mm; 2) clinical attachment level (CAL) ≥ 5 mm in ≥ 4 sites + one site with PD ≥ 4 mm; 3) CAL ≥ 6 mm in ≥ 2 teeth + one site with PD ≥ 5 mm; 4) ≥ 4 teeth with ≥ 1 sites with PD ≥ 4 mm + CAL ≥ 3 mm; 5a) interproximal CAL or PD ≥ 4 mm at ≥ 2 sites, not on the same tooth; and 5b) interproximal CAL of ≥ 6 mm at ≥ 2 sites, not on the same tooth + PD ≥ 5 mm at ≥ 1 proximal site. Definition 5 was determined to be the gold standard and the definitions were compared by means of agreement, sensitivity, specificity, and positive and negative predictive values. Prevalence and extent rates greatly varied, from 13.8% to 65.3% and from 9.7% to 55.6%, respectively. The use of different case definitions has a great impact on the prevalence and extent rates of periodontitis. (J Oral Sci 51, 199-206, 2009)
The aim of this study was to compare the apical leakage of roots obturated with gutta-percha using either an epoxy resin sealer (AH26) or a dual cure dentin binding agent (Excite DSC) as sealer in the presence or absence of smear layer with fluid filtration method. The canals of eighty-six, single-rooted premolars were instrumented until a #40 K-file fit at working length and then randomly divided into four groups (n = 20) with the remaining six used as controls. Groups 1 and 2 were filled with gutta-percha using AH26 as sealer; groups 3 and 4 were filled with gutta-percha and Excite DSC as sealer. Groups 1 and 3 were smear layer-positive, while group 2 and 4 were designated as smear layer-negative. After 3 days and 3 months, the samples were connected to a fluid filtration system. Analysis of data with the paired t-test showed that microleakage in AH26 groups (with and without smear layer) decreased significantly at 3 months compared to 3 days; however, in the DBA groups, the amount of microleakage at 3 days and 3 months was not significantly different. According to the results of this study, DBA (Excite DSC) had better apical sealing ability and could be applied clinically. (J Oral Sci 51, 207-213, 2009)
A study was conducted to evaluate the influence of laboratory light polymerization systems on the post-curing properties of a composite. An indirect composite (Sinfony) was polymerized with five polymerization systems (Visio system, Hyper LII, Pearlcure Light, Twinkle MIII, and UniXS II) using nine polymerization modes. After light exposure, Knoop hardness number, wear depth, and changes in gloss were determined. The highest hardness number was recorded with the use of the Hyper LII (120 s) and Pearlcure Light (120 s) units, whereas the lowest value was obtained with the Visio system and UniXS II (60 s). Six groups demonstrated comparable as well as higher wear resistance to toothbrush abrasion (Hyper LII 60 and 120 s, UniXS II 120 s, Pearlcure Light 60 and 120 s, and Twinkle MIII 120 s), and two groups exhibited lower wear resistance (Visio system and UniXS II 60 s). Gloss of the composite was not dependent on the polymerization mode used before wear testing. However, surface gloss was significantly reduced by toothbrush dentifrice abrasion. Within the limitations of the present experiment, it can be concluded that the Sinfony composite can be polymerized sufficiently with high-intensity light polymerization units. (J Oral Sci 51, 215-221, 2009)
The purpose of the present study was to evaluate the radiopacity of currently available dental luting materials. Five conventional cements, six resin-modified glass ionomers (RMGIs), two methyl methacrylate (MMA)-based acrylic resins (eight shades), and nine composite luting materials were evaluated. Radiographs of the specimens were taken together with tooth slices and aluminum step wedges. The density of the specimens was determined with a densitometer and was expressed in terms of the equivalent thickness of aluminum per 2.0-mm unit thickness of specimen. The radiopacity values for human enamel and dentin were 4.3 and 2.3 mm Al/2.0 mm specimen, respectively. The values for materials ranged from 5.1 to 12.9 for conventional luting materials, from 3.4 to 6.3 for RMGIs, from less than 0.5 to 7.3 for MMA resins, and from 2.3 to 9.9 for the composite luting materials. A zinc phosphate cement showed the highest value (12.9), whereas five shades of MMA resin resulted in the lowest value (less than 0.5). Two RMGIs and three composite luting materials exhibited radiopacity values between those of enamel (4.3) and dentin (2.3). It can be concluded that the radiopacity value of luting materials varies considerably, and that care must be taken when selecting luting materials, considering the material composition of restorations. (J Oral Sci 51, 223-230, 2009)
The anterior loop is defined as where the mental neurovascular bundle crosses anterior to the mental foramen then doubles back to exit the mental foramen. It cannot be seen clinically but can be detected in 11-60% of panoramic radiographs. As this anatomical structure is important in determining the placement position of endosseous implants in the mandibular premolar region, a pilot study was undertaken to determine its visibility on dental panoramic radiographs in dentate subjects of various age groups. One or more anterior loops were visible in 39 (40.2%) radiographs encompassing 66 sites (34.4%). Interestingly, anterior loops were most commonly observed bilaterally, followed by on the right side of the mandible only. An anterior loop on the left side only was observed in just 1 radiograph. Visibility of anterior loops reduced as the age of subjects increased. More than half (58.1%) of subjects aged 20-29 years exhibited at least one anterior loop; this gradually reduced to only 15 percent of subjects aged 50 and older. There was no association between visualization of the anterior loop and subject gender. (J Oral Sci 51, 231-237, 2009)
A total of 455 children (242 males and 213 females) aged 5-6 years were investigated for their pain reactions to maxillary and mandibular infiltration anesthesia, middle superior alveolar nerve block, posterior superior alveolar nerve block, greater palatine nerve block, nasopalatine nerve block, and inferior alveolar nerve block, and the responses were quantified using the sound, eye and motor (SEM) scale. Administration of nasopalatine nerve block produced maximum pain (median SEM score: 10) while that of posterior superior alveolar nerve block and inferior alveolar nerve block was accompanied by minimum pain (3 and 4, respectively). There was no significant gender-specific difference in pain reactions (P = 0.39). Administration of local anesthesia in the maxilla was more painful than injections into the mandible (7 versus 5, P < 0.05). Furthermore, infiltration into the anterior and posterior segments of the maxilla produced maximum and minimum pain reactions, respectively (8 versus 3, P < 0.001). It seems that the anatomical location of an injection is one of the most important determinants of pediatric pain reaction, and that mandibular injections are generally less painful. Prioritization of treatment by consideration of site-dependent variability in pain sensitivity may help to achieve optimal behavioral control during dental treatment in young children. (J Oral Sci 51, 239-243, 2009)
This study evaluated the rate of polymerization (Rp) and degree of conversion (DC) of Panavia F when self- or dual-activated, and the influence of either using or not using a primer containing co-initiators (ED Primer) mixed with the material. The conversion reaction was monitored using real-time infrared spectroscopy with an attenuated total reflectance device. The cement was mixed, put onto the device and irradiated for 20 s (dual-cured). A self-cured group was also prepared. Similarly, dual- and self-cured groups were evaluated after mixing ED Primer with the cement. The DC was monitored for 1 h and the Rp was calculated. For the dual-cured mode, the most significant effect of ED Primer was to reduce the Rpmax. For the self-cured mode, the primer was shown to be essential for polymerization of Panavia F: without ED Primer, the reaction started only after approximately 500 s, with a final DC of 50%, whereas a continuous increase in conversion was observed for the group mixed with ED Primer, with a final DC of 74%. The ED primer is essential for proper polymerization of Panavia F; the cement becomes independent of the light when the primer is used. (J Oral Sci 51, 255-259, 2009)
There are conflicting data regarding the role of interleukin (IL)-17 in periodontal health and disease. However, IL-18 levels are known to increase with the severity of periodontal disease. The present study was performed to explore the role of these proinflammatory cytokines in periodontal disease progression, and also to clarify the effect of periodontal treatment on their concentration. Sixty age- and gender-matched subjects were divided into three groups each consisting of 20 subjects on the basis of gingival index (GI), probing pocket depth (PPD), clinical attachment loss (CAL) and radiological parameters (bone loss): healthy (group 1), gingivitis (group 2) and chronic periodontitis (group 3), while group 3 patients after treatment constituted group 4. GCF samples collected from all the groups were assayed by enzyme-linked immunosorbent assay to estimate the levels of IL-17 and IL-18. IL-18 levels in GCF increased proportionally with the severity of periodontal disease, and decreased after treatment. However, IL-17 levels in GCF were nearly zero. Since our data indicate an absence of IL-17 in GCF, it cannot be considered as a biomarker of periodontal disease progression, at least in Indian populations. However, IL-18 appears to be a good inflammatory biomarker. (J Oral Sci 51, 261-266, 2009)
The purpose of the current study was to evaluate the color stability of two indirect composite materials (Sinfony and Pearleste) polymerized with different laboratory polymerization systems. Disk specimens were prepared with their proprietary polymerization systems (Visio and Pearlcure systems) or with a metal halide light polymerization unit (Hyper LII) for 60, 120, and 180 s. After storage at 37°C for 24 h, the specimens were immersed in either purified water or tea. Color change between baseline evaluation and after 4 weeks was determined with a dental chroma meter (ShadeEye NCC) using black and white backgrounds. CIE 1976 L*a*b* values were determined, and they were converted into ΔE*ab values. The ΔE*ab value of the Sinfony material immersed in tea was the highest when the material was polymerized with the proprietary Visio system. The Pearleste material immersed in purified water and tea was not affected substantially by the polymerization systems. Among the 12 groups polymerized with the Hyper LII units, ΔE*ab values of 11 groups were significantly lower for the Pearleste material than for the Sinfony material. It can be concluded that the Pearleste material was stable against color change when the material was polymerized with either the Pearlcure system or with the Hyper LII unit. (J Oral Sci 51, 267-273, 2009)
A survey was carried out to compare periodontal health status and oral health behavior between Japanese and Chinese dental students. Subjects consisted of 118 students at Nihon University School of Dentistry and 92 students at the school of Stomatology, Nanjing Medical University. Saliva occult blood test was performed to classify whether subjects may have periodontal disease. Further questionnaires were given to evaluate different lifestyles and oral hygiene habit. The positive rate of the saliva occult blood test in Japanese dental students was 13.6%, and that of Chinese dental students was 43.5%. Bleeding from gingiva as a subjective symptom was as follows: Japansese 7.6%, Chinese 37.0%. Japanese dental students brushed for 13.5 min each day. The rate for Chinese students was 4.6 min. Use of interdental devices was as follows: Japanese 33.1%, Chinese 7.6%. Differences of periodontal disease rates between Japanese and Chinese dental students are thought to be differences in oral hygiene, indicating the need for improvements in hygiene measures in Nanjing City. The establishment and strengthening of oral hygiene education, including the importance of tooth brushing for prevention of periodontal disease, has been proposed. (J Oral Sci 51, 275-281, 2009)
Podoplanin, a transmembrane glycoprotein, has been considered to be expressed specifically by lymphatic endothelial cells. However, recent studies have shown that the protein is expressed in a variety of normal as well as neoplastic tissues, and that its expression might be related to cell migration and invasion. In this study, we examined podoplanin expression in inflamed gingival tissues using an immunohistochemical method. Positive immunoreactivity for podoplanin was found in the cell membrane and cytoplasm of basal cells of oral gingival epithelium when severe inflammatory cell infiltration was present in the connective tissue just under the epithelium. When inflammatory changes were weak or absent, little or no reactivity for podoplanin in the basal cells was observed. Positive reactivity for podoplanin was also detected in basal cell extensions. Surprisingly, strong immunoreactivity for podoplanin was observed in all layers of oral sulcular and junctional epithelia associated with severe inflammatory reaction in the connective tissue. These findings suggest that increased expression of podoplanin in gingival epithelium is related to the progression of chronic periodontitis. (J Oral Sci 51, 283-287, 2009)
Betel quid containing areca nut and chewing tobacco is used in many parts of India. In this study we evaluated the micronuclei (MN) in buccal mucosa of healthy individuals from southern India, who were regularly chewing a mixture of betel leaf, areca nut and tobacco. A total of 44 subjects were examined. The study population included 15 chewers, 14 chewers with smoking habit and 15 controls with the mean age of 38.57 ± 0.54, 34.50 ± 0.95, and 33.28 ± 0.89 years, respectively. The mean percentage of MN was 1.90 ± 1.03 in chewers, 2.00 ±1.12 in chewers with smoking habits and 0.81 ± 0.66 in controls. There was no significant difference between the mean percentages of the two experimental groups. It can be concluded that a mixture of betel leaf, areca nut, and tobacco is unsafe for oral health. (J Oral Sci 51, 289-292, 2009)
Ameloblastic fibroma (AF) is an extremely rare true mixed benign tumor that can occur in either the mandible or the maxilla, but is most frequently found in the posterior region of the mandible. It usually occurs in the first two decades of life and is associated with tooth enclosure, causing a delay in eruption or altering the dental eruption sequence. AF is diagnosed on routine radiographic evaluation and is clinically and radiographically similar to ameloblastic fibrodontoma and odontoma, which makes an accurate diagnosis mandatory. There is controversy in the literature as to whether treatment should be conservative or agressive. A conservative treatment strategy, such as enucleation and curettage, is usually sufficient. However, extensive lesions require radical treatment. We describe a case of ameloblastic fibroma with a very unusual clinical manifestation: it demonstrated considerable extension but no associated impacted tooth, was located in the anterior region of the mandible, and became symptomatic in the fifth decade of life. A radical surgical approach was taken, with immediate reconstruction. (J Oral Sci 51, 293-296, 2009)
This article reports an uncommon case of talon cusp on a geminated permanent maxillary central incisor, including details of the clinical and radiographic findings and treatment. A 28-year-old woman presented at the university dental clinic, and intraoral examination revealed a maxillary central incisor of abnormal size with a prominent accessory cusp on the lingual aspect. The case was diagnosed as talon cusp on a geminated tooth. Early diagnosis of this anomaly is important since it may cause clinical problems such as esthetic concerns, caries and tooth crowding. In the present case, these anomalies did not complicate the subsequent endodontic treatment. (J Oral Sci 51, 297-300, 2009)
Cranio-dento-facial findings in a case of Noonan syndrome in a 13-year, 3-month-old male are reported. Oral examination of the patient revealed a narrow, high arched palate, malocclusion and congenitally missing teeth. Even though cephalometric measurements showed an increased vertical facial pattern (GoGn/SN = 38.46°), a severe deep bite (9 mm) was evident. Noonan syndrome is characterized by ocular, facial, cardiac, and dental anomalies, although it is often unrecognized by clinicians. Although differential diagnosis of this syndrome is difficult, the cranio-dento-facial structures show specific findings that can be diagnosed by a dental specialist. The present report describes a new case of this syndrome from a dental viewpoint. (J Oral Sci 51, 301-306, 2009)
Myofibroma is a rare benign nodular tumor of the soft tissues, bones, or internal organs, and may affect both children and adults. It is mostly found in the head and neck region, although uncommon in the jaw bones, where only a few lesions have been described. Radiographically, it may appear as a well-defined unilocular radiolucent entity simulating a cystic or odontogenic lesion. Histopathologic findings alone may be insufficient for a final diagnosis, and immunostaining for markers such as vimentin, alpha-smooth muscle actin, desmin and S-100 may be required. Intraosseous myofibroma is a diagnostic challenge and requires careful histopathologic, immunohistochemical and radiographic correlation. The present article describes a conservatively treated intraosseous myofibroma that occurred in a 7-year-old girl. The clinical, radiographic, histopathologic and immunohistochemical features are discussed. (J Oral Sci 51, 307-311, 2009)
Chondrolipomas are benign mesenchymal tumors characterized by the proliferation of mature adipocytes associated with variable amounts of mature cartilaginous tissue. We describe here a case of chondrolipoma of the tongue in a 30-year-old man. The patient reported the presence of the lesion for approximately 10 years. Intraoral clinical examination revealed a nodular, sessile, pink mass of firm consistency, which was located along the midline of the posterior region on the dorsal surface of the tongue. An excisional biopsy was performed and histopathological examination revealed a well-delimited proliferation of mature adipocytes arranged in lobules and separated by fibrous connective tissue septa. Islands of mature cartilaginous tissue were identified in close proximity to the fibrous connective tissue septa, as well as lacunae filled with chondrocytes. No myxoid areas, lipoblasts, atypias, hyperchromasia or mitosis were detected. After 5 years of follow-up, the patient shows no signs of recurrence. Chondrolipomas are uncommon in the oral cavity, with only nine cases being reported in the international literature (Pubmed Database). (J Oral Sci 51, 313-316, 2009)
The increasing interest in esthetics and the subsequent need to solve related problems such as dentin hypersensitivity and root caries have favored the development of many surgical techniques that permit the coverage of exposed roots. In this case, a 47-year-old female patient presented seeking resolution of dentin hypersensitivity with multiple gingival recessions in the upper anterior region. A coronally positioned flap combined with connective tissue grafting using a single-incision technique was applied to achieve root coverage. The treated site showed improvement of root coverage with reduction of dentin hypersensitivity without any probing defect or significant complication. The single-incision technique may be an option for harvesting of graft material in the treatment of multiple gingival recessions. (J Oral Sci 51, 317-321, 2009)
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