An in vitro investigation of peak insertion torque values of six commercially available mini-implants

This study compared peak insertion torque values of six commercially available self-drilling mini-implants [Mini Spider? screw (1.5 × 8 mm), Infinitas? (1.5 × 9 mm), Vector TAS? (1.4 × 8 mm), Dual Top? (1.6 × 8 mm), Tomas Pin? (1.6 × 8 mm), and Ortho-Easy? (1.7 × 6, 8, and 10 mm)]. Twenty implants each were drilled into acrylic rods at a speed of 8 rpm using a motorized torque measurement stand, and the values were recorded in Newton centimetres (Ncm). A further 20 Ortho-Easy? implants with a length of 6 and 10 mm were tested at 8 rpm; 20 implants of 6 mm length were also tested at 4 rpm. Kaplan-Meier estimates of the peak torque values were compared using the log-rank test with multiple comparisons evaluated by Sidak's test. There were significant differences in the maximum torque values for different mini-implants with the same length. The Mini Spider? screw and Infinitas? showed the lowest average torque values (6.5 and 12.4 Ncm) compared with Vector TAS?, Dual ToP?, Tomas Pin?, and Ortho-Easy? (30.9, 29.4, 25.4, and 24.8 Ncm, respectively). There was no correlation between the diameter of the implants and torque values. The Tomas Pin? showed the largest standard deviation (7.7 Ncm) and the Dual Top? implant the smallest (0.6 Ncm). Different insertion speeds did not result in significant differences in peak torque values but the 6 mm mini-implants showed significantly higher torque values than the 8 and 10 mm implants. Using a 'torque limiting' screwdriver or pre-drilling cortical bone to reduce insertion, torque appears justified for some of the tested implants.     

Leiomyomatous hamartoma of the midline maxillary gingival presenting as a congenital epulis: a case report with an immunohistochemical study

An otherwise-healthy 2-year-old Japanese female presented with a polyp-like lesion on the palatal surface at the incisive papilla. The appearance of the lesion was similar to that of a congenital epulis. The histological findings showed proliferating mesenchymal components that contained mainly smooth muscle admixed with collagen fibres, nerve fibres, small vessels and mucous salivary glands. The immunohistochemical staining findings for α-smooth-muscle actin, desmin and S-100 protein were all positive. The histological diagnosis was therefore leiomyomatous hamartoma, based on clinical microscopic observations.     

Relationship of metabolic syndrome to periodontal disease in Japanese women: the Hisayama Study

Recent studies have suggested that several systemic conditions--such as obesity, hypertension, hyperlipidemia, and diabetes--are related to periodontitis. The objective of this study was to examine the relationship between periodontitis and 5 components of metabolic syndrome--abdominal obesity, triglyceride level, high-density lipoprotein cholesterol level, blood pressure, and fasting blood sugar level--in 584 Japanese women. In multivariate analyses, persons exhibiting more components of metabolic syndrome had significantly higher odds ratios for a greater pocket depth and clinical attachment loss than did those with no components; the odds ratios for a greater pocket depth and clinical attachment loss of the persons exhibiting 4 or 5 components were 6.6 (95% confidence interval = 2.6-16.4) and 4.2 (95% confidence interval = 1.2-14.8), respectively. These results indicate that metabolic syndrome increases risk of periodontitis, and suggest that people exhibiting several components of metabolic syndrome should be encouraged to undergo a periodontal examination.     

The effect of aspirin on gingival crevicular fluid levels of inflammatory and anti-inflammatory mediators in patients with gingivitis

BACKGROUND: Inflammatory and anti-inflammatory mediators may play a significant role in patients with gingivitis. The purpose of this study was to assess the short-term effects of the systemic administration of two different concentrations of aspirin (81 and 325 mg/day, by mouth) on clinical periodontal parameters and gingival crevicular fluid (GCF) levels of 15-epi-lipoxin A4 (15-epi-LXA4), lipoxin A4, leukotriene B4 (LTB4), prostaglandin E2 (PGE2), and interleukin (IL)-6 and -1beta in a sample of naturally occurring gingivitis patients. METHODS: At day 0, after initial screening for entry, baseline periodontal parameters, including bleeding on probing (BOP), periodontal probing depths (PDs), and plaque index (PI) were measured, and GCF was sampled from 12 intrasulcular sites with filter paper strips for the measurement of six types of inflammatory and anti-inflammatory mediators using competitive enzyme immunoassay and enzyme-linked immunosorbent assay (prevalues). Forty-seven subjects were assigned randomly to one of three treatment groups: placebo (15 subjects); aspirin, 81 mg (16 subjects); and aspirin, 325 mg (16 subjects) once daily. On day 7, subjects were recalled for the measurement of periodontal parameters and collection of GCF samples for the measurement of six types of mediators (postvalues). RESULTS: Changes in inflammatory and anti-inflammatory mediator levels were not statistically significant for any of the three treatment groups. However, when pre- and postvalues were compared in the subjects receiving aspirin, 325 mg, there was a negative trend in the relationship between 15-epi-LXA4 and PGE2, whereas the relationship between LTB4 and PGE2 was not as strong. This might indicate that the subjects responding to aspirin-mediated PGE2 suppression effects produced higher 15-epi-LXA4 in GCF than non-responders. No statistically significant differences in PD and PI between pre- and postvalues were found for any of the three treatment groups. However, the results demonstrated a significant increase in BOP when aspirin, 325 mg was compared to placebo (P <0.001) and aspirin, 81 mg (P = 0.001). CONCLUSIONS: Aspirin can have an affect on BOP in naturally occurring gingivitis patients. Although most of the inflammatory mediators did not show significantly detectable changes after aspirin treatment for 7 days, the trend of aspirin-associated increases of 15-epi-LXA4 implied that this recently discovered aspirin-dependent eicosanoid may be associated with the increased incidence of BOP observed in the subjects who received aspirin therapy.     

Processing of ameloblastin by MMP-20

Ameloblastin (AMBN) cleavage products are the most abundant non-amelogenin proteins in the enamel matrix of developing teeth. AMBN N-terminal cleavage products accumulate in the sheath space between enamel rods, while AMBN C-terminal products localize within rods. We tested the hypothesis that MMP-20 is the protease that cleaves AMBN. Glycosylated recombinant porcine AMBN (rpAMBN) was expressed in human kidney 293F cells, and recombinant porcine enamelysin (rpMMP-20) was expressed in bacteria. The purified proteins were incubated together at an enzyme:substrate ratio of 1:100. N-terminal sequencing of AMBN digestion products determined that rpMMP-20 cleaved rpAMBN after Pro(2), Gln(130), Gln(139), Arg(170), and Ala(222). This shows that MMP-20 generates the 23-kDa AMBN starting at Tyr(223), as well as the 17-kDa (Val(1)-Arg(170)) and 15-kDa (Val(1)-Gln(130)) AMBN cleavage products that concentrate in the sheath space during the secretory stage. We conclude that MMP-20 processes ameloblastin in vitro and in vivo.     

A pilot study of quantitative assessment of mandible advancement using pressure-flow relationship during midazolam sedation

It has been proposed that a titration of the mandibular positioner would be a promising method for predicting the outcome of nasal continuous positive airway pressure (CPAP) therapy. This study was carried out to test the hypothesis that mandible advancement could be evaluated by analysis of inspiratory flow limitation using a titration procedure. To explore its effect, we examined upper airway pressure-flow relationships using a titrated mandible positioner during midazolam sedation. Non-flow limited inspiration occurred when the mandible was advanced 7.1 +/- 1.2 mm from centric occlusion position. In the centric occlusion position (0 mm advancement), Pcrit was -1.9 +/- 2.9 cmH2O and Rua was 23.3 +/- 4.5 cmH2O L(-1) s(-1). In the eMAP position, Pcrit was -7.3 +/- 1.9 cmH2O and Rua was 27.8 +/- 3.3 cmH2O L(-1) s(-1). Essentially no CPAP was required to overcome flow limitation in eMAP position, whereas 3.7 +/- 2.2 cmH2O CPAP was required in centric occlusion position. We conclude that assessing inspiratory flow limitation using a titrated mandible positioner was effective for estimating individual-matched mandible positions.     

Roles of CLCA and CFTR in electrolyte re-absorption from rat saliva

A molecular basis for Cl- re-absorption has not been well-characterized in salivary ductal cells. Previously, we found strong expression of a rat homologue proposed to be Ca2+-dependent Cl- channels (rCLCA) in the intralobular ducts of the rat submandibular gland. To address the question as to whether rCLCA and cystic fibrosis transmembrane conductance regulator (CFTR) are involved in Cl- re-absorption, we evaluated the electrolyte content of saliva from glands pre-treated with a small interfering RNA (siRNA). Retrograde injection into a given submandibular duct of an siRNA designed to knock down either rCLCA or CFTR reduced the expression of each of the proteins. rCLCA and CFTR siRNAs significantly increased Cl- concentration in the final saliva during pilocarpine stimulation. These results represent the first in vivo evidence for a physiological significance of rCLCA, along with CFTR, in transepithelial Cl- transport in the ductal system of the rat submandibular gland.