Inflammatory mediators in fluid extracted from the coronal occlusal dentine of trimmed teeth.

BACKGROUND: Chemokines and cytokines may occur in dentinal fluids in response to local infection and inflammation. To test this hypothesis, we assessed the presence and concentration of inflammatory mediators in fluid extracted from the coronal occlusal dentine of trimmed teeth. DESIGN: Freshly extracted sound, carious, and restored molars were trimmed through the enamel to expose the underlying dentine, etched with 35% phosphoric acid, and rinsed. Fluid was extracted from the coronal occlusal dentine of these trimmed teeth by centrifugation at 2750 × g for 30 min. RESULTS: When assessed by MALDI-TOF, fluid extracted from the coronal occlusal dentine from 16 molars contained at least 117 peaks with different masses suggesting that this fluid was rich with molecules within the appropriate mass range of potential mediators. Indeed, when assessed for chemokines and cytokines, fluid extracted from the coronal occlusal dentine from 25 extracted molars with caries lesions, 10 extracted restored molars with occlusal amalgam, and 77 extracted sound molars contained IL-1ß, TNF-α, IL-6, IL-8, IL-12(p70), and IL-10. A significant elevation was found for TNF-α (p=0.041) in extracted fluid from teeth restored with amalgam fillings. CONCLUSIONS: Overall, fluid extracted from the coronal occlusal dentine of trimmed teeth may be useful in identifying proteins and other molecules in dentine and pulpal fluids and determining their role as mediators in the pathogenesis of oral infection and inflammation.

Effect of screw diameter on orthodontic skeletal anchorage.

INTRODUCTION: Many case reports have documented the successful use of titanium miniscrews for orthodontic anchorage. However, the literature lacks a well-controlled study examining the effect of miniscrew diameter on anchorage force resistance. The purpose of this in-vitro study was to compare the force resistance of larger-diameter monocortical miniscrews to smaller-diameter monocortical miniscrews; and to compare the force resistance of larger-diameter monocortical miniscrews to smaller-diameter bicortical miniscrews. METHODS: Ninety-six titanium alloy screws were placed into 24 hemisected maxillary and 24 hemisected mandibular specimens between the first and second premolars. Specimens were randomly and evenly divided into 2 groups. In the first group, 24 large-diameter screws (2.5 x 17 mm) and with 24 small-diameter screws (1.5 x 15 mm) were placed monocortically. In the second group, 24 large-diameter screws (2.5 x 17 mm) were placed monocortically and 24 small-diameter screws (1.5 x 15 mm) were placed bicortically. All screws were subjected to tangential force loading perpendicular to the miniscrew with lateral displacement of 0.6 mm. Statistical analyses, including the paired-samples t test and the 2-samples t test, were used to quantify screw force-deflection characteristics. One-way analysis of variance (ANOVA) with the post-hoc Tukey studentized range test was used to determine any significant differences, and the order of those differences, in force anchorage values among the 3 screw types at maxillary and mandibular sites. RESULTS: Mean mandibular and maxillary anchorage force values of the 2.5-mm monocortical screws were significantly greater than those of the 1.5-mm monocortical screws (P <0.01). No statistically significant differences in mean mandibular anchorage force values were found between the 2.5-mm monocortical screws and the 1.5-mm bicortical screws. However, mean maxillary anchorage force values of the 1.5-mm bicortical screws were significantly greater than those of the 2.5-mm monocortical screws (P <0.01). Data analyzed with 1-way ANOVA with the post-hoc Tukey studentized range tests indicated that the mean mandibular and maxillary force values of the 2.5-mm monocortical screws and the 1.5-mm bicortical screws were significantly greater than those of the 1.5-mm monocortical screws (P <0.01). Based on the 2-samples t test, mean anchorage force values at mandibular sites were significantly greater than at maxillary sites for the 2.5-mm monocortical screws and the 1.5-mm monocortical screws. There were no statistically significant differences in mean anchorage force values between maxillary and mandibular sites for the 1.5-mm bicortical screws. CONCLUSIONS: In vitro, larger-diameter (2.5 mm) monocortical screws provide greater anchorage force resistance than do smaller-diameter (1.5 mm) monocortical screws in both the mandible and the maxilla. Smaller-diameter (1.5 mm) bicortical screws provide anchorage force resistance at least equal to larger-diameter (2.5 mm) monocortical screws. An alternative to placing a larger-diameter miniscrew for additional anchorage is a narrower bicortical screw.

Bicortical vs monocortical orthodontic skeletal anchorage.

INTRODUCTION: Case reports have documented the use of titanium miniscrews in providing skeletal anchorage for orthodontic tooth movement. Success rates as low as 50% have been reported for screw retention in either the facial or the lingual cortical plates (monocortical placement). The purpose of this in-vitro study was to test the hypothesis that bicortical miniscrew placement (across the entire width of the alveolus) gives the orthodontist superior force resistance and stability (anchorage) compared with monocortical placement. METHODS: Forty-four titanium alloy screws, 1.5 x 15.0 mm, were placed in 22 hemi-sected maxillae and mandibular specimens between the first and second premolars. Half were placed monocortically, half were placed bicortically, and all were subjected to tangential force loading perpendicular to the miniscrew through a lateral displacement of 1.5 mm. Bone samples were sectioned and bone thickness at the screw sites measured. Statistical analyses, consisting of paired samples t tests, 2-samples t tests, Spearman rank correlation tests, and Fisher exact tests, were used to compare monocortical with bicortical screw force-deflection characteristics and stability. Additionally, 2-dimensional plane-stress finite-element models of bicortical and monocortical screw placement subjected to similar loading were analyzed. RESULTS: As hypothesized, deflection force values were significantly greater for bicortical screws than for monocortical screws placed in both the maxilla and the mandible (P <0.01 in each instance). Furthermore, force values at mandibular sites were significantly greater than those at maxillary sites for both types of screws. No significant differences in deflection force values were found between the right and left sides of the jaws, or between coronal and apical alveolar-process screw positions. A significant increasing relationship was found between mandibular buccal bone thickness and deflection force for monocortical screws only, and no relationship was found between maxillary bone thickness and deflection force for monocortical or bicortical screws. Monocortical screws were significantly more mobile after force application than bicortical screws. Finite-element analysis indicated lower cortical bone stresses with bicortical placement than with monocortical placement, and these results were consistent with in-vitro experimental findings. CONCLUSIONS: Bicortical miniscrews provide the orthodontist superior anchorage resistance, reduced cortical bone stress, and superior stability compared with monocortical screws.

Comparing diet, oral hygiene and caries status of adult methamphetamine users and nonusers: a pilot study.

BACKGROUND: Methamphetamine users are reported to have marginal dietary habits and high caries rates. The authors compared retrospective dietary patterns, oral hygiene behaviors and current oral health status of methamphetamine users and nonusers in a pilot study. METHODS: Eighteen adults with a history of methamphetamine use (methamphetamine users) and 18 age- and sex-matched control subjects (nonusers) completed retrospective questionnaires concerning meal patterns, food group intakes, beverage habits, oral hygiene behaviors, smoking behaviors and drug use. The authors performed oral examinations to identify the number of remaining teeth, the number of teeth with obvious decay and presence of visible plaque. RESULTS: Methamphetamine users were more likely to snack without eating defined meals (P = .026), consume regular soda pop (that is, carbonated beverage with sugar) (P = .018), never brush their teeth (P < .001) and smoke (P < .001) than were nonusers. Users had more visible plaque (P < .001), fewer molars (P = .001) and more decay on anterior teeth (P < .001), premolars (P < .001) and molars (P < .001) than did nonusers. CONCLUSIONS: The results of this pilot study are consistent with anecdotal reports; methamphetamine users have more gross caries than do nonusers. Marginal dietary and oral hygiene behaviors associated with methamphetamine use likely increase caries risk. CLINICAL IMPLICATIONS: Patients at risk or suspected of using methamphetamine require detailed oral hygiene instruction and extensive dietary counseling.

Molecular profiling of giant cell tumor of bone and the osteoclastic localization of ligand for receptor activator of nuclear factor kappaB.

Giant cell tumor of bone (GCT) is a generally benign, osteolytic neoplasm comprising stromal cells and osteoclast-like giant cells. The osteoclastic cells, which cause bony destruction, are thought to be recruited from normal monocytic pre-osteoclasts by stromal cell expression of the ligand for receptor activator of nuclear factor kappaB (RANKL). This model forms the foundation for clinical trials in GCTs of novel cancer therapeutics targeting RANKL. Using expression profiling, we identified both osteoblast and osteoclast signatures within GCTs, including key regulators of osteoclast differentiation and function such as RANKL, a C-type lectin, osteoprotegerin, and the wnt inhibitor SFRP4. After ex vivo generation of stromal- and osteoclast-enriched cultures, we unexpectedly found that RANKL mRNA and protein were more highly expressed in osteoclasts than in stromal cells, as determined by expression profiling, flow cytometry, immunohistochemistry, and reverse transcriptase-polymerase chain reaction. The expression patterns of molecules implicated in signaling between stromal cells and monocytic osteoclast precursors were analyzed in both primary and fractionated GCTs. Finally, using array-based comparative genomic hybridization, neither GCTs nor the derived stromal cells demonstrated significant genomic gains or losses. These data raise questions regarding the role of RANKL in GCTs that may be relevant to the development of molecularly targeted therapeutics for this disease.

A retrospective review of treatment of the odontogenic keratocyst.

PURPOSE: The purpose of this study was to evaluate different surgical treatment methods for odontogenic keratocysts and the outcome of those treatments over a 25-year period. PATIENTS AND METHODS: A retrospective review was performed of 40 patient charts treated at the University of Iowa Hospitals and Clinics (Iowa City, IA) from 1977 to 2002 with the diagnosis of odontogenic keratocyst. Demographic data were collected along with lesion location, symptoms present at initial presentation, surgical treatment rendered, length of follow-up, and incidence of recurrence. RESULTS: Surgical treatments included enucleation, enucleation with Carnoy's solution, peripheral ostectomy, peripheral ostectomy with Carnoy's solution, and en bloc resection. Recurrence was found in 9 to 40 patients. Seven of 9 recurrences (78%) occurred in 5 years or less, with 2 (22%) occurring more than 5 years after initial treatment. Patients treated with enucleation had a recurrence rate of 54.5% (6 of 11 patients). One of 2 patients treated with enucleation and Carnoy's solution had a recurrence. Those treated with peripheral ostectomy had a recurrence rate of 18.2% (2 of 11). Peripheral ostectomy with Carnoy's solution had no recurrences (0/13). CONCLUSION: Treatment of an odontogenic keratocyst with peripheral ostectomy, with or without the use of Carnoy's solution, had a significantly lower rate of recurrence. Treatment with enucleation, with or without the use of Carnoy's solution was associated with a significantly higher recurrence rate.