Faculty Bibliography

Background/purpose: The ability to save a digital copy of a fabricated denture is poignant for large dental institutions. The purpose of this study was to evaluate the trueness and precision of an intraoral scanner (IOS) in its ability to digitally duplicate a complete denture (CD) and evaluate the possible effects of file resolution reduction on different exported media types. Materials and methods: A desktop scanner was used to scan a complete mandibular denture and utilized as the control file. An IOS was used to scan the same denture and exported into both standard triangular language (STL) and polygon (PLY) file types and stored for additional analysis. The different file types at original resolution were compared to the desktop scan (DS100) to evaluate the accuracy of the IOS. Then the STL (Groups S100, S75, S50, S25) and PLY (Groups P100, P75, P50, P25) files were reduced in their resolutions to evaluate any statistical discrepancies in the volumetric analysis of the scan using the Hausdorff distance (HD) and dice similarity coefficient (DSC). Results: When compared to the desktop scan (14888.40 mm³), the measured volume of the exported STL (Group S100: 15236.45 ± 114.67 mm³) and PLY (Group P100: 15231.71 ± 97.12 mm³) files from the IOS produced a similarity of 98.34% and 98.39% respectively. The similarity of the IOS files at different resolutions ranged from 99.99% to 99.96%. Conclusion: We conclude that the IOS used in this study demonstrates very high trueness and precision when digitally duplicating complete dentures.

BACKGROUND:Successful osseointegration of endosteal dental implants has been attributed to implant design, including the macro-, micro- and nano- geometric properties. Based on current literature pertaining to implant design, the resultant cellular and bone healing response is unknown when the thread thickness of the implants is increased, resulting in an increased contact area in implants designed with healing chambers. The aim of this study was to evaluate the effect of two implant designs with different thread profiles on the osseointegration parameters and implant stability at 3- and 6-weeks in vivo using a well-established preclinical dog model. MATERIAL AND METHODS/METHODS:A total of 48 type V Ti alloy implants were divided in two groups according to their thread design (D1= +0.1x/mm and D2= +0.15x/mm) and placed in an interpolated fashion into the radii of six beagles. Insertion torque was measured at time of placement, radii were extracted for histological processing following 3- and 6-week healing intervals. Histologic and histomorphometric analyses were performed in terms of bone to implant contact (%BIC) and bone area fraction occupancy within implant threads (%BAFO). Statistical analyses were performed through a linear mixed model with fixed factors of time and implant thread design. RESULTS:Surface roughness analysis demonstrated no significant differences in Sa and Sq between D1 and D2 implant designs, which confirmed that both implant designs were homogenous except for their respective thread profiles. For insertion torque, statistically significant lower values were recorded for D1 in comparison to D2 (59.6 ± 11.1 and 78.9 ± 10.1 N⋅cm, respectively). Furthermore, there were no significant differences with respect to histological analysis and histomorphometric parameters, between D1 and D2 at both time points. CONCLUSIONS:Both thread profiles presented equivalent potential to successfully osseointegrate in the osteotomies, with D2 yielding higher mechanical retention upon placement without detrimental bone resorption.

Although generally regarded as degradatory enzymes, certain proteases are also signaling molecules that specifically control cellular functions by cleaving protease-activated receptors (PARs). The four known PARs are members of the large family of G protein-coupled receptors. These transmembrane receptors control most physiological and pathological processes and are the target of a large proportion of therapeutic drugs. Signaling proteases include enzymes from the circulation, from immune, inflammatory epithelial and cancer cells, as well as from commensal and pathogenic bacteria. Advances in our understanding of the structure and function of PARs provide insights into how diverse proteases activate these receptors to regulate physiological and pathological processes in most tissues and organ systems. The realization that proteases and PARs are key mediators of disease, coupled with advances in understanding the atomic level structure of PARs and their mechanisms of signaling in subcellular microdomains, has spurred the development of antagonists, some of which have advanced to the clinic. Herein we review the discovery, structure and function of this receptor system, highlight the contribution of PARs to homeostatic control, and discuss the potential of PAR antagonists for the treatment of major diseases.

Head and neck squamous cell carcinoma (HNSCC) causes more severe pain and psychological stress than other types of cancer. Despite clinical evidence linking pain, stress, and cancer progression, the underlying relationship between pain and sympathetic neurotransmission in oral cancer is unknown. We found that human HNSCC tumors and mouse tumor tissue are innervated by peripheral sympathetic and sensory nerves. Moreover, [beta]-adrenergic 1 and 2 receptors ([beta]-AR) are overexpressed in human oral cancer cell lines, and norepinephrine treatment increased [beta]-AR2 protein expression as well as cancer cell proliferation in vitro. We have recently demonstrated that inhibition of tumor necrosis factor alpha (TNF[alpha]) signaling reduces oral cancer-induced nociceptive behavior. Norepinephrine-treated cancer cell lines secrete more TNF[alpha] which, when applied to tongue-innervating trigeminal neurons, evoked a larger Ca2+ transient; TNF-TNFR inhibitor blocked the increase in the evoked Ca2+ transient. Using an orthotopic xenograft oral cancer model, we found that mice demonstrated significantly less orofacial cancer-induced nociceptive behavior during systemic [beta]-adrenergic inhibitory treatment with propranolol. Furthermore, chemical sympathectomy via guanethidine led to a significant reduction in tumor size and nociceptive behavior. We infer from these results that sympathetic signaling modulates oral cancer pain via TNF[alpha] secretion and tumorigenesis. Further investigation of the role of neuro-cancer communication in cancer progression and pain is warranted.

BACKGROUND/PURPOSE/OBJECTIVE:This paper describes the changes in maxillary arch morphology in infants with bilateral cleft lip and palate (BCLP) following nasoalveolar molding (NAM) and with follow up to assess the need for secondary alveolar bone grafting (ABG) and premaxillary repositioning surgery at preadolescence. METHODS/DESCRIPTION/UNASSIGNED:Treatment records of infants with BCLP treated with NAM between 2003 and 2013 were reviewed. Patients with complete BCLP who underwent NAM and had complete sets of maxillary casts at T 0 pre-NAM (mean = 27 days), T 1 post-NAM (mean = 6 months and 5 days), and T 2 before palate surgery (mean = 11 months and 15 days) were included. The sample comprised 23 infants (18 male, 5 female). Casts were digitized and analyzed using three dimensional software. The need for secondary ABG and premaxillary repositioning surgery was assessed at preadolescent follow-up (mean = 8.3 years). RESULTS:Cleft width was reduced on average by 4.73 mm (SD ± 3.15 mm) and 6.56 mm (SD ± 4.65) on the right and left sides, respectively. At T 1, 13 (56.52%) patients underwent bilateral gingivoperiosteoplasty (GPP), 8 (34.78%) patients unilateral GPP, and 2 patients (8.7%) did not undergo GPP. 34/46 clefts sites (73.91%) underwent GPP while 12 (26.08%) did not. At preadolescent follow-up of 19 patients, 7 patients (36.84%) did not need ABG on either side, 8 (42.10%) needed ABG on 1 side, and 4 (21.05%) needed ABG on both sides. None of the patients needed premaxillary repositioning surgery. CONCLUSIONS:Nasoalveolar molding treatment significantly improves the position of the premaxilla before primary repair, and there is a significant reduction in the need for secondary ABG and premaxillary repositioning surgery at preadolescence.