Incidental findings in cone beam computed tomography volumes: Calcified head-and-neck atheromas detected during dental evaluation.

PURPOSE: Atheromas can be detected incidentally in routine dental cone beam computed tomography (CBCT) images. This study aims to assess prevalence and risk factors associated with these vascular lesions. MATERIALS AND METHODS: The maxillofacial CBCTs of 458 subjects were evaluated and divided into 4 groups based on the presence of calcified atheroma: subjects with no calcified atheroma, subjects with intracranial calcified atheroma (ICA), subjects with extracranial calcified atheroma (ECA), and subjects exhibiting combined lesions. Age, sex, medical conditions, family history, and size were documented. Analysis of variance followed by a multiple comparison test was used for data satisfying parametric test assumptions. Chi-squared tests were used to assess categorical data. The Spearman Rho test was used to assess the correlation between the incidence of calcified atheroma and subjects' medical condition. RESULTS: Of the 458 CBCTs evaluated, 29.90% presented with calcified atheroma. Calcified atheroma prevalence was significantly higher in older patients versus younger patients (p = 0.004) and in males compared to females (p = 0.004). Males were more likely to have the combination of ICA and ECA, whereas females were more likely to have ICA alone (p ≤ 0.040). Patients with calcified atheroma were significantly more likely to have a history of hyperlipidemia (p = 0.001), hypertension (p = 0.001), and myocardial infarction/coronary artery diseases (p = 0.001). Overall, patients exhibiting both intracranial and extracranial lesions were more likely to have cardiovascular risk factors (p = 0.001). CONCLUSION: Incidentally detected calcified atheromas in CBCTs are common. Subjects with combined atheroma lesions are at higher risk for cardiovascular disease. The diagnosis of incidental calcified atheromas in CBCT's warrants early referral to medical specialists, especially if there is no medical history of existing cardiovascular disease.

Accuracy and Efficiency of a Dynamic Navigation System for Locating Calcified Canals.

INTRODUCTION: Calcified canals present a challenge during endodontic treatments. The purpose of this study was to compare the accuracy and efficiency of a dynamic navigation system (DNS) to the freehand (FH) method for locating calcified canals in human teeth. METHODS: Sixty human single-rooted teeth with canal obliteration were selected and mounted in dry cadaver jaws. Based on cone-beam computed tomographic scans of the jaws, the drilling path and depth were virtually planned to use X-Guide software (X-Nav Technologies, LLC, Lansdale, PA). Access preparation was made with navigation in the DNS group and without guidance in the FH group by 2 operators with different levels of experience. Postoperative cone-beam computed tomographic scans were taken of all teeth. Linear and angular deviations and reduced dentin thickness at 2 levels were measured. The time for locating the canal, the number of mishaps, and the unsuccessful attempts were determined and analyzed. RESULTS: The mean linear and angular deviations, reduced dentin thickness (at both levels), the time for access cavity preparation, and the number of mishaps in the DNS group were significantly less than the FH group (P ≤ .05). The unsuccessful attempts were not different between the 2 groups (P > .05). The time for access preparation was significantly shorter for the board-certified endodontist in the FH group (P ≤ .05). CONCLUSIONS: The DNS was more accurate and more efficient than the FH technique in locating calcified canals in human teeth. This novel DNS can help clinicians avoid catastrophic mishaps during access preparation in calcified teeth.

Opioid-prescribing Habits of Practitioner and Educator Members of the American Association of Endodontists: Report of a National Survey.

Dentists and physicians alike often prescribe opioids for dental pain management. The purpose of this study was to identify the common practices among United States endodontists for prescribing opioids to their patients. A descriptive, cross-sectional survey was developed to query 1000 American Association of Endodontists members from all 7 districts in the United States. The 20-question survey addressed provider demographics, types and frequency of medications prescribed, and clinical scenarios that compelled prescription-writing habits. The anonymous survey was electronically mailed. There was a preference to prescribe nonsteroidal anti-inflammatory drugs and/or acetaminophen followed by hydrocodone to manage endodontic pain. The majority of respondents limited an opioid prescription to ≤4 days. Different demographics played a role in the response to direct questions if they ever felt or succumbed to pressure toward prescribing opioids. Opioids are the second most prescribed medication to manage endodontic postoperative pain. Practice background was a significant factor in feeling pressure to prescribe an opioid.

Accuracy of Dynamic Virtual Articulation: Trueness and Precision.

PURPOSE: To study the effects of altering condylar settings and pin openings on the trueness and precision of virtual articulators vs. mechanical articulators. MATERIALS AND METHODS: Maxillary and mandibular typodonts with fiducial markers were mounted on a mechanical Artex-CR articulator, and the mandibular teeth were prepared to allow guidance solely by the posterior determinants of the articulator and the incisal table. The relationship of the mounted typodonts was preserved digitally by scanning using manufacturer transfer plate adaptors. On the mechanical articulator, pattern resin was allowed to set between the maxillary and mandibular occlusal surfaces (area #25-30) at the endpoints of dynamic movements at 3 condylar inclinations (SCI): 10°, 30°, and 45°, n = 12/inclination, or at 3 incisal pin openings (2, 5, and 10 mm, n = 12/opening). All other articulator settings were kept constant. Resin specimens attached to the typodonts were scanned within 5 minutes of setting, then removed, and the articulated typodonts rescanned. Fixed dental prostheses (FDPs) #25-30 were designed on the virtual articulator using identical parameters to the mechanical articulator. Dynamic virtual movements were used to sculpt the design, and a file of the design was saved. The files of both types of samples were aligned and overlaid. Interocclusal separation was measured in triplicate at the indentation created by the mesiolabioincisal point angle on the incisal edge of #8 and the mesiobucco-occlusal point angle of #3. Trueness and precision of both types of articulators were calculated and compared using one-way ANOVA, followed by the Tukey HSD test (α = 0.05). RESULTS: There was no statistically significant difference at altered pin openings in either trueness (F = 0.202, p = 0.37) or precision (F = 3.134, p = 0.09) for the majority of measurements. The only significant difference was in the precision between the 2 types of articulators at 5 mm incisal opening, and only at the anterior measurement point (F = 15.134, p = 0.0008); however, these differences were less than 100 µm. When the SCI was altered, there was no statistically significant difference (F = 3.624, p > 0.05) between the virtual and mechanical articulators in trueness for 5 of the 6 measurements obtained (F = 3.624, p = 0.07) or for all of the precision measurements (F = 3.529, p = 0.07). The one trueness measurement that was significantly different (F = 9.237, p = 0.006) occured at SCI of 10°, and it was less than 100 µm. CONCLUSIONS: Dynamic movements on the virtual articulator were shown to be as true and precise as to the mechanical articulator. When there were deviations, these deviations were less than 100 µm and thus, these deviations may not be clinically relevant.

A Modified Resin Sealer: Physical and Antibacterial Properties.

INTRODUCTION: The purpose of this study was to investigate the physical and antibacterial properties of a resin sealer mixed with a quaternary ammonium compound, dimethylaminododecyl methacrylate (DMAHDM) and nanosilver (NAg). METHODS: A pilot study was completed to determine the highest concentrations of DMAHDM and NAg that did not significantly alter the physical properties (setting time, flow, solubility, and dimensional change) of AH Plus (Dentsply Sirona, York, PA) when added to the sealer. These concentrations were selected to create a modified resin sealer (mAH Plus). A modified direct contact test evaluated antibacterial properties of AH Plus, DMAHDM + AH Plus, NAg + AH Plus, and mAH Plus at days 1, 7, and 14 against Enterococcus faecalis. RESULTS: Concentrations of 2.5% DMAHDM and 0.15% NAg were added to AH Plus. The flow of mAH Plus was significantly decreased but still within American National Standards Institute/American Dental Association specifications. There were no significant differences in setting time, solubility, or dimensional change. On day 1, 0.15% NAg + AH Plus, 2.5% DMAHDM + AH Plus, and mAH Plus were significantly more effective against E. faecalis compared with AH Plus (P < .05). On days 7 through 14, 2.5% DMAHDM + AH Plus and mAH Plus continued to be significantly more antibacterial than AH Plus (P < .05). CONCLUSIONS: The addition of 0.15% NAg and 2.5% DMAHDM did not adversely affect the physical properties of AH Plus, and mAH Plus was significantly more antibacterial against E. faecalis.

Healing of Apical Periodontitis after Nonsurgical Root Canal Treatment: The Role of Statin Intake.

INTRODUCTION: Numerous previously undocumented factors may influence the healing of apical periodontitis (AP). The aim of this cohort study was to analyze the association between statin medication intake during the follow-up period and healing of AP. METHODS: Patients who self-reported being on statins during nonsurgical root canal treatment or retreatment and patients who reported never taking statins were included. All patients who received treatment on a tooth with periapical radiolucency in the postgraduate endodontics clinic at the University of Maryland School of Dentistry (2011-2014) were invited for follow-up 2 to 5 years after treatment. Healing was determined using the periapical index (PAI). Two calibrated endodontists assessed outcomes blinded to the statin intake. The association of statin intake and healing of endodontic treatment (ie, healed [PAI 1-2]/not healed [PAI 3-5]) was analyzed using the Fisher exact test. Logistic regression analysis was used to explore the association between statin intake and treatment outcome, controlling for the following confounding variables: diabetes mellitus, cardiovascular disease, and smoking, with confidence intervals set at 95%. RESULTS: A total of 60 cases were included in the final analysis, including 30 patients taking statins and 30 patients not taking statins as the control. The Fisher exact test showed significantly higher healing at the 2-year or greater follow-up in patients taking statins compared with controls (93.0% vs 70%; Fisher exact test, P = .02). CONCLUSIONS: The results of this study show a significant association between long-term statin intake and healing of AP after nonsurgical root canal treatment.

Antibacterial Efficacy and Discoloration Potential of Endodontic Topical Antibiotics.

INTRODUCTION: The optimal concentration for the use of endodontic topical antibiotics is not known. The aims of this study were to determine the minimum bactericidal concentrations (MBCs) and minimum inhibitory concentrations (MICs) of metronidazole, ciprofloxacin, minocycline, Augmentin (GlaxoSmithKline, Research Triangle Park, NC), and tigecycline against common endodontic pathogens and to evaluate ex vivo the antibacterial efficacy and discoloration effect of triple antibiotic paste (TAP), Augmentin, and tigecycline at different concentrations using a slow-release hydrogel scaffold. METHODS: Using the Epsilometer test method (Etest; bioMérieux USA, St Louis, MO), MICs and MBCs of selected antibiotics were determined against Fusobacterium nucleatum, Porphyromonas gingivalis, Streptococcus intermedius, and Enterococcus faecalis. Biofilms of these bacterial species were then grown in extracted single-rooted teeth anaerobically for 3 weeks. Root canals were filled with TAP, Augmentin, and tigecycline at concentrations of 1 or 0.1 mg/mL in a degradable hydrogel scaffold or pure TAP at 1 g/mL for 7 days. Coronal discoloration was evaluated spectrophotometrically at 1, 2, and 3 weeks after dressing. RESULTS: MIC/MBC data showed significant efficacy of tigecycline, Augmentin, and minocycline compared with the other antibiotics (P < .05). Significant differences were found when comparing the log10 colony-forming units of all experimental groups (P < .05). TAP at 1 g/mL had no bacterial growth but caused the greatest discoloration. Hydrogel mixtures with TAP, Augmentin, or tigecycline at 1 mg/mL significantly reduced bacterial growth and the number of positive samples compared with those at 0.1 mg/mL (P < .05) with minimal discoloration. CONCLUSIONS: TAP, Augmentin, and tigecycline in a hydrogel at 1 mg/mL reduced bacterial growth significantly with minimal color change.

Evaluating ceramic crown margins with digital radiography.

STATEMENT OF PROBLEM: Radiographs aid in clinically determining crown fit, specifically interproximal margins where tactile and visual methods may be limited. However, investigations of the utility of digital radiographs as a tool for evaluating the marginal openings of ceramic crowns are lacking. PURPOSE: The purpose of this in vitro study was to assess whether marginal adaptation for ceramic crowns and for metal-ceramic crowns with a metal collar can be identified with digital radiographs. MATERIAL AND METHODS: One lithium disilicate crown, 1 fluorapatite crown, and 1 metal-ceramic crown were fabricated for a maxillary premolar. The crowns were attached to a custom-designed device that allowed the marginal discrepancy to be changed. A total of 10 increments were measured starting at 0 to 20 µm and increasing every 20 µm to a maximum opening of 180 to 200 µm. At each increment, 2 radiographs were made of the crowns, using a digital sensor, 1 perpendicular to and 1 at 80 degrees to the long axis of the tooth. To test whether digital radiographs could be used to accurately identify "acceptable" and "unacceptable" margins, 21 dentists were asked to rate the radiographs as "acceptable" or "unacceptable." The chi square test was used to analyze differences between the dentists' evaluations and the actual marginal opening (α=.05). For the purposes of this study, a marginal discrepancy greater than 80 µm was considered "unacceptable." RESULTS: Of all marginal discrepancies exceeding 80 µm, 78.6% of the metal-ceramic crown radiographs were incorrectly scored as "acceptable" (P<.001). These radiographs were identified as false positives. Lithium disilicate (66.1%) and fluorapatite (45.8%) crowns were more likely to be incorrectly evaluated as "unacceptable" (P<.001) and identified as false negatives. CONCLUSIONS: Using digital radiographs to evaluate marginal adaptation without clinical examination is not by itself an accurate method of evaluating the marginal fit of complete coverage crowns. The marginal fit of the tested metal-ceramic crowns tended to be evaluated incorrectly as acceptable. The marginal fit of the tested ceramic crowns tended to be evaluated incorrectly as unacceptable.

Free gingival grafts for implants exhibiting lack of keratinized mucosa: a prospective controlled randomized clinical study.

INTRODUCTION: To evaluate clinical and radiographic outcomes following free gingival grafts (FGGs) around implants with limited keratinized mucosa (KM) during 18 months follow-up compared to oral prophylaxis without augmentation. MATERIALS AND METHODS: This prospective controlled randomized blind clinical study investigated 41 implants displaying lack of KM in 28 subjects. After baseline examination, 14 subjects in the experimental group received FGGs followed by oral prophylaxis and 14 subjects in the control group received oral prophylaxis only. The width of KM, the level of mucosal margin, pocket depths, plaque index, and gingival index (GI) were assessed at baseline, 6, 12, and 18 months. Changes in crestal bone levels, from baseline, were assessed at 18 months. RESULTS: There was a significant gain in KM in the FGG group compared to controls at 6, 12, 18 months. The mean GI was significantly lower for the FGG group at all follow-ups. Crestal bone loss in the FGG group was significantly less than the control group (mesial: p = 0.0005, distal: p = 0.042) at 18 months. CONCLUSIONS: Free gingival graft for implants exhibiting lack of KM is a viable treatment option to reduce mucosal inflammation and to maintain crestal bone level in the short term.

Effect of locator abutment height on the retentive values of pink locator attachments: An in vitro study.

STATEMENT OF PROBLEM: Currently, no guidelines exist to help in the selection of Locator abutments for implants at different heights. PURPOSE: The purpose of this in vitro study was to evaluate the effect of the differential heights of pairs of Locator abutments on the retention of overdentures after 6 months of simulated function. MATERIAL AND METHODS: In vitro testing was performed with 4 sets of average-sized edentulous mandible analogs with 2 implants placed in the canine positions. There were 10 specimens in each of the 4 groups, with a total sample size of 40. Four groups of 2 implant-retained overdentures were fabricated, with Locator attachments at different vertical levels with differences of 0, 2, 4, and 6 mm. The overdentures were subjected to simulated function for a period corresponding to 6 months of clinical service and then tested with a universal testing machine for changes in peak load-to-dislodgement. The data were analyzed using 1-way ANOVA followed by the Tukey honest significant differences test (α=.05). RESULTS: Varying the heights of Locator abutments had a statistically significant effect on the retentive values of the pink Locator attachments after 6 months of simulated function (F=7.342, P=.001). The peak load-to-dislodgement ranged from 32.3 N (95% confidence interval [CI]: 26.0 to 38.6) for group 0 mm to 53.6 N (95% CI: 46.3 to 60.8) for group 6 mm. When the difference in Locator abutment heights was 2 and 4 mm, the peak load was 37.1 N (95% CI: 32.3 to 42.0) and 41.9 N (95% CI: 31.2 to 52.7). Statistical analysis revealed that the retention of group 0 mm and group 2 mm was significantly lower than group 6 mm. The retention of group 4 mm was not significantly different from groups 0 mm, 2 mm, or 6 mm. CONCLUSIONS: Although significant differences were found among the groups, these differences were small and may not be clinically detectable.

Isolation, Characterization, and Differentiation of Dental Pulp Stem Cells in Ferrets.

INTRODUCTION: The ferret canine tooth has been introduced as a suitable model for studying dental pulp regeneration. The aim of this study was to isolate and characterize ferret dental pulp stem cells (fDPSCs) and their differentiation potential. METHODS: Dental pulp stem cells were isolated from freshly extracted ferret canine teeth. The cells were examined for the expression of stem cell markers STRO-1, CD90, CD105, and CD146. The osteo/odontogenic and adipogenic differentiation potential of fDPSCs was evaluated. Osteogenic and odontogenic marker genes were evaluated using quantitative real-time polymerase chain reaction (qRT-PCR) on days 1, 4, and 8 after osteo/odontogenic induction of fDPSCs including dentin sialophosphoprotein (DSPP), dentin matrix protein-1, osteopontin, and alkaline phosphatase. Human dental pulp cells were used as the control. The results were analyzed using 3-way analysis of variance. RESULTS: fDPSCs were positive for STRO1, CD90, and CD105 and negative for CD146 markers with immunohistochemistry. fDPSCs showed strong osteogenic and weak adipogenic potential. The overall expression of DSPP was not significantly different between fDPSCs and human dental pulp cells. The expression of DSPP in osteo/odontogenic media was significantly higher in fDPSCs on day 4 (P < .01). The overall expression of dentin matrix protein-1, osteopontin, and alkaline phosphatase was significantly higher in fDPSCs (P = .0005). CONCLUSIONS: fDPSCs were positive for several markers of dental pulp stem cells resembling human DPSCs and appeared to show a stronger potential to differentiate to osteoblastic rather than odontoblastic lineage.

Adherence of Streptococcus mutans on lithium disilicate porcelain specimens.

STATEMENT OF PROBLEM: Streptococcus mutans can adhere at restored tooth margins to cause recurrent caries. Limited information about surface quality and bacterial adherence is available for lithium disilicate ceramic materials. PURPOSE: The purpose of this in vitro study was to investigate how bacterial adherence is influenced by commercially available preparations of lithium disilicate ceramic materials. MATERIAL AND METHODS: Seventeen rectangular specimens (10×10×4 mm) were fabricated for each type of lithium disilicate material: pressed (Press), milled (CAD), fluorapatite layered (ZirPress/Ceram), and glazed (Ceram Glaze). The surface roughness of each specimen was assessed before incubation with wild-type S mutans for 48 hours at 37°C with Brain Heart Infusion broth media under anaerobic conditions. Adherent bacteria were sonicated, diluted, and plated in triplicate for quantification using the plate count method to assay for colony forming units (CFUs) as an indication of bacterial viability. Statistical analysis was performed with SPSS using an analysis of variance (ANOVA) followed by the Tukey Honestly Significant Difference (HSD) test (α=.05). The Pearson r was used to evaluate the correlation between surface roughness and adherence. RESULTS: The surface roughness of Ceram Glaze (1.32 ±0.19 µm) was significantly the highest, followed by ZirPress/Ceram (0.71 ±0.09 µm), which was significantly rougher than the Press (0.11 ±0.02 µm) and CAD (0.10 ±0.02 µm) groups, which were not significantly different from each other. (F=513.898, P<.001). CFUs (cells/mL) of S mutans were also significantly the highest for Ceram Glaze (61.82 ±13.76), followed by ZirPress/Ceram (28.53 ±2.40), which had significantly higher adherence than CAD (12.86 ±1.70) and Press (6.62 ±2.74), which were not significantly different from each other. (F= 201.721, P<.001). A strong positive association was found between bacterial count and surface roughness (r=.95, P<.001). CONCLUSIONS: The surface roughness of differently prepared lithium disilicate ceramic restorations is closely related to the adherence of S mutans.

Cephalometry in adults and children with neurofibromatosis type 1: Implications for the pathogenesis of sphenoid wing dysplasia and the "NF1 facies".

BACKGROUND: Neurofibromatosis type 1 (NF1) is a common, autosomal dominant tumor-predisposition disorder that arises secondary to mutations in the tumor suppressor gene NF1. Cephalometry is an inexpensive, readily available and non-invasive technique that is under-utilized in studying the NF1 craniofacial phenotype. An analysis of NF1 cephalometry was first published by Heervä et al. in 2011. We expand here on that first investigation with a larger cohort of adult and pediatric patients affected with NF1 and sought objective insight into the NF1 facies, said to feature hypertelorism and a broad nasal base, from cephalometric analysis. METHODS: We obtained cephalograms from 101 patients with NF1 (78 adults and 23 children) from two NF1 protocols at the National Institutes of Health. Each subject had an age-, gender- and ethnicity-matched control. We used Dolphin software to make the cephalometric measurements. We assessed the normality of differences between paired samples using the Shapiro-Wilk test and evaluated the significance of mean differences using paired t-tests and adjusted for multiple testing. We explored the relationship between the cephalometric measurements and height, head circumference and interpupillary distance. RESULTS: In this dataset of American whites with NF1, we confirmed in a modestly larger sample many of the findings found by Heerva et al. in an NF1 Finnish cohort. We found a shorter maxilla, mandible, cranial base, (especially anteriorly, p = 0.0001) and diminished facial height in adults, but not children, with NF1. Only one adult exhibited hypertelorism. CONCLUSIONS: The cephalometric differences in adults arise in part from cranial base shortening and thus result in a shorter face, mid-face hypoplasia, reduced facial projection, smaller jaw, and increased braincase globularity. In addition, we suggest that NF1 sphenoid bone shortening, a common event, is consistent with an intrinsic NF1 bone cell defect, which renders the bone more vulnerable to a random "second hit" in NF1, leading to sphenoid wing dysplasia, a rare event.

Caries management by risk assessment (CAMBRA) and its effect on the surface roughness of various restorative materials.

STATEMENT OF PROBLEM: Whether topical anticaries medicaments used in the oral environment will affect the surface integrity of restorative materials is uncertain. PURPOSE: The purpose of this in vitro study was to investigate the effect of various anticaries agents on the surface roughness of 3 different restorative materials. MATERIAL AND METHODS: Sixty-four specimens of each restorative material (feldspathic porcelain, Ni-Cr metal ceramic alloy, and Ti-6Al-4V titanium alloy) were prepared and separated into 4 equal groups for soaking in anticaries agents (Prevident Dental Rinse, ACT mouth wash, chlorhexidine gluconate, and water). A profilometer was used to measure surface roughness before and after soaking the materials for 2 years of simulated usage. The mean change in surface roughness for each specimen was calculated. Statistical analysis was performed with a 2-way ANOVA, followed by the Tukey HSD test (α=.05). RESULTS: A significant interaction was found between the materials and anticaries agents (F=2.64, P=.02). The significant interaction was between Prevident and chlorhexidine gluconate. Porcelain specimens soaked in Prevident produced a negative change (-0.072 ±0.35 µm) in surface roughness (smoother surface), while chlorhexidine gluconate produced a positive change (0.094 ±0.42 µm) in surface roughness (rougher surface). CONCLUSION: Within the limitations of this in vitro study, it can be concluded that Prevident Dental Rinse and chlorhexidine gluconate may cause a change in the surface roughness of feldspathic porcelain.

Development of novel dental adhesive with double benefits of protein-repellent and antibacterial capabilities.

OBJECTIVES: Secondary caries at the tooth-restoration margins remains a main reason for restoration failure. The objectives of this study were to: (1) combine protein-repellent 2-methacryloyloxyethyl phosphorylcholine (MPC) with quaternary ammonium dimethylaminohexadecyl methacrylate (DMAHDM) to develop a new dental adhesive with double benefits of protein-repellent and antibacterial capabilities for the first time; and (2) investigate the effects on protein adsorption, anti-biofilm activity, and dentin bond strength. METHODS: MPC and DMAHDM were incorporated into Scotchbond Multi-Purpose (SBMP) primer and adhesive. Dentin shear bond strengths were measured using extracted human molars. Protein adsorption onto the adhesive resin surfaces was determined by the micro bicinchoninic acid (BCA) method. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate biofilm metabolic activity, colony-forming unit (CFU) counts, lactic acid production and live/dead staining of biofilms on resins. RESULTS: Incorporation of 7.5% MPC and 5% DMAHDM into primer and adhesive did not adversely affect the dentin shear bond strength (p>0.1). The resin with 7.5% MPC+5% DMAHDM had protein adsorption that was nearly 20-fold less than SBMP control (p<0.05). The resin with 7.5% MPC+5% DMAHDM had much stronger antibacterial effects than using MPC or DMAHDM alone (p<0.05). Biofilm CFU counts on the resin with 7.5% MPC+5% DMAHDM were reduced by more than 4 orders of magnitude, compared to SBMP control. SIGNIFICANCE: The use of double agents (protein-repellent MPC+antibacterial DMAHDM) in dental adhesive achieved much stronger inhibition of biofilms than using each agent alone. The novel protein-repellent and antibacterial bonding agent is promising to reduce biofilm/plaque buildup and reduce recurrent caries at the tooth-restoration margins.

Effect of implant angulation and impression technique on impressions of NobelActive implants.

STATEMENT OF PROBLEM: How the configuration of the NobelActive internal conical connection affects implant impressions is uncertain. PURPOSE: The purpose of this study was to measure the effect in vitro of closed and open tray impression techniques for NobelActive implants placed at various angulations. MATERIAL AND METHODS: Six NobelActive implants were placed in a master maxillary cast as follows: 0 degrees of angulation to a line drawn perpendicular to the occlusal plane in the first molar area, 15 degrees of angulation to a line drawn perpendicular to the occlusal plane in the first premolar area, and 30 degrees of angulation to a line drawn perpendicular to the occlusal plane in the lateral incisor area. Twelve open tray and 12 closed tray impressions were made. Occlusal, lateral, and frontal view photographs of the resulting casts were used to measure the linear and angular displacement of implant analogs. Statistical analysis was performed with a factorial analysis of variance (ANOVA), followed by the Tukey HSD test (α=.05). RESULTS: No significant difference was found in the impressions made of NobelActive implants with the open or closed tray technique (linear displacement: F=0.93, P=.34; angular displacement: F=2.09, P=.15). In addition, implant angulation (0, 15, or 30 degrees) had no effect on the linear or angular displacement of impressions (linear displacement: F=2.72, P=.07; angular displacement: F=0.86, P=.43). Finally, no significant interaction was found between impression technique and implant angulation on NobelActive implants (F=0.25, P=.77; F=1.60, P=.20). CONCLUSIONS: Within the limitations of this study, impression technique (open vs closed tray) and implant angulation (0, 15, and 30 degrees) had no significant effect on in vitro impressions of NobelActive implants.

Synergistic degradation of dentin by cyclic stress and buffer agitation.

Secondary caries and non-carious lesions develop in regions of stress concentrations and oral fluid movement. The objective of this study was to evaluate the influence of cyclic stress and fluid movement on material loss and subsurface degradation of dentin within an acidic environment. Rectangular specimens of radicular dentin were prepared from caries-free unrestored 3rd molars. Two groups were subjected to cyclic cantilever loading within a lactic acid solution (pH = 5) to achieve compressive stresses on the inner (pulpal) or outer sides of the specimens. Two additional groups were evaluated in the same solution, one subjected to movement only (no stress) and the second held stagnant (control: no stress or movement). Exterior material loss profiles and subsurface degradation were quantified on the two sides of the specimens. Results showed that under cyclic stress material loss was significantly greater (p ≤ 0.0005) on the pulpal side than on the outer side and significantly greater (p ≤ 0.05) under compression than tension. However, movement only caused significantly greater material loss (p ≤ 0.0005) than cyclic stress. Subsurface degradation was greatest at the location of highest stress, but was not influenced by stress state or movement.

The Effect of Cleft Size in Infants With Unilateral Cleft Lip and Palate on Mixed Dentition Dental Arch Relationship.

OBJECTIVE: To determine the relationship between infant cleft size and dental arch relationship in the mixed dentition in patients with complete unilateral cleft lip and palate. DESIGN: Retrospective analysis of mixed longitudinal records. PATIENTS: A total of 29 consecutively enrolled patients with unilateral cleft lip and palate participated in a longitudinal study that included dental casts prior to lip surgery (T1: age 1 month), prior to palate surgery (T2: age 10 months), and in mixed dentition (T3: age 9 years). INTERVENTIONS: All infants were managed with lip repair (2.5 months), hard palate repair (12 months), and soft palate repair (16 months) but without any presurgical orthopedic treatment and no orthodontic intervention prior to mixed dentition records. MAIN OUTCOME MEASURES: The outcome measures included determination of an infant cleft severity ratio, defined as the ratio of palatal cleft area to palatal surface area, at both T1 and T2, and the 9-year-old (T3) dental arch relationship as determined using the GOSLON Yardstick. The correlation between the infant cleft severity ratio at T1 and T2 and the later GOSLON Yardstick score at T3 was determined using Pearson r. The intrarater reliability of the infant cleft severity ratio was assessed with Pearson r and the interrater reliability of the GOSLON Yardstick ratings, by weighted kappa. RESULTS: Reliability for the infant cleft severity ratio method was r = .92 to .95, and for GOSLON ratings κ = .81 to .91. There was no significant correlation between 1-month infant cleft severity ratio and GOSLON (r = .3) and 10-month infant cleft severity ratio and GOSLON (r = .1). CONCLUSIONS: Cleft size versus the amount of palatal tissue available for repair and concern over more scarring with a greater infant cleft severity ratio were not factors in affecting the eventual dental arch relationship.

Importance of age on the dynamic mechanical behavior of intertubular and peritubular dentin.

An experimental evaluation of human coronal dentin was performed using nanoscopic dynamic mechanical analysis (nanoDMA). The primary objectives were to quantify any unique changes in mechanical behavior of intertubular and peritubular dentin with age, and to evaluate the microstructure and mechanical behavior of the mineral deposited within the lumens. Specimens of coronal dentin were evaluated by nanoDMA using single indents and in scanning mode via scanning probe microscopy. Results showed that there were no significant differences in the storage modulus or complex modulus between the two age groups (18-25 versus 54-83 yrs) for either the intertubular or peritubular tissue. However, there were significant differences in the dampening behavior between the young and old dentin, as represented in the loss modulus and tanδ responses. For both the intertubular and peritubular components, the capacity for dampening was significantly lower in the old group. Scanning based nanoDMA showed that the tubules of old dentin exhibit a gradient in elastic behavior, with decrease in elastic modulus from the cuff to the center of tubules filled with newly deposited mineral.

The effect of various disinfectants on dental shade guides.

STATEMENT OF PROBLEM: Dental shade guides are used to evaluate tooth color before prosthodontic procedures and are subjected to disinfection after use. The effect of disinfection on shade guides has not been thoroughly investigated. PURPOSE: The purpose of this study was to evaluate the effect of disinfectants on the color of shade tabs. MATERIAL AND METHODS: Changes in the color (ΔE) of VITA Classical Shade Guide tabs were measured with a VITA Easyshade spectrophotometer in the CIELAB system and calculated after being subjected to Cavicide, Asepticare TB, Sporicidin, and distilled water (control) over a simulated period of 2 years. Statistical analysis was accomplished by a 2-way analysis of variance followed by the Tukey honestly significant difference (HSD) test (α=.05). RESULTS: A significant difference was noted in the degree of shade tab color change, depending on the type of disinfectant used (F=153.2, P<.001). No significant difference was noted in the amount of shade tab color change that occurred after disinfection among the different shade tabs used (F=0.611, P=.865), nor was a significant interaction noted between the type of disinfectant and the different shade tabs used (F=0.7, P=.919). Asepticare TB showed the least significant amount of change (ΔE=0.401), and Sporicidin (ΔE=0.889) and the control (ΔE=0.969) showed significantly more color change than Asepticare TB but less than Cavicide (ΔE=1.198). CONCLUSIONS: The average total CIELAB color difference for 50% human perceptibility is approximately 1 unit (under standardized laboratory conditions). In the oral cavity, however, an average change of 3.7 ΔE units could still allow teeth to be perceived as having the same color. Therefore, although the results are statistically significant, they may not be clinically important.