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 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.

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.

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.

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.

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.

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.

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.

The effect of number and distribution of unsplinted maxillary implants on the load transfer in implant-retained maxillary overdentures: an in vitro study.

STATEMENT OF PROBLEM: There is little information as to how the number and distribution of implants affect the amount of load transmitted to the palate in implant-retained maxillary overdentures. PURPOSE: The purpose of this study was to evaluate the effect of the number and distribution of dental implants on the load transmitted to the palate. MATERIAL AND METHODS: Eight implant analogues were placed in a replica of an average sized edentulous maxilla corresponding to the position of canines, first and second premolars, and first molars. The anteroposterior distance between the centers of implants in each quadrant was 8 mm. Fifteen denture bases were fabricated to fit the edentulous maxilla analogue. The denture bases were attached to the oral analogue using 6 different configurations of attachments (6 groups): Either no Locator attachments were used (control group), or the 2 most anterior attachments were attached, or 4 implants were engaged with a distance of 8, 16, or 24 mm between the centers of implants on left and right side, and finally, when all 8 attachments were activated. A force-measuring sensor was used to measure the force transmitted to the palate when a static force of 245 N was applied on the occlusal rims of the denture bases. Data (Newtons) were analyzed using 1-way ANOVA and Tukey's HSD test α=.05). RESULTS: The mean (SD) amount of force measured on the palate when the overdentures were supported by 4 Locator attachments; [49.84 (26.52) at 8 mm spacing], [24.42 (15.05) at 16 mm spacing], [35.66 (22.94) at 24 mm spacing] was significantly lower than when no attachments [90.98 (20.20), control], or when 2 Locator attachments were used [76.07 (27.63)] (P<.001). When the overdentures were supported by 8 Locator attachments, the force measured on the palate [20.67(16.06) N] was significantly lower than that for the control group (P<.001), overdentures supported by 2 Locator attachments (P<.001), and overdentures supported by 4 Locator attachments when the distance between the anterior and posterior implants was 8 mm P=.006). CONCLUSIONS: The distribution of implants had a significant effect on the force measured on the palate of the oral analogue in overdentures retained by Locator attachments. When the distance between the 4 implants was 16 or more mm, the load was not significantly lower than the 8 implant design, suggesting that the palate of a 4 implant-retained overdenture with a distance of 16 mm or more, does not contribute significantly to the load transfer to underlying hard palate in the in vitro analogue evaluated.

Effect of axial wall modification on the retention of cement-retained, implant-supported crowns.

STATEMENT OF PROBLEM: Compromised angulation of implants may result in abutment preparation that is less than ideal. Compromised abutment preparation may affect the retention of implant-retained crowns. PURPOSE: The purpose of this study was to investigate the effect of 5 implant abutment designs on the retention of cement-retained crowns by varying the number and position of the axial walls. MATERIAL AND METHODS: Five prefabricated abutments were attached to an implant analog and embedded in an acrylic resin block. The first abutment was left intact without modification. Axial walls were partially removed from the remaining abutments to produce abutments with 3 walls, 2 adjacent walls, 2 opposing walls, and 1 wall. Five crowns were made for each group. The screw access channel for the first abutment was completely filled with composite resin and the rest were partially filled. The retentive surface area of each abutment was calculated. Crowns were cemented with zinc phosphate cement. Tensile force was applied to separate the castings from the abutments. Peak load to dislodgment was recorded. A 1-way ANOVA was used to test for a significant difference followed by the Tukey Honestly Significant Difference test (α=.05). RESULTS: The abutment with 2 opposing axial walls had significantly higher retention than that of all other groups (F=149.9, df =24, P<.001). The abutment with 3 walls exhibited the second highest retention and was significantly greater than abutments with 2 adjacent walls, 1, and 4 walls. Abutments with 2 adjacent walls and 1 wall were not significantly different from each other. The unmodified abutment with 4 walls exhibited the lowest retention despite having a large retentive surface area. CONCLUSIONS: The retention of cemented crowns on implant abutments is influenced by the number and position of axial walls.

The effect of denture cleansing solutions on the retention of pink locator attachments after multiple pulls: an in vitro study.

PURPOSE: The effect of denture cleansing solutions and multiple pulls on the retention of pink Locator patrices was studied. MATERIALS AND METHODS: Five groups of pink Locator attachments (3.0 lb. Light Retention replacement patrix attachments; five in each group) were soaked for the equivalent of 6 months of clinical use in the following solutions: water (control), Efferdent, Polident Overnight, 6.15% sodium hypochlorite (NaOCL, 1:10 dilution), and Listerine mouthwash. A universal testing machine set at a 2 in/min crosshead speed was used to perform 548 pulls (548 cycles of insertion and removal). The reduction in load to dislodgement (retention) after the initial pull and the final pull and the percent reduction in retention after 6 months were compared between the groups using a one-way ANOVA followed by Tukey's Honestly Significant Difference (HSD) Test (α= 0.05). RESULTS: Denture cleansing solutions significantly reduced the retentive values of pink Locator attachments after the initial pull (F = 17.435, p < 0.0001). The retentive values of Efferdent, Listerine, Polident Overnight, and water were significantly higher than the retentive value of the attachments soaked in NaOCl. After 6 months of simulated use (548 pulls), the four denture cleansing solutions had significant effects on the retentive values of pink Locator attachments (F = 5.855, p = 0.003). The retentive values for attachments soaked in NaOCl (7.29 ± 1.0 N) were significantly lower than those of attachments soaked in Listerine (15.82 ± 4.7 N) and in Polident Overnight (14.41 ± 3.6 N). These cleansing solutions also had a significant effect on the percentage of retention lost (F = 3.271, p = 0.032). The loss of retention in attachments soaked in Listerine (29 ± 9%) was significantly lower than attachments soaked in water (53 ± 12%). The loss of retention in attachments soaked in Efferdent was 49 ± 9%; in Polident Overnight, 34 ± 18%; and in NaOCl, 42 ± 11%. There was no significant difference in the percentage of retention loss between water, Efferdent, NaOCl, and Polident Overnight. There was also no significant difference in the percentage of retention loss between Efferdent, NaOCl, Polident Overnight, and Listerine. CONCLUSION: NaOCl significantly decreased the retentive value of Locators. Therefore, it should not be routinely recommended for use as a denture cleanser. Listerine significantly increased the retention of the Locator attachments; however, it is premature to recommend Listerine for use as a denture cleanser.

Comparison of cutting efficiencies between electric and air-turbine dental handpieces.

STATEMENT OF PROBLEM: Dentistry is gravitating toward the increased use of electric handpieces. The dental professional should have sufficient evidence to validate the switch from an air-turbine handpiece to an electric handpiece. However, there is little research quantifying the cutting efficiency of electric and air-turbine handpieces. Studies that do quantify cutting efficiency typically do so with only a single material. PURPOSE: The purpose of this study was to compare the cutting efficiency of an electric handpiece and an air-turbine handpiece, using various materials commonly used in dentistry. MATERIAL AND METHODS: Seven materials: Macor (machinable glass ceramic), silver amalgam, aluminum oxide, zirconium oxide, high noble metal alloy, noble metal alloy, and base metal alloy, were each cut with a bur 220 times; 110 times with an electric handpiece, and 110 times with an air-turbine handpiece. The weight difference of the material was calculated by subtracting the weight of the material after a cut from the weight of the material before the cut. The cutting efficiency was calculated by dividing the weight difference by the duration of the cut (g/s). Data were analyzed by a 2-way analysis of variance followed by Tukey's Honestly Significant Difference (HSD) test (alpha=.05). RESULTS: The electric handpiece cut more efficiently than the air-turbine handpiece (F=3098.9, P<.001). In particular, the high noble metal alloy, silver amalgam, and Macor were cut more efficiently with the electric handpiece (0.0383 +/-0.0002 g/s, 0.0260 +/-0.0002 g/s, and 0.0122 +/-0.0002 g/s, respectively) than with the air-turbine handpiece (0.0125 +/-0.0002 g/s, 0.0142 +/-0.0002 g/s, and 0.008 +/-0.0002 g/s, respectively). CONCLUSIONS: The electric handpiece is more efficient at cutting various materials used in dentistry, especially machinable glass ceramic, silver amalgam, and high noble alloy, than the air-turbine handpiece.

The effect of denture cleansing solutions on the retention of pink Locator attachments: an in vitro study.

PURPOSE: To evaluate the changes in retention of pink Locator attachments after exposure to various denture cleansers. MATERIALS AND METHODS: Six groups (20 pairs each) of pink Locator attachments (3.0 lb. Light Retention replacement patrix attachments) were soaked for the equivalent of 6 months of clinical use in the following solutions: Water (control), Polident Regular, Efferdent, 6.15% sodium hypochlorite (NaOCL, 1:10 dilution), Polident Overnight, and Cool Mint Listerine mouthwash. A universal testing machine set at a crosshead speed of 2 in/min was used to perform one pull. The peak load-to-dislodgement was recorded to reflect changes in the retention of the Locator attachments after soaking. Data were analyzed by one-way ANOVA followed by Tukey's Honestly Significant Difference test. A p< or = 0.05 was considered significant. RESULTS: Denture cleansing solutions significantly affected the retentive values of pink Locator attachments (F = 344.3, p< or = 0.0001). Cool Mint Listerine mouthwash increased the retentive values of the attachments (51.10 +/- 5.31 N) when compared to the control group (45.25 +/- 3.49 N). There was no significant difference in the retentive values of attachments soaked in Polident Regular or Polident Overnight when compared to the control group. Efferdent caused a small reduction in the retentive values (40.81 +/- 2.56 N) and most importantly, diluted NaOCl caused a large reduction in the retentive values (7.83 +/- 2.50 N) of pink Locator attachments. In addition, Cool Mint Listerine mouthwash caused blue discoloration of the Locator attachments, and NaOCl caused whitening and softening of the pink Locator attachments. CONCLUSION: Cool Mint Listerine and Efferdent's small effect on the retentive values of the Locators might be clinically unimportant; however, NaOCl caused a large reduction in the retentive values of the attachments. Because of their effect on retentive values and on the color of the Locator attachments, NaOCl and Cool Mint Listerine are not recommended. These results should be interpreted clinically with caution, realizing that different results may be obtained when fatigue stress during function and multiple pulls (in vivo) are combined with the chemical action of denture cleansers.

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.

The change in retentive values of locator attachments and hader clips over time.

PURPOSE: The aim of this study was to examine early changes in retentive values of implant overdenture attachments during multiple pulls. MATERIALS AND METHODS: Two implant attachment systems (Hader bar and clip, Locator system) were used in this study. The experimental groups were divided into yellow Hader clips, white Locator attachments, and green Locator attachments. Each group consisted of 21 matrix attachments. The attachments were placed into a custom-made acrylic resin block seated passively on another acrylic block containing a Hader bar or two Locator abutments with different angulations. Each attachment was subjected to 20 consecutive pulls using a universal testing machine. The peak load-to-dislodgement of the attachments after each pull was documented, and the percent reduction of the peak load-to-dislodgement was calculated. One-way ANOVA and Tukey's honestly significant difference test were used for data analyses. A p < or = 0.05 was considered significant. RESULTS: There was a significant difference in the percent reduction in peak load-to-dislodgement between the attachments after the first pull (p= 0.005) and after the final pull (p= 0.0001). The yellow Hader clips exhibited the least percent reduction in peak load-to-dislodgement (6.50 +/- 3.59%) after the first pull, followed by the white Locator attachments (8.60 +/- 4.42%); the green Locator attachments exhibited the greatest reduction (11.05 +/- 4.94%). CONCLUSION: The results of this in vitro study demonstrate that retentive values of the Locator attachments are reduced significantly after multiple pulls. Although this reduction might not be noticeable to the patient, it is recommended that the clinician place and remove the overdenture multiple times before delivery.

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.

Effect of Mutans streptococcal colonization on plaque formation and regrowth in young children--a brief commnunication.

OBJECTIVES: Visible plaque on the maxillary anterior teeth of young children has been identified as a risk indicator for early childhood caries. The present study examined whether this plaque is related to the colonization of children's teeth with Mutans streptococci (MS) or toothbrushing frequency. METHODS: Thirty-nine children, aged 12 to 36 months, had plaque scores, and plaque samples were taken from the labial surfaces of the maxillary incisors at baseline and repeated 3 days after suspended oral hygiene (plaque regrowth). RESULTS: A positive correlation was found between the baseline percent MS and regrowth plaque score and between baseline and regrowth plaque scores. Plaque scores of those that brushed zero to one time a day were not different from those who brushed two or more times a day. CONCLUSIONS: This study suggests that the presence of plaque on the anterior teeth of young children is consistent and related to MS colonization.

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.