Dental caries history in nine children with chromosome 18p deletion syndrome.

Chromosome 18p deletion syndrome is caused by the deletion of a portion of genetic material on the short (p) arm of chromosome 18. Many of 100 prior case reports in the medical literature describing the dental health of subjects with this syndrome reported multiple caries associated with the syndrome. At the third annual international conference of The Chromosome 18 Registry & Research Society, dental examinations were carried out on nine children with chromosome 18p deletion syndrome and five of their unaffected siblings. The dental examination included an intra-oral evaluation of coronal decay and filled permanent teeth surfaces (DFS) and decayed and filled primary tooth surfaces (dfs) using a mouth mirror, explorer, and a high-intensity fiber optic light. An evaluation of the data revealed that five of nine children with 18p deletion syndrome (56%) were free of tooth decay or a history of tooth decay. Four of the nine (44%) had tooth decay or a history of tooth decay. The prevalence of decay was quite similar in the genetically unaffected siblings. Three of the five (60%) unaffected siblings of the children with 18p were free of tooth decay, whereas two of the five (40%) had tooth decay. One of the affected children had a missing mandibular left central incisor. None of the children had abnormally shaped teeth. The caries pattern seems to be similar to that reported in the NHANES III data collected in the United States from 1988-1991. Analysis of these preliminary data suggests that the risk for caries in chromosome 18p deletion syndrome may be lower than previously reported.

The use of resin composite pins to improve retention of Class IV resin composite restorations.

This study evaluated the effect of an intracoronal resin composite pin on Class IV resin composite restorations. A control group of 16 bovine teeth was prepared with standardized conventional Class IV preparations. For an experimental group, 16 similar Class IV preparations were made, with the addition of an intracoronal pin channel prepared with a #330 bur into the dentin. All specimens were restored with Herculite XRV and OptiBond according to the manufacturer's recommendations. After one week, specimens were placed in an Instron Universal Testing Machine and loaded at 90 degrees to the long axis until the restorations failed. Results indicated that the mean fracture load of the Class IV restoration group, with the resin composite pin, was 36% higher than the conventional Class IV group (p = 0.02). An intracoronal resin composite pin may aid the retention and resistance form of complex resin composite restorations.

Effect of powder-free latex examination glove use on airborne powder levels in a dental school clinic.

Cornstarch powder on latex examination gloves acts as an airborne carrier of natural latex allergens resulting in cutaneous, conjunctival, and/or respiratory responses to latex, a particular concern in a dental school environment where concentrated use of latex examination gloves occurs. This study measured airborne powder levels associated with a trial substitution of powder-free latex examination gloves for powdered latex examination gloves in a dental school clinic. Secondary aims of the study were to assess user acceptance of powder-free gloves during the trial and to assess the financial impact of converting the entire dental school to a powder-free environment. Air was sampled from two areas (dispensary and treatment room) of a student clinic fifteen to thirty minutes before the beginning of normal clinic sessions and again about 1.5 hours into the clinic session. The samples were microscopically analyzed for particulate counts of cornstarch powder. A written survey instrument assessed user acceptance of the two types of gloves. Historical financial data were used to estimate the cost of converting the entire dental school to a powder-free environment. Both the dispensary and the treatment room showed significant reductions in airborne powder counts during use of powder-free latex gloves and a return to high powder counts with resumption of powdered glove use. During the weeks of powdered glove use, the powder counts were also significantly lower before the beginning of the clinic session and higher during the clinic session. User acceptance of the powder-free latex gloves was high. The increased cost per year to convert the entire dental school to a powder-free environment was estimated to be $13,943.

Repairability of three resin-modified glass-ionomer restorative materials.

The purpose of this study was to evaluate the repair shear bond strengths of three resin-modified glass-ionomer restorative materials repaired at two different times. Thirty specimens of Fuji II LC, Vitremer, and Photac-Fil were prepared in cavities (2 mm x 7 mm) cut into acrylic resin cylinders. After the initial fill, half of the specimens were repaired 5 minutes later and half 1 week later. The specimens were stored in 37 degrees C distilled water when not being repaired or tested. Repairs were made without any surface preparation of the initial fill. Each specimen was mixed according to the manufacturer's directions, placed in the preparation in 1-mm increments and photocured for 40 seconds. The last increment was covered with a plastic strip and a glass slide before curing to create a smooth surface. Repairs were accomplished by drying the specimen for 10 seconds, then adding the new material to the unprepared surface using a 3-mm-thick polytetrafluoroethylene mold. The specimens were thermocycled 500 times, stored in 37 degrees C distilled water for 1 week, then loaded to failure in shear at a rate of 0.5 mm/min. Data were analyzed using a one-way ANOVA and Z-value multiple comparison test to determine significant differences at the 0.05 significance level. Vitremer showed no significant difference in shear bond strength for 5-minute and 1-week repair periods, while Fuji II LC and Photac-Fil did. Repair bond strength of Vitremer was significantly greater than Fuji II LC and Photac-Fil at both repair times. This study showed that time of repair significantly affected the bond strength of two of the materials tested.

Early fracture resistance of amalgapin-retained complex amalgam restorations.

Amalgapins are susceptible to early fracture during matrix removal and carving. The purpose of this study was to examine the early fracture resistance of amalgapin-retained restorations using a spherical amalgam alloy, an admixed amalgam alloy, a combination of admixed alloy over the spherical alloy, and a recently introduced modified spherical amalgam alloy. Four amalgapin channels with a diameter of 1.4 mm and depth of 2 mm were prepared in cylinders of Macor, a machinable ceramic material. The amalgapins were hand condensed, and the bulk of the restoration was mechanically condensed. In the group using the combination of alloys, 800 mg of spherical alloy was condensed into the amalgapins and over the floor of the preparation. The admixed alloy was then condensed over the spherical alloy to build up the bulk of the restoration. Using an Instron Universal Testing Machine, the restorations were tested to shear failure at an average of 15.8 +/- 1.3 minutes after the initiation of trituration of the amalgam alloy. A metal ring was placed around the restoration and pulled 90 degrees to the long axis to simulate matrix band removal. Data were analyzed using Kruskal-Wallis procedures. The fracture resistance of the spherical alloy group and the spherical/admixed group were significantly higher than admixed or Tytin FC. All fractures occurred in amalgam at the entrance to the amalgapin channel. The combination of spherical and admixed amalgam alloys in a restoration may reduce the potential for early dislodgment while allowing additional time for carving.

Effects of surface treatments on amalgam repair.

Dentists are faced with clinical situations that require the decision to replace or repair an amalgam restoration. The purpose of this study was to compare five amalgam repair techniques. Six groups of 15 amalgam beams each were fabricated by mechanical condensation of Tytin into an anodized aluminum split mold. Specimens were aged for 7 days prior to repair. Repaired specimens were stored for 7 days and thermocycled 500 times. Repair strength was measured by transverse strength testing in an Instron testing machine. Data were analyzed by a one-way ANOVA and a Student-Newman-Keuls test at the P < or = 0.05 level. The surface treatments were: Group A) intact beams, B) roughened with a #557 bur, C) air abraded with 50 microns aluminum oxide, D) retentive undercuts with a #33 1/2 bur, E) Amalgambond Plus, and F) no treatment. The repair strength of the various experimental groups ranged from 7-18% of the intact specimens. The #557 bur-roughened group yielded statistically higher repair strengths than all other surface treatments, which were statistically equivalent to each other.

A diagnostic comparison of panoramic and intraoral radiographs.

OBJECTIVE: This study compared panoramic and intraoral radiographic surveys in the evaluation of specific dental pathoses in Air Force personnel. STUDY DESIGN: The radiographs of 30 subjects were read singly and in various combinations: panoramic survey only; periapicals plus bitewings; panoramic survey plus bitewings; and panoramic survey plus periapicals plus bitewings. Three independent, blinded examiners using standardized viewing conditions assessed the radiographs in random order for the presence of caries, periapical pathoses, bone loss, furcation involvement, impacted/unerupted teeth, internal/external root resorption, and retained roots. The consensus radiographic standard of true pathosis was the simultaneous interpretation by the three examiners of all radiographs for each subject. RESULTS AND CONCLUSIONS: The panoramic survey by itself was shown to have the lowest correlation with the consensus radiographic standard when basic military trainees with generalized dental pathoses were evaluated. The combination of panoramic survey plus bitewing radiographs exhibited a diagnostic yield for specific pathoses that was comparable to that of panoramic survey plus bitewings plus periapicals.

Perioperative use of 0.12% chlorhexidine gluconate for the prevention of alveolar osteitis: efficacy and risk factor analysis.

OBJECTIVES: The purposes of this study were to evaluate the use of 0.12% chlorhexidine gluconate as a prophylactic therapy for the prevention of alveolar osteitis and to further examine subject-based risk factors associated with alveolar osteitis. STUDY DESIGN: The trial was a randomized, double-blind, placebo-controlled, parallel-group study conducted among 279 subjects, each of whom required oral surgery for the removal of a minimum of one impacted mandibular third molar. Subjects were instructed to rinse twice daily with 15 ml of chlorhexidine or placebo mouthrinse for 30 seconds for 1 week before and 1 week after the surgical extractions. This regimen included a supervised presurgical rinse. Alveolar osteitis diagnosis was based on the subjective finding of increasing postoperative pain at the surgical site that was not relieved with mild analgesics, supported by clinical evidence of one or more of the following: loss of blood clot, necrosis of blood clot, and exposed alveolar bone. RESULTS: In comparison with use of the placebo mouthrinse, prophylactic use of the chlorhexidine mouthrinse resulted in statistically significant (p < 0.05) reductions in the incidence of alveolar osteitis. With chlorhexidine therapy, the subject- and extraction-based incidences of alveolar osteitis in the evaluable subset (271 subjects) were reduced, relative to placebo, by 38% and 44%, respectively. The corresponding odds ratios that describe the increased odds of experiencing alveolar osteitis in the placebo group were 1.87 and 2.05 for subject- and extraction-based analyses, respectively. In comparison with nonuse of oral contraceptives, the use of oral contraceptives in female subjects was related to a statistically significant increase in the incidence of alveolar osteitis (odds ratio = 1.92, p = 0.035). Relative to male subjects, the observed incidence of alveolar osteitis for female subjects not using oral contraceptives was not statistically significant (odds ratio = 1.18, p = 0.64). Smoking did not increase the incidence of alveolar osteitis relative to not smoking (odds ratio = 1.20, p = 0.33). CONCLUSIONS: These data confirm that the prophylactic use of 0.12% chlorhexidine gluconate mouthrinse results in a significant reduction in the incidence of alveolar osteitis after the extraction of impacted mandibular third molars. In addition, oral contraceptive use in females was confirmed to be a risk factor for the development of alveolar osteitis.

A perceptibility curve comparison of Ultra-speed and Ektaspeed Plus films.

OBJECTIVE: The purpose of this study was to evaluate the subjectively assessed contrast difference between Kodak's Ultra-speed and Ektaspeed Plus dental radiography films (Eastman Kodak, Rochester, N.Y.) through the use of perceptibility curves. DESIGN: Four series of 22 radiographs were exposed at 70 and 90 kVp with each film type by means of a Gendex 1000 dental radiography unit (Gendex Corp., Milwaukee, Wis.) for times ranging from 0.05 to 5 seconds at 10 ma. The test object consisted of a 7-mm-thick rectangular aluminum block with 10 circular depth cuts, each 2 mm in diameter, which created wells varying in depth from 50 to 500 microns. The corresponding films were processed concurrently (for 4.5 minutes) in total darkness with fresh Kodak Readymatic solutions (Eastman Kodak) held at a constant temperature of 28 degrees C. The resulting radiographs were viewed in a predetermined random order under ideal conditions by 10 dentists. The evaluators recorded the maximum number of perceptible images on each film. A pair of perceptibility curves were generated at 70 and 90 kVp by plotting the log relative exposure versus the mean number of perceptible images. RESULTS: There was no statistical difference between the two film types with respect to the mean number of perceptible images, as analyzed by Wilcoxon's signed rank test (p = 0.22; p = 0.44). CONCLUSIONS: There is no subjectively assessed contrast difference between Kodak s Ultra-speed and Ektaspeed Plus films at 70 and 90 kVp.

Prevalence of occupationally related hand dermatitis in dental workers.

Occupationally related hand dermatitis has been attributed to frequent hand-washing, exposure to possible sensitizers and latex glove use. The authors conducted a study to determine the prevalence of occupationally related hand dermatitis in dental personnel. They found that 75 (19.2 percent) of 390 subjects self-reported they had a positive history of hand dermatitis. Further testing of 53 of these subjects indicated that only 9.4 percent reacted to the 45 allergens tested, and 3.8 percent had an allergy to latex.

Computer-assisted densitometric image analysis (CADIA) of previously sealed carious teeth: a pilot study.

Previous studies have shown that occlusal dental caries can be arrested with sealants. Radiographic monitoring must be performed to ensure success. Standardized sequential bitewing radiographs over a 10-year interval of four patients who had sealed composite restorations placed without caries removal were digitized and analyzed using the CADIA algorithm. CADIA values for the 10-year period were analyzed using Analysis of Variance (ANOVA), and showed no significant change in radiographic density for this interval (P > 0.05), which is suggestive of arrested dental caries.

In vitro microleakage of etched and rebonded Class 5 composite resin restorations.

The purpose of this study was to measure the effect rebonding, with and without etching restoration margins, had on the microleakage of class 5 composite restorations. Eighty-two class 5 composite restorations were placed in extracted human molars with one margin on etched enamel and one below the cementoenamel junction. After finishing with disks, the teeth were divided into seven margin treatment groups: 1) restorations with no rebonding (control), 2) restoration margins rebonded with Universal Bond 3 primer, 3) restoration margins etched with 37% phosphoric acid and rebonded with Universal Bond 3 primer, 4) restoration margins rebonded with Universal Bond 3 adhesive, 5) restoration margins etched and rebonded with Universal Bond 3 adhesive, 6) restoration margins rebonded with Fortify, and 7) restoration margins etched and rebonded with Fortify. After storage in a chlorine-based disinfectant for 1 week, the restorations were thermocycled and then soaked in dye. After sectioning, microleakage was assessed by measuring the extent of dye penetration along the restoration-tooth interface. At the enamel margins there was no statistical difference in microleakage rebonded with or without etching. On the gingival margins there was a statistically significant reduction in microleakage for the nonetched Universal Bond 3 adhesive rebonded group compared to the nonrebonded control.

Effect of triturator speed variation on physical properties of encapsulated glass-ionomer luting cements.

This in vitro study evaluated the effect of variation of triturator mixing speed on the physical properties of two encapsulated glass-ionomer luting cements. Physical properties evaluated were working time, setting time, film thickness, and 24-hour and 7-day compressive strengths. Encapsulated glass-ionomer luting cements were mixed at 3000, 3500, 4000 (control), and 4500 cycles per minute (cpm). An oscillating rheometer was used to determine working and setting times. Film thickness and compressive strength were determined using methods described in ANSI/ADA Specification No 66 for dental glass-ionomer cements. Results of the study indicated that decreased mixing speed may prolong working and setting times for Ketac-Cem Maxicap and Fuji Cap I. Within the range of 3500 to 4500 cpm, variations in mixing speed do not significantly affect compressive strength or film thickness values for either cement. Excessively slow mixing speed (3000 cpm) often resulted in the presence of unmixed powder expressed from the capsule nozzle prior to the expression of mixed cement. The presence of this unmixed powder results in a decreased powder/liquid ratio, which may have an adverse effect on the physical properties of the set cement.

Effect of thermocycling on the microleakage of conventional and resin-modified glass ionomers.

PURPOSE: To compare the effect of thermocycling on the microleakage of conventional and resin modified glass ionomer restorative materials. MATERIALS AND METHODS: Class V preparations, centered on the CEJ, were prepared on the lingual and facial surfaces of 30 extracted human third molar teeth. Preparations were conditioned and restored randomly on one surface with Ketac-Fil and on the other surface with Photac-Fil. Restorations were protected during curing, finishing, and storage with Ketac-Glaze. Specimens were aged in room temperature distilled water for 7 days. Half of the specimens were thermocycled for 2,500 cycles in 5 degrees-55 degrees water baths with 5-second dwell times. All specimen apices were sealed with red compound, occlusal fissures sealed with pit/fissure sealant, and surfaces painted to within 1.5 mm of restoration margins with red nail polish. Specimens were stained with 5% methylene blue, invested in orthodontic resin, and sectioned faciolingually. The percentage of dye penetration along the tooth restoration interface was measured with a digital imaging system. RESULTS: Statistical analysis showed that neither thermocycling or type of material had a significant effect on dye penetration (P > 0.5).

Examination of a resin-modified glass-ionomer material as a pit and fissure sealant.

The purpose of this in vitro study was to examine the effect of various powder-liquid ratios of an experimental resin-modified glass-ionomer polymer cement on dye penetration when the cement was used as a pit and fissure sealant. Eighty extracted human third molars were randomly assigned to one of four pit and fissure sealant conditions: a resin-based sealant or one of three variations in powder-liquid ratios (1.4:1.0, 1.8:1.0, and 2.0:1.0) of an experimental, light-activated, resin-modified glass-ionomer cement. After sealant placement, the teeth were thermocycled and immersed in methylene blue dye. The teeth were sectioned, and the extent of dye penetration along the sealant-enamel interface was measured linearly. The resin-sealed occlusal fissures showed statistically significantly less dye penetration than did the three powder-liquid ratios of the experimental resin-modified glass-ionomer-cement sealant.

Effect of dentin moisture and storage time on resin bonding.

PURPOSE: To evaluate the effects of dentin moisture and two different storage times on the shear bond strength of resin composite bonded to dentin with Scotchbond Multi-Purpose Adhesive. MATERIALS AND METHODS: The occlusal surfaces of 60 extracted human molars were reduced to provide flat dentin surfaces. After being hand-finished using wet 400- and 600-grit SiC papers, the teeth were randomly divided into four groups of 15 specimens each. The teeth were etched, rinsed, and then either blotted with gauze which left a visibly moist surface or dried with compressed air. The primer and adhesive were applied according to the manufacturer's instructions and resin composite cylinders were bonded to the teeth. Two of the groups (one moist, one dry) were stored for 24 hours in 37 degrees C distilled water while the other two groups were stored for 90 days in 37 degrees C distilled water. At the end of their storage times, the specimens were loaded to failure in shear at 0.5 mm/minute. RESULTS: Mean bond strength values and standard deviations in MPa were: Dry dentin at 24 hrs, 13.30 +/- 5.1; Dry dentin at 90 days, 13.07 +/- 3.8; Moist dentin at 24 hours, 13.64 +/- 4.9; Moist dentin at 90 days, 15.58 +/- 5.3. No statistically significant differences were found for bond strengths to dry and to moist dentin for either storage time. Time had no significant effect for either the dry dentin group or the moist dentin group.

Saliva contamination of dentin bonding agents.

This study examined the shear bond strength to dentin of two dentin bonding agents when contaminated with a measured amount of saliva at various stages in their application procedure. Eighty extracted human third molar teeth were randomly separated into four groups of 10 for each of the dentin bonding systems tested (All-Bond 2, Scotchbond Multi-Purpose). Group A specimens were not contaminated; primer/adhesive/resin were applied according to manufacturers' instructions. In Group B, samples were contaminated for 15 seconds with fresh whole human saliva, and then forcibly dried with a blast of oil-free air; this occurred after application of the primer but prior to application of adhesive. In Group C, contamination occurred after application of adhesive, prior to application of resin. In Group D, saliva was allowed to contaminate the surface as the primer was being applied, without forcible removal. Specimens were then thermocycled, mounted, and tested in shear on an Instron at 7 days. Bond strengths in MPa were obtained, and data were analyzed using a one-way ANOVA, at the P = 0.05 level of significance. Although shear bond strengths were lowered in saliva-contaminated samples, there was no statistically significant difference between group means.

The effect of various bases on the fracture resistance of amalgam.

UNLABELLED: This study compared the compressive force required to fracture amalgam over nine base materials: a calcium hydroxide product (Dycal); two autocured glass ionomers (GlasIonomer Base Cement and Ketac-Bond); three light-cured glass ionomers (Photac-Bond, Variglass VLC, and Vitrebond); two light-cured resins (Timeline and VLC Dycal); and a zinc phosphate cement (Fleck's Zinc Cement). For the control group, 10 aluminum dies (25 mm x 12 mm x 10 mm) were milled with 3.0 mm x 3.0 mm slots, which were filled with hand-condensed Tytin amalgam with no underlying base. For experimental groups, 10 aluminum dies of equal dimension were milled with 3.5 mm x 3.0 mm slots. Following manufacturer's instructions, the nine base materials were successively placed in these 10 dies using a depth-limiting device made of light-transmitting clear acrylic to ensure a 0.5 mm thickness, and Tytin amalgam was again condensed over each base such that the depth of the amalgam equalled that in the control. All test specimens were stored in 100% humidity for 48 hours then fractured in compression on an Instron machine. Mean force, in Newtons (S D in parentheses), required to fracture the specimens was: CONTROL: 1934(210), Zinc Cement: 1874(147), GlasIonomer Base Cement: 1839(174), Ketac-Bond: 1723(225), Vitrebond: 1485(155), Photac-Bond: 1422(294), Advanced Formula II Dycal: 1296(237), VLC Dycal: 1035(116), Variglass: 909(294) and Timeline: 906(275). ANOVA and Student-Newman-Keuls statistical analysis (alpha = 0.05) indicated that the autocuring glass ionomers, GlasIonomer Base Cement and Ketac-Bond, and a zinc phosphate cement, Zinc Cement, provided significantly more fracture resistance for amalgam than the other bases tested and were not statistically different from a no-base control.

Ceramic bracket bonding: a comparison of shear, tensile, and torsional bond strengths of ceramic brackets.

The purpose of this study was to evaluate whether shear, tensile, or torsional forces were best suited for debonding ceramic brackets. Four commercially available ceramic brackets were evaluated. The brackets included both polycrystalline and monocrystalline types with either chemical or mechanical retention in the bracket bases. The ceramic brackets were bonded to one hundred and twenty bovine teeth, using Concise. The brackets were stressed until bond or bracket failure occurred with either shear, tensile, or torsional forces on the Instron machine. The maximum bond strength and the site of bond failure was recorded. Starfire TMB brackets fractured 30% of the time during shear debonding, whereas, Quasar 1000, Lumina, and Transcend 2000 brackets exhibited no bracket fractures. The shear bond strengths of Quasar 1000 brackets were significantly higher than Starfire TMB brackets. Starfire TMB was the only bracket type that exhibited no bracket fractures with tensile force. Tensile bond strengths were not significantly different between the four bracket types. In torsion, Lumina was the only bracket type that did not exhibit any bracket failures. Shear and tensile bond strengths of chemically retained brackets were not significantly different than mechanically retained brackets. Torsional bond strength of chemically retained brackets was significantly higher than mechanically retained brackets. The results suggest Quasar 1000, Lumina, and Transcend 2000 are best removed with shear or tensile forces. Starfire TMB is best removed with tensile forces.

Amalgam in the restoration of posterior teeth.

The use of aesthetic restorative materials such as cast ceramic, porcelain, and composite resin for the restoration of posterior teeth has increased in recent years, but amalgam remains the most frequently used material. Although stories in the media recently renewed the debate over amalgam safety, amalgam has remained in the armamentarium of the average clinician in large part because of its long positive clinical history, beneficial physical properties, and forgiving handling characteristics.