Colloids of detonation nanodiamond particles for advanced applications.

Nanodiamond (ND) is one of the most attractive allotropic modification of carbon due to their unique physical and chemical properties. In the present review the current state of science and technology in the field of NDs is analyzed. ND can be used in various application and in different form e.g. as a dispersion phase in suspension, as a filler in composites, etc., so the sedimentation stability of ND in different media are under scrutiny. Thus, theoretical aspects of ND suspension coagulation mechanisms and the methods avoiding it were considered. The dependence of rheological behavior on particles modification was discussed as well. Various methods for the preparation and modification of NDs to obtain particles of various sizes on a nanometer scale with different physicochemical properties were reviewed. The area of practical application for NDs was considered on the example of polymer composites. The various manufacturing methods, mechanical properties and medical aspects for thermosetting, thermoplastic and elastomer ND composites were summarized.

The strong thermoelectric effect in nanocarbon generated by the ballistic phonon drag of electrons.

The thermoelectric power and thermoelectric figure of merit for carbon nanostructure consisting of graphite-like (sp(2)) and diamond-like (sp(3)) regions have been investigated. The probability of electron collisions with quasi-ballistic phonons in sp(2) regions has been analysed for the first time. We have shown that the probability is not small. We have analysed the influence of various factors on the process of the electron-ballistic phonon drag (the phonon drag effect). The thermoelectric power and thermoelectric figure of merit under conditions of ballistic transport were found to be substantially higher than those in the cases of drag by thermalized phonons and of electron diffusion. The thermoelectric figure of merit (ZT) in the case of a ballistic phonon contribution to the phonon drag of electrons should be 50 times that for chaotic phonons and 500 times that in the case of the diffusion process. In that case ZT should be a record (ZT≥2-3).

Oral findings and periodontal status in children, adolescents and young adults suffering from renal failure.

AIM: Describe the oral condition of chronic renal failure and healthy subjects, and the relationship between oral variables, chronic renal failure (CRF) conditions, and their treatment. MATERIALS AND METHODS: Four renal failure groups: chronic renal disease (n=22); undergoing dialysis (n=22); after dialysis and transplant (n=21); and after transplant (n=32), and a healthy control (n=38) were examined. Caries, enamel hypoplasia, pulp obliteration, plaque index, gingival bleeding, recession, overgrowth and index, probing depths, attachment loss, renal treatments and their relations with the oral variables were analysed. RESULTS: The renal failure groups had higher gingival index (GI) and bleeding, probing depths, attachment loss, hypoplasia and obliteration and less caries, than the control. Plaque was higher in the dialysis and pre-dialysis (PD) groups. Overgrowth was evident after transplant. The PD group showed lower GI than other renal groups. Dialysis duration and end-stage renal failure significantly correlated with gingivitis, probing depth, attachment loss and enamel hypoplasia. Immuran correlated positively with probing depth, gingival recession and attachment loss. Normiten and Nifedipine had positive correlations with gingival overgrowth. CONCLUSIONS: CRF patients are characterized by pulp obliteration, gingival and periodontal diseases. Duration of end stage renal failure and type of systemic treatment have a significant influence on the oral condition.

Mineral trioxide aggregate vs. formocresol in pulpotomized primary molars: a preliminary report.

PURPOSE: The aim of this study was to compare the effect of mineral trioxide aggregate (MTA) to that of formocresol (FC) as pulp dressing agents in pulpotomized primary molars with carious pulp exposure. METHODS: Forty-five primary molars of 26 children were treated by a conventional pulpotomy technique. The teeth were randomly assigned to the MTA (experimental) or FC (control) group by a toss of a coin. Following removal of the coronal pulp and hemostasis the pulp stumps were covered with an MTA paste in the experimental group. In the control group, FC was placed with a cotton pellet over the pulp stumps for 5 minutes and removed; the pulp stumps were then covered by zinc oxide-eugenol (ZOE) paste. The teeth of both groups were restored with stainless steel crowns. Eighteen children with 32 teeth arrived for clinical and radiographic follow-up evaluation ranging from 6 to 30 months. RESULTS: The follow-up evaluations revealed only one failure (internal resorption detected at a 17 months postoperative evaluation) in a molar treated with formocresol. None of the MTA-treated teeth showed any clinical or radiographic pathology. Pulp canal obliteration was observed in 9 of 32 (28%) evaluated molars. This finding was detected in 2 out of the 15 teeth treated with FC (13%) and in 7 out of the 17 treated with MTA (41%). CONCLUSION: MTA showed clinical and radiographic success as a dressing material following pulpotomy in primary teeth and seems to be a suitable replacement for formocresol in primary teeth.

Dental health behavior of children with BBTD treated using general anesthesia or sedation, and of their parents in a recall examination.

The aim of the study was to assess the dental status and dental health behavior of children with Baby Bottle tooth Decay treated using general anesthesia or sedation, and the dental health behavior of their parents in a recall examination. The study population consisted of sixty-five children, among whom thirty-four were treated using general anesthesia and thirty-one using sedation. The recall examination included a full dental examination from which the children's dif index could be drawn. Loe's plaque index was used to assess the amount of plaque on the teeth. Sociodemographic information and the dental health behavior of the parents and children were obtained. Plaque index was similar in the general anesthesia and sedation groups. The parents of the general anesthesia group were younger than the parents of the sedation group (35.0 +/- 6.7 and 38.8 +/- 6.2 for the fathers, and 32.4 +/- 5.9 and 34.9 +/- 5.3 for the mother, respectively). More firstborn children were treated using general anesthesia than using sedation. Significantly more siblings were treated in the sedation group. Children treated using sedation had significantly more siblings treated in the same mode. Parents of the children in the general anesthesia group were significantly more involved in brushing their children's teeth than the other group. In the sedation group, more children brush their teeth without parental help. Significantly more children in the general anesthesia group reduced their sweet consumption than in the sedation group. We conclude that preventive behaviors were more frequently adopted among the families of children treated using general anesthesia.

A comparison of restorations for children with early childhood caries treated under general anesthesia or conscious sedation.

PURPOSE: There is no data in the dental literature concerning the quality of the restorations performed in young children with early childhood caries (ECC) under sedation as compared with those treated under general anesthesia (GA). The aim of this study was to compare the quality of restorations and recurrent caries in 65 children with ECC who had dental treatment under GA or sedation. METHODS: Thirty-four children, mean age 34.4 months were treated under GA and 31 children with a mean age of 37.2 months were treated under sedation and re-examined 6-24 months after completion of treatment. The quality of the restorations was evaluated using a modified Cvar & Ryge index. RESULTS: Fifty-nine percent of children treated under GA required further dental treatment compared to 74% of children treated under sedation. The majority of the required treatment was due to new caries: 57% in the GA group and 60% in the sedation group. A total of 248 restorations were evaluated for the GA group, with a 94% success rate for marginal adaptation, 92% success for anatomic form, and 97% had no secondary caries. In the sedation group, out of 224 restorations, 78% demonstrated perfect marginal adaptation, 79% showed adequate anatomic form, and 90% had no secondary caries. Successful marginal adaptation was found in 90% of strip crowns placed under GA, compared to 63% of those placed under sedation. CONCLUSION: It is concluded that the outcome of treatments related to quality of the restorations performed under GA is better for all parameters examined.

Children with baby bottle tooth decay treated under general anesthesia or sedation: behavior in a follow-up visit.

The purpose of the present study was to compare the behaviors of a group of children, who were treated for baby bottle tooth decay (BBTD) under general anesthesia (GA) or under sedation in a dental school environment in a routine follow-up examination, and to assess the dental anxiety levels of the parents. Sixty-five children, who were treated for BBTD in the Pediatric Dentistry clinic of the Hebrew University-Hadassah School of Dental Medicine between 1995-1997 under GA (34 children) or sedation (31 children). The parents of these children agreed to attend our clinic for recall examination 13 months post treatment following a telephone conversation. Frankl's behavioral scale and the sitting pattern were recorded for each child. In the sedation group, Frankl's scores of the present visits were then compared to the scores recorded at the initial examination visit that were obtained from the dental records. The accompanying parents were asked to note the number of visits to the dentist in the past two years, and to complete Corah's dental anxiety scale (DAS). No difference was observed between the children in both groups. Most of the children in the GA and in the sedation groups sat alone on the dental chair, without the assistance of the parents. Parents of the sedation group showed higher scores than the GA group in the total DAS (9.35 and 8.90 respectively), however these differences were not statistically significant. It is concluded that children treated for BBTD under GA or under sedation at a very young age behave similarly in a follow-up examination nearly 13 months postoperatively.

Composite resin support of undermined enamel in amalgam restorations.

PURPOSE: Previous reports suggested that cusp fracture strength increases with the use of bonded composites. The purpose of this study was to assess fracture resistance of undermined cusps, when supported by a layer of bonded composite, in extensive occlusal carious lesions. METHODS: Primary and permanent molars in children that were treated included those with extensive occlusal caries with undermined enamel in one or more cavity walls. Following local anesthesia and rubber dam application, cavity outline was prepared with a #330 tungsten bur, and the carious lesion removed. If an unsupported cusp was present, the inner enamel wall and the dentine floor adjacent to this wall was etched with a gel containing 37% phosphoric acid, rinsed and dried and Scotch bond multipurpose applied; a 1-mm layer of Z100 was applied to the unsupported cusp and polymerized; a nongamma 2 amalgam or Z100 was used to restore the tooth. RESULTS: The children were re-examined after 6, 12 or 24 months. A total of 42 restorations were placed in 39 children (26 boys and 13 girls), ranging in age from 4 to 16 years (mean age 9 years, 6 months). This is a preliminary report on 30 restorations, followed up from 6 to 24 months. All 30 restorations were successful in preventing cuspal fracture. Four teeth developed caries in the proximal surface, but were unrelated to the restoration. CONCLUSIONS: It was concluded that bonded composite can prevent fracture of unsupported cusps.

Clinical performance of esthetic posterior crowns in primary molars: a pilot study.

PURPOSE: The aim of this pilot study was to assess the clinical performance of esthetic crowns and to compare these to conventional stainless steel crowns (SSC). METHODS: Twenty two crowns (11 conventional and 11 esthetic) were placed in mandibular primary molars obeying the following criteria: the tooth was not mobile; no fistulae were present; the tooth had at least one caries free or properly restored antagonist and had to be in contact with one adjacent tooth mesially, in the case of the primary second molars or distally in the case of the primary first molars. Crown preparation was done in a conventional manner, but reduction was more extensive for the thicker esthetic crowns, to allow for proper occlusion. The crowns were evaluated clinically and radiographically after 6 months and the following parameters were assessed: gingival health, marginal extension, crown adequacy, proper position or occlusion, proximal contact, chipping of the facing (for esthetic crowns) and cement removal. RESULTS: At the 6 month evaluation all esthetic crowns were intact, without chipping of the facing, and no excess of cement was observed in both groups. No difference was found for marginal extension, occlusion, proximal contact, crown adequacy, and bone resorption, but a significant difference was found for periodontal health between esthetic crowns and conventional SSC (P < 0.001 McNemar test). CONCLUSIONS: The esthetic crowns assessed had several inconveniences, as they resulted in poor gingival health, are very expensive, and, although not measured, are bulky and without a natural appearance.

Ferric sulfate versus dilute formocresol in pulpotomized primary molars: long-term follow up.

The aim of this study was to compare the effect of ferric sulfate (FS) to that of dilute formocresol (DFC) as pulp dressing agents in pulpotomized primary molars. Ninety-six primary molars in 72 children were treated by a conventional pulpotomy technique. Fifty-eight teeth were treated by a FS solution for 15 sec, rinsed, and covered by zinc oxide-eugenol paste (ZOE). In another 38 teeth, a cotton pellet moistened with 20% DFC was placed for 5 min, removed, and the pulp stumps were covered by ZOE paste. The teeth of both groups were sealed by a second layer of intermediate restorative material (IRM) and restored with a stainless steel crown. This is a report of the clinical and radiographic examination of 55 teeth dressed with FS and 37 teeth fixed with DFC, that have been treated 6 to 34 months previously (mean 20.5 months). Four teeth were excluded from the study due to failure of the patient to present for recall. Success rates of 92.7% for the FS, and of 83.8% for the DFC were not significantly different. Four teeth (7.2%) of the FS group and two (5.4%) of the DFC group presented internal resorption. Inter-radicular radiolucencies were observed in two teeth of the FS group and three teeth of the DFC group. The latter also presented periapical lesions. Success rates of both groups were similar to those of previous studies utilizing the traditional Buckley's formocresol.

Pulp response to ferric sulfate, diluted formocresol and IRM in pulpotomized primary baboon teeth.

This study investigated the pulp response to a 15.5 percent ferric sulfate solution (FS) and a 20 percent dilution of formocresol (DFC) in pulpotomized primary teeth of baboons, after four and eight weeks. Pulpotomies were performed in seventy-nine primary teeth of 4 baboons. After coronal pulp resection, the pulp stumps were painted with ferric sulfate for fifteen seconds, in thirty-two teeth (group 1); in another thirty-two teeth, a cotton pellet moistened with dilution of formocresol was placed over the pulp stumps for five minutes, and removed (group 2). In fifteen teeth, IRM was placed directly over the pulp stumps after hemostasis (group 3--control). The teeth of all groups were sealed with IRM, and examined for inflammatory changes under a microscope by two blinded examiners. Seventy-seven teeth were assessed. Mild or no inflammation was found in 58 percent (18/31) of the teeth of group 1, in 48 percent (15/31) of those of group 2, and in 73 percent (11/15) of those of group 3. Severe inflammation was found in 35 percent (11/31) of group 1, 29 percent (9/31) of group 2, and in 7 percent (1/15) of group 3. No statistically significant difference between the three groups was observed for degree of inflammation, periradicular or interradicular abscess or inflammatory root resorption (chi-square p > 0.05). Dentin bridges were observed in 52 percent (16/31) of the teeth in group 1, 52 percent (16/31) of those of group 2, and in 73 percent (11/15) of those of group 3. No difference was found between the experimental and control groups for the presence of dentin bridge, (p > 0.05). Ferric sulfate produced pulp responses that compared favorably to those of diluted formocresol.

Treatment trends during a thirteen-year period in a student pediatric dentistry clinic.

This manuscript reports the treatment trends in a pediatric dentistry clinic from 1980 to 1992 and discusses their implication in clinical teaching. Analysis of the records of the senior year pediatric dentistry students indicated: no significant change with time in the patients/student ratio, the number of preformed crowns, pulpotomies, and pulpectomies by student or by patient; a significant decrease in the number of one-surface and > or = 2-surface restorations by student and by patient; a significant increase in the number of pit-and-fissure sealants and preventive resin restorations by student and by patient. During the thirteen-year period, the students performed an average of 7.3 one-surface; 12.9 > or = 2-surface restorations; 5.5 preformed crowns; 6.4 pit-and-fissure sealants; 2.4 pulpotomies. There was a significant increase with time in the number of students who performed pit-and-fissure sealants.

Internal coronal resorption of a permanent molar: a conservative approach for treatment.

A case of internal coronal resorption in a maxillary first permanent molar of a young adult is described. Conservative treatment was done, which included endodontic therapy followed by coronal restoration with bonded composites. The importance of early diagnosis and treatment of the resorptive defect is stressed.

The effect of internal bevel on marginal leakage at the approximal surface of Class 2 composite restorations.

The aim of this study was to assess the effect of intentionally leaving undermined enamel (internal bevel) along the cervical margins of class 2 composites on marginal leakage. Conventional MO and DO cavity preparations were prepared in 25 extracted permanent premolars. In each tooth the cervical margin was a butt-joint for the control group and an internal bevel for the experimental group. A transparent celluloid matrix was adapted and the teeth were restored with scotchbond Multi-Purpose and increments of Z100. A U-shaped increment was attached to the buccal and lingual walls and cervical floor of the box, leaving a gap for a middle increment. A third increment filled the occlusal part of the cavity. Following thermocycling the teeth were immersed in basic fuchsin for 24 hours, and 0.5 mm-wide sections were cut in a mesiodistal direction. Dye penetration was scored: 0 = no penetration; 1 = dye along enamel tooth interface; 2 = dye along the gingival floor; 3 = dye along pulpal wall; 4 = dye penetration into dentinal tubules. The experimental group showed 17 teeth (68%) with no dye penetration, compared to eight (32%) in the control group. Severe dye penetration (score 4) was found in only four teeth (16%) of the experimental group and 12 (48%) of the controls. The difference between the groups was statistically significant (Wilcoxon matched-pairs signed-rank test; P < 0.01). This study showed that an internal bevel at the cervical margins of class 2 composite restorations reduces marginal leakage when compared to a conventional butt-joint cavity preparation.

Clinical evaluation of Class II combined amalgam-composite restorations in primary molars after 6 to 30 months.

Composites are claimed to be inappropriate for Class II restoration due to polymerization shrinkage. The present study evaluated the clinical and radiographic appearance of Class II combined amalgam composite restorations in primary molars. Conventional cavities (groups A & B) were restored with 1mm thick amalgam at the cervical floor covered by a posterior composite (Estilux Posterior). In group A Amalgambond was placed between the layers: in group B conventional enamel bond was applied. Vertical increments of Estilux Posterior over enamel bond restored cavities of group C. A fluted carbide bur and Sof-lex discs finished all restorations. Criteria developed by Cvar & Ryge (1971) were used for clinical evaluation of 39 restorations (12, 16 and 11 of Groups A, B and C respectively). No complaints of pain or discomfort were reported during the 6-30 months (mean 15.3) follow-up period. All groups presented excellent surface appearance. Ninety-two percent of group A and 100 percent of groups B & C presented excellent marginal adaptation. Anatomic form was excellent in 92 percent, 8 percent and 100 percent of groups A, B and C respectively. The underlying amalgam was visible through the composite of groups A & B reducing the percentage of excellent ratings of color match to 33 percent and 38 percent respectively, with 9 percent in Group C. This difference was significant (P < 0.02). Secondary caries was observed in two teeth (group A & C). Radiographs presented radiolucent area at the amalgam-composite interface only in one restoration (group A) and one at the tooth-composite interface (group C). Bubbles were found in 6.6 percent of group A; 12.5 percent of group and 64 percent of group C (p < 0.01). This study detected differences between the groups only in color match and the presence of bubbles.

The preventive resin (composite resin/sealant) restoration: nine-year results.

This study was performed to examine the 9-year success of the composite resin/sealant restoration, which uses "sealing for prevention" of fissure caries rather than "cavity extension for prevention." Three hundred thirty-two Class I restorations were placed in the occlusal surfaces of 240 permanent molar teeth in 114 children aged 6 to 14. Cavity preparations were made in occlusal surfaces, and caries was removed with no attempt to create any additional retention or remove undermined enamel. Exposed dentin was covered with Dycal and the cavity was restored with Radiopaque Adaptic, which was then covered with Delton fissure sealant. Incipient lesions confined to the enamel were restored only with Delton. After 9 years, 79 restorations in 28 subjects were examined for sealant retention, marginal staining, and the presence of dental caries. Forty-three restorations (54%) had completely retained sealants, 20 (25%) had sustained partial loss, and 16 (20%) of the restorations had lost all sealant. Dental caries occurred in 19 (25%) of the restorations that had sealant loss. An additional 16 teeth had proximal caries unrelated to the occlusal restoration. These findings demonstrated that the composite resin/sealant (preventive resin) restoration produced excellent long-term results.