Polymerization shrinkage and depth of cure of packable composites.

OBJECTIVE: This investigation evaluated polymerization shrinkage and depth of cure of five packable composites. METHOD AND MATERIALS: Five materials were used for the investigation: Alert, Surefil, Solitaire, P60, and Prodigy Condensable. Groups of 10 specimens of each material were made measuring either 2 or 5 mm in thickness, mounted in a testing jig, and polymerized using a dental curing light. Linear shrinkage was recorded and converted to a volumetric value. To evaluate depth of cure, ten specimens of each material were fabricated in both 2- and 5-mm thicknesses, and a Knoop hardness number was recorded on the top and bottom surfaces 5 minutes after light curing. A one-way analysis of variance statistical test was used to determine if there was a significant difference among materials. A Tukey multiple comparison test was then used to determine where significant differences existed. RESULTS: The volumetric shrinkage for the 2-mm-thick specimens from highest shrinkage to lowest were: Solitaire (3.3%), Prodigy Condensable (1.8%), Surefil (1.4%), P60 (1.2%), and Alert (0.2%). The 5-mm-thick specimens were ranked as follows: Solitaire (2.1%), Prodigy Condensable (1.0%), P60 (0.9%), Surefil (0.8%), and Alert (0.3%). Hardness for the bottom surface of the 2-mm-thick specimens showed that P60 (48.5) and Alert (42.6) had the highest values. Solitaire (11.2) had a significantly lower value. Hardness for the bottom surface at 5-mm thickness showed Alert (16.5) and P60 (16.3) with higher values than Surefil (8.9). CONCLUSION: Solitaire had the most shrinkage and Alert the least at both 2- and 5-mm depths. Depth of cure was severely compromised for all materials at 5 mm.     

Oral health status of 5 years and 12 years school going children in Chennai city--an epidemiological study

India, a developing country, faces many challenges in rendering oral health needs. The majority of Indian population resides in rural areas of which more than 40% constitute children. The purpose of this study was to assess the oral health status of 5 years and 12 years school going children in Chennai city. The study population consisted of 1200 school children of both the sexes (600 private and 600 corporation school children) in 30 schools, which had been selected randomly. The survey is based on WHO, 1999 Oral Health Assessment, which has been modified by including gingival assessment, enamel opacities/ hypoplasia for 5 years. Evaluation of the oral health status of these children revealed, dental caries is the most prevalent disease affecting permanent teeth, more than primary teeth and more in corporation than in private schools, thereby, correlating with the socioeconomic status. It may be concluded that the greatest need of dental health education is at an early age including proper instruction of oral hygiene practices and school based preventive programs, which would help in improving preventive dental behaviour and attitude which is beneficial for life time.     

Chemically distinct stages in developing human fetal enamel

Chemical analyses and the appearance of developing enamel from maxillary first incisors of human fetuses aged 5–9 months distinguished two stages during this period of development. The first corresponded to the production of forming enamel, which was soft, translucent and partially mineralized, and the second to the maturation or secondary mineralization of enamel. The final stage in enamel development, i.e. the mature, hard enamel is, however, generally absent in the tooth of the 9 month old fetus. The concentrations of P and Ca of the forming enamel in the tooth axis did not change significantly, varying between 9–12 and 21–26 per cent by weight, respectively. However, the P and Ca concentrations rose steeply across the boundary between the forming and the maturing enamel to reach a maximum value of 17 and 35 per cent, respectively, in the second stage.     

Subglossopalatal synechia in association with cardiac and digital anomalies.

A 1-day-old boy in respiratory distress had a midline soft tissue band between the floor of the mouth and the posterior edge of the hard palate. There was also a soft palatal cleft, cardiac anomalies, and a hypoplastic right fifth finger and toe. Although his airway initially improved following urgent excision of the subglossopalatal band, he continued to have episodic desaturations. A tongue-lip adhesion opened his airway, and he subsequently underwent resection of juxtaductal aortic coarctation and ligation of patent ductus arteriosus and left superior vena cava. Congenital oral synechiae are uncommon. Affected infants often require prompt intervention secondary to respiratory distress and feeding difficulty. Review of the literature indicates that midline subglossopalatal synechia with cardiac and digital anomalies may be in the oromandibular-limb hypogenesis spectrum.     

The effect of multiple uses of disposable diamond burs on restoration leakage

BACKGROUND: The authors tested the clinical longevity of disposable diamond burs. They cut a series of five preparations and assessed the leakage after restoring the tooth. METHODS: The authors prepared 10 teeth for Class V restorations, and used a new disposable diamond bur for each tooth. The burs were used to cut preparations in extra teeth before being used to prepare a second series of 10 teeth (third use). The authors then cut preparations in extra teeth before preparing a third set of 10 teeth (fifth use). They removed existing restorations in a second group of 30 teeth and extended the preparations using the same regimen of one, three and five bur uses. All preparations were etched and conditioned, and the teeth were restored with resin-based composite. Using a 20-volt direct-current power source and a stainless-steel counter electrode, the authors measured the leakage electrochemically in 1.0 percent sodium chloride for 30 days. RESULTS: Freshly prepared and restored teeth leaked less than reprepared teeth. Leakage was similar for the first and third uses of the bur, but was far greater for the fifth use (P < .01). The previously restored teeth that were cut with the first- and third-use burs behaved the same, but the third-use bur caused more leakage than the fifth-use bur (P < .01). CONCLUSIONS: Reuse of disposable burs can affect leakage behavior. With new preparations, use of a disposable bur to cut more than three preparations increased leakage. For teeth that were reprepared and restored, greater leakage occurred than it did with new preparations, although repeated use of a bur may reduce leakage. CLINICAL IMPLICATIONS: Disposable diamond burs may cut preparations in up to three teeth before adversely affecting leakage behavior. Restoration removal and repreparation of teeth results in greater leakage than that with freshly prepared teeth.     

A compound composite odontoma associated with unerupted permanent incisor--a case report

Odontomas are the most common type of odontogenic tumors and generally they are asymptomatic. Frequently it may interfere with the eruption of the teeth. This is a case report of a compound composite odontoma in a 9 year old girl, which results in failure of eruption of the permanent upper right central incisor while the contralateral tooth had erupted. A calcified mass was seen in the radiograph and was provisionally diagnosed as odontoma following which the odontoma was enucleated. Routine follow up was done for more than a year and no recurrence was seen. This case report indicates that early diagnosis and management ensures better prognosis.