Direct composite veneers can be used to mask tooth discolorations and/or to correct unaesthetic tooth forms and/or positions. However, these type of restorations are often regarded as one of the most challenging in aesthetic dentistry presumably due to the extent of natural tooth structure that must be recreated. This paper discusses easy application techniques and tips for Ceram.X Duo™, a nano ceramic composite restorative material. Its natural shading system allows the restoration of tooth with both dentine and enamel shade and transforms it into a final direct veneer restoration that mimics a natural tooth.
The aim of the study was to determine the depth of cure of a new nanocomposite when exposed to different curing times and also when different shades were polymerized. The nanocomposite, Filtek Supreme (3M ESPE), was packed into 96 plastic cylindrical moulds measuring 4 mm in internal diameter and 8 mm in length and then polymerized using a conventional quartz-tungsten-halogen light curing unit. The first part of the study involved curing 16 samples each of A2 shade of the nanocomposite at exposure times of 20s, 40s, 60s and 120s. For the second part, a similar number of samples of the dentinal opacity shades of A2, B3 and A4 of the nanocomposite were polymerized at a constant exposure time of 40s. The depth of polymerization of the nanocomposite in each sample was measured using a digimatic indicator. Curing depths were found to increase significantly (P < 0.05) with longer exposure time (20s < 40s < 60s < 120s) and decrease significantly with darker shades (A2 > B3 > A4).
Decalcified permanent teeth were sectioned and stained with Van Gieson and Gomori trichome dyes. Sections dyed with the Van Gieson dye did not produce any zones in dentine but with the Gomori trichome dye, four different zones of dentine were produced. Zone 1 begins at the predentine-dentine junction while zone 4 ends at the enamel - dentine junction. In zone 1, the intertubular dentine was stained clearly while in zone 3 intense staining of the peritubular dentine was observed. The result of this study supports the previous findings reported by other workers that the formation of intertubular dentine takes place in zone 1 while peritubular dentine occurs in zone 3.
Phosphophoryn, a higWyphosphorylated protein, is the most abundant protein among the non-collagenous protein of dentine. The staining of phosphophoryn can be done by using the silver colloid staining. In this paper, the staining effect of the silver colloid stain on both non-sclerotic and sclerotic dentine was investigated. Eight teeth from donors aged 14, 17, 22, 34, 55, 57, 60 and 65 were used for this experiment. The younger teeth were used to demonstrate normal root dentine while the older age teeth were used to demonstrate sclerotic root dentine at the apical region of the root. There was no staining of the normal root dentine as compared to sclerotic dentine when the silver colloid staining was used.
The estimation of age of human foetal remains is of great medico-legal importance. When the remains are intact and fresh, various morphological features such as crown-heel length, weight, appearance of ossification centres particularly around the ankles and knees and other parameters could be used to make a reasonable estimation of the period of gestation. In cases of criminal abortion, infanticide and child murder the question of age of the foetus, viability, live birth and a separate existence become very important. In practice, often at the time of detection, the remains are decomposed or skeletonised. In such a situation the examination of developing teeth will provide a reliable answer pertaining to the foetal age, the possibility of a separate existence and even the period of survival after birth. The.age determination from dental examination is possible from approximately 10 weeks intrauterine up to old age. The presence of neonatal line (birth line) in both dentine and enamel indicates live birth and a separate existence. It is possible that the time period of survival can be estimated by measuring postnatal deposition of these hard tissues. An intact human foetus that has undergone mild to moderate putrefaction was studied. The study of the morphological features and the ossification centres suggested that its approximate age was around nine months intrauterine. It was not possible to decide whether it was a live birth and had a separate existence. The examination of the developing first deciduous molar of the mandible suggested the approximate age was around 30-32 weeks intrauterine. The importance of examination of developing teeth in foetal remains (including neonates), particularly associated with putrefaction or skeletonisation is emphasized.
The objective of this study was to investigate the effect of various luting cement systems on bond strength of fibre-reinforced posts to root canal dentine. 40 extracted single rooted sound premolar teeth were root filled, decoronated and randomly divided into four groups. Fibre posts, Aestheti- Plus™ (Bisco,Inc. Schaumburg, IL, USA) were cemented using four luting cements: Group A (control): Elite 100® Zinc phosphate (GC Corp, Japan), Group B: Calibra ™ Esthetic Resin Cement (Dentsply Caulk, USA), Group C: RelyX ARC Adhesive Resin (3M ESPE), Group D: RelyX Unicem Aplicap (3M ESPE). Each root was sliced into 2 discs representing the coronal and middle portions of the root canal giving rise to 20 specimens per group. Bond strength was determined using push-out tests and data was analyzed using SPSS version 14.0. The mean bond strength of Group A to Aestheti-Plus™ post was 7.71 MPa (±2.51) and Group B was 5.69 MPa (±3.23). Group C exhibited the lowest mean bond strength, 4.29 MPa (±3.53) while the highest bond strength was obtained from Group D, 7.98 MPa (±2.61). One way ANOVA showed significant interaction between all groups (p=.OOI). Post-hoc Bonferroni test reve;iled that bond strength of Group C was significantly lower compared to Group A (p=.008) and D (p=.004). In conclusion, the mean bond strength of Aestheti- Plus™ post to root canal dentine was highest when cemented with RelyX Unicem resin cement followed by Elite 100® zinc phosphate cement, Calibra and RelyX ARC resin cements. However, the bond strengths of Cali bra and RelyX Unicem resin cements were not significantly different from Elite 100® zinc phosphate cement.
The medicaments used in this study were buffered glutaraldehyde and formocresol. Schiff's reagent was used in the quantification of aldehyde released into the collecting medium. The results of this study clearly show that formocresol diffused throughout the dentine and cementum within fifteen minutes following a pulpotomy procedure, whereas no diffusion of buffered glutaraldehyde was observed.