In vivo remineralization of artificial enamel carious lesions using a mineral-enriched mouthrinse and a fluoride dentifrice: a polarized light microscopic comparative evaluation.

BACKGROUND: Remineralization process is accelerated by the presence of fluoride ions in the oral environment, but this mechanism of caries reversal will be further enhanced if the concentration of calcium, phosphate and fluoride ions is supersaturated with respect to that of oral fluids. AIM: This in vivo study was carried out to evaluate and compare the remineralizing efficacy of a urea-based mineral-enriched mouthrinse and a fluoridated dentifrice using an in vivo intraoral appliance model and polarized light microscopic evaluation technique. MATERIALS AND METHODS: The specimens were prepared from sound teeth and artificial caries was produced using an artificial caries medium in vitro and enamel specimens were inserted in removable orthodontic appliances that were to be worn by 14 children of 10-15 years of age. They were divided into three groups - nonfluoridated dentifrice, fluoridated dentifrice and mineral-enriched mouthrinse groups. After the 6-month experimental period, during which the enamel specimens inserted in the intraoral appliance were subjected to one of the agents (either fluoride, nonfluoride dentifrice or mouthrinse) in vivo, the specimens were retrieved from the patients and were evaluated using the polarized light microscopic technique. OBSERVATIONS AND RESULTS: On analysis, mineral gain occurred in all groups, viz. nonfluoride dentifrice group, fluoride dentifrice and mineral-enriched mouthrinse group. However, it was found to be complete in the mouthrinse group, i.e. both at the surface and at the subsurface (67%), while in the fluoridated dentifrice group, 43% of the samples showed mineral gain in both zones. In the nonfluoridated dentifrice group also, remineralization occurred but was limited either to the surface or the subsurface zone. CONCLUSIONS: Urea-based mineral-enriched mouthrinse was shown to be more efficacious in the process of remineralization of artificial carious lesions.

Effectiveness of pectoralis major myocutaneous flap in the surgical management of oral cancer: A retrospective study.

INTRODUCTION: Over 80,000 oral cancer cases get diagnosed each year in India, majority undergoing extensive resections owing to their late presentation. Pectoralis major myocutaneous (PMMC) flap is a pedicled axial pattern flap which is based on thoracoacromical artery. It is readily available as a viable alternative to free flap reconstruction, especially for the economically poor and malnourished patients. Its proximity to head and neck structures gives added advantage to reconstruct complex and large volume oral and maxillofacial defects. It provides a relatively good possibility of functional and aesthetic restoration providing both mucosal lining and skin cover. MATERIALS AND METHODS: This was a prospective observational study of 29 PMMC flap reconstructions, conducted between 2013-2016. The reconstruction outcomes assessed in this study were divided into two categories namely "success" and "failure" based on certain functional parameters observed during follow-up of 1 year. The complications were broadly classified as major/minor and flap related/non-flap related. We assessed the feasibility of using a PMMC flap for reconstructing various subsites of oral cavity cancer. Further, the association of patient variables with complication rates and outcome of reconstruction were analysed. RESULTS: Out of 29 patients overall complications were noted in 15 (51.7%) cases with a female preponderance. Flap-related complications were noted in 9 whereas non-flap-related complications were seen in 6 patients. Major and minor complications were noted in 2 (both flap related) and 13 cases respectively. Complete full thickness flap necrosis was not encountered in any patient. Patients with flap skin paddle size ≤ 36 cm2 (n = 12) had significantly increased overall complication rates. Despite complications a high success rate (93.1%, n = 27) was achieved with this mode of reconstruction. CONCLUSION: The PMMC flap reconstruction is a versatile, reliable and an affordable single staged procedure with a high success rate in terms of achieving treatment goals. Although it has moderately high complication rates, but PMMC flap proved to be a workhorse in locally advanced cases of head and neck cancer at the end of 1 year follow-up.

Fibrinogen and fibrin protect fibroblast growth factor-2 from proteolytic degradation.

We have recently reported that fibrinogen and fibrin bind to fibroblast growth factor-2 (FGF-2) and potentiate its ability to stimulate proliferation of endothelial cells. In the present report, we have investigated the potential of fibrinogen and fibrin to protect FGF-2 from proteolytic degradation. FGF-2 was incubated with trypsin or chymotrypsin in the presence or absence of fibrinogen or fibrin and proteolysis of FGF-2 was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. In the absence of fibrinogen there was progressive tryptic degradation of FGF-2, but in the presence of fibrinogen, FGF-2 was completely protected from trypsin with no evidence of degradation. The degree of protection was maximum at a molar ratio of FGF-2 to fibrinogen 1:2. Fibrinogen afforded similar protection from degradation by chymotrypsin. Polymerized fibrin provided partial protection of FGF-2 from tryptic degradation, with intact FGF-2 present for up to 360 min. Fibrin provided nearly complete protection from chymotrypsin. These observations indicate that binding of FGF-2 to fibrinogen or fibrin provides protection from proteolytic degradation, and this may modulate its cell proliferative activity.

Remineralizing efficacy of a mineral enriched mouth rinse and fluoridated dentifrice on artificial carious lesions: an in vivo scanning electron microscopic study.

This comparative investigation was carried out to evaluate the remineralization potential on early artificial carious lesions under Scanning Electron Microscope (SEM) of a Mineral enriched mouthrinse and a fluoridated dentifrice using an in-vivo intra-oral removable appliance model. This findings revealed that the remineralization was found to have occurred in almost all the samples (in children) using non-fluoridated, fluoridated dentifrices as well as those using mineral enriched mouthrinse. However the qualitative analysis of the remineralization revealed that in case of non-fluoridated dentifrice group, the prismatic holes showed deposition of granular, variable sized particles with uneven distribution, while in fluoridated dentifrice group, deposits were found to have partially but more densely filled up the prism cores. In case of mineral enriched mouthrinse group these deposits were found to be in the form of amorphous globular precipitate.

A Cretaceous hoofed mammal from India.

The sedimentary record documenting the northward drift of India (Late Cretaceous to late Early Eocene) has recently provided important clues to the evolution, radiation, and dispersal of mammals. Here, we report a definitive Late Cretaceous (Maastrichtian) archaic ungulate (Kharmerungulatum vanvaleni genus et species nova) from the Deccan volcano-sedimentary sequences exposed near Kisalpuri village in Central India. This find has important implications for the origin and diversification of early ungulates and raises three possible paleobiogeographic scenarios: (i) Archaic ungulates may have been cosmopolitan in distribution. (ii) Kharmerungulatum might be an immigrant from Western Asia. (iii) Archaic ungulates may have originated in India.

Evolutionary aspects of reptilian and mammalian enamel structure.

The evolution of enamel structure is dealt with here on the basis of fossil reptiles and mammals ranging from the Triassic to the present. The evidence suggests that prismatic enamel had developed in some therapsid reptiles and the mammal, Eozostrodon about 180 million years ago. For the next 100 million years, mammalian evolutionary history is sparingly documented and this is reflected in the poor record of enamel evolution during this period. The few Jurassic reptiles and mammals studied suggest a preprismatic structure. In the Late Cretaceous (80 to 65 million years ago) when the fossil record improves, mammalian enamel investigated from North American localities, are found to be prismatic; allotherian (multituberculate) and metatherian (marsupial) enamels are usually tubular, while eutherian (placental) ones are not. Prism structure in Tertiary mammals in general, conforms to that of their present day descendants, but there are discernible exceptions. The record of evolutionary change in Tertiary mammals is obscured by functional modifications related to biomechanical stresses. Enamel structure may be secondarily modified; similar in phylogenetically unrelated groups (eg., pauciserial enamel of early rodents) or dissimilar at the intra-familial level (eg., rodent families Ctenodactylidae and Ischryomyicae). Prismatic enamel is recorded from the tooth of a hatchling of the gavial, Gavialis gangeticus.

Indraloris and Sivaladapis: Miocene adapid primates from the Siwaliks of India and Pakistan.

THE primate family Adapidae underwent a major radiation during the Eocene in Europe(1,2) and North America(3,4). Asian and African Eocene mammalian faunas are still poorly known, but there is sufficient evidence to indicate at least a modest radiation of Eocene adapids in Asia(5,6) and probably also in Africa(2). Apart from possible lemuriform and anthropoid primate derivatives, the family Adapidae was thought to have become extinct at the end of the Eocene (middle Tongrian, approximately 37 Myr (refs 2, 7, 8)). We present here new evidence which indicates that at least two genera of adapid primates, Indraloris and Sivaladapis (gen. nov.), survived into the late Miocene of India and Pakistan. These genera are little advanced over Eocene Adapidae in terms of dental adaptations and are apparently south Asian relicts of a much earlier radiation.