Identification of Key Functional Motifs of Native Amelogenin Protein for Dental Enamel Remineralisation.

Dental caries or tooth decay is a preventable and multifactorial disease that affects billions of people globally and is a particular concern in younger populations. This decay arises from acid demineralisation of tooth enamel resulting in mineral loss from the subsurface. The remineralisation of early enamel carious lesions could prevent the cavitation of teeth. The enamel protein amelogenin constitutes 90% of the total enamel matrix protein in teeth and plays a key role in the biomineralisation of tooth enamel. The physiological importance of amelogenin has led to the investigation of the possible development of amelogenin-derived biomimetics against dental caries. We herein review the literature on amelogenin, its primary and secondary structure, comparison to related species, and its' in vivo processing to bioactive peptide fragments. The key structural motifs of amelogenin that enable enamel remineralisation are discussed. The presence of several motifs in the amelogenin structure (such as polyproline, N- and C-terminal domains and C-terminal orientation) were shown to play a critical role in the formation of particle shape during remineralization. Understanding the function/structure relationships of amelogenin can aid in the rational design of synthetic polypeptides for biomineralisation, halting enamel loss and leading to improved therapies for tooth decay.

Comparative evaluation of qualitative and quantitative remineralization potential of four different remineralizing agents in enamel using energy-dispersive X-ray: An in vitro study.

BACKGROUND: The principles of minimally invasive dentistry clearly tells us the need for clinically effective measures to remineralize the early enamel caries lesions. AIMS AND OBJECTIVES: The aim of this study was to evaluate the remineralisation potential of four different remineralisation agents used quantitatively by surface microhardness and qualitatively by energy dispersive X ray analysis. MATERIALS AND METHODS: Artificial enamel lesions were created on the buccal surfaces of 60 extracted mandibular second premolar. Specimens were randomly assigned to four groups (n=15) according to the remineralisation agents used: Group 1-Nano Hydroxyapatite, Group 2-Fluoride, Group 3-CPP ACP, Group 4-Chitosan 5mg. All products were applied according to the manufacturer's instructions and specimens were stored in daily renewed artificial saliva. Surface microhardness was assessed using Rockwell hardness test and change in mineral content was evaluated using Energy Dispersive X ray analysis. STATISTICAL ANALYSIS: One way analysis of Variance test and post-hoc Tukey test were conducted for multiple group comparison. RESULTS: There was remarkable remineralisation in Hydroxyapatite treated comparatively to the other three groups. CONCLUSION: All remineralising agents showed improved surface remineralisation. However complete remineralisation did not occur within 7 days. Nanohydroxyapatite showed the highest potential for remineralisation followed by CPP-ACP, Chitosan and Fluoride.

Evaluation of the remineralisation potential of bioactive glass, nanohydroxyapatite and casein phosphopeptide-amorphous calcium phosphate fluoride-based toothpastes on enamel erosion lesion -An Ex Vivo study.

BACKGROUND: Erosion, a dynamic process with periods of demineralisation and remineralisation, has become a common problem in modern societies, owing to changes in life style and dietary habits. Although fluorides have been included in toothpastes that claim to prevent demineralisation and aid remineralisation, their ability to remineralise is limited by low concentration of calcium and phosphate ions available in saliva. Hence, a new paste based on casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF), nanohydroxyapatite and bioactive glass (BAG) were introduced. AIM: To evaluate and compare the effects of BAG, nanohydroxyapatite and CPP-ACPF pastes on surface microhardness of demineralised enamel. MATERIALS AND METHODS: 48 enamel specimens were randomly divided into five groups: Group I positive control - intact specimens and Group II - demineralised specimens. The test groups, Group III, IV and V, comprised CPP-ACPF, nanohydroxyapatite and BAG, respectively. The test specimens were demineralised with 0.1% citric acid followed by remineralisation using either of the three prepared slurries. The specimens were subjected to pH cycling regime for 15 times. The remineralisation potential of the specimens was studied by evaluating the surface microhardness. One specimen from each group was analysed under SEM. Data was tabulated and analysis performed by one way ANOVA and post hoc Scheffe test. RESULTS: Statistically significant difference was found between the negative control and three test groups based on microhardness evaluation. Nanohydroxyapatite had the least remineralising potential as compared to CPP-ACPF and BAG. CONCLUSION: Comparatively, BAG and CCP-ACPF paste showed better remineralising potential.

Efficacy of pastes containing CPP-ACP and CPP-ACFP in patients with Sjögren's syndrome.

OBJECTIVES: The purpose of this study was to evaluate efficacy of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and casein phosphopeptide-amorphous calcium fluoride phosphate (CPP-ACFP) containing pastes among individuals with Sjögren's syndrome (SS). MATERIALS AND METHODS: Thirty patients were randomised into three groups: CPP-ACP, CPP-ACFP, and 0.05 % NaF to be used two times a day during a 28-day experimental period. Saliva was analysed for flow rate, pH, buffering capacity and mineral concentrations. Dental plaque was examined for pH. Following the formation of artificial carious lesion, participants wore enamel slabs for an in situ remineralisation study. Remineralisation potential was examined using scanning electron microscope (SEM) and energy dispersive spectroscopic (EDS) technique. SE microphotographs were subsequently analysed for area, diameter, perimeter, roundness and the number of enamel defects and percentage of tooth surface affected by defects. RESULTS: At the end of the experimental period, a slight increase of salivary pH could have been observed. No differences in mineral composition of saliva were noted. The use of CPP-ACP and CPP-ACFP contributed to a significant rise of plaque pH. Image analysis revealed excessive reduction of defects' dimensions in the three experimental groups, and a decrease of the number of enamel defects in the CPP-ACP and CPP-ACFP groups. The EDS analysis did not show differences in Ca/P, Ca/O and P/O ratios in any of the treatment groups. CONCLUSION: CPP-ACP and CPP-ACFP hold promise as remineralising agents for patients with SS. CLINICAL RELEVANCE: Pastes containing CPP-ACP/CPP-ACFP show enhanced remineralisation potential compared with NaF mouthrinse in patients with SS.

Measuring color change of tooth enamel by in vitro remineralization of white spot lesion / Medición del cambio de coloración del esmalte dental en la remineralización in vitro de la lesión incipiente de caries

Abstract: objective colour determination is based on calculating the colorimetricdistance (Delta E) within a colour space. So far, the most used colour space in dentistry is CIE L*a*b (Comission Internationale de l´Éclairage). CIE L*C*h* has been recently developed, showing a better correlation with the perception of the human eye. Objective: To determine the ability of an in vitro remineralisation substance to blend the colour of white spot lesions (WSL) with sound enamel, determining Delta E by using the CIE L*C*h* colour space. Methods: In vitro WSL was generated by immersing 10 samples obtained from human third molars in a demineralization solution for 72h. Amorphous calcium phosphate stabilized by casein phosphopeptide (CPP-ACP) was then applied for 60 days while maintaining the samples in artificial saliva at 37ºC. To evaluate the colour of enamel, images were taken from the samples placed in specifically designed silicone moulds after generating the WSL (pre-stage) and after remineralisation by scanning, applying the colorimetric distance equation (Delta E*CMC) according to the Colour Measurement Committee. Results: Treatment with CPP-ACP caused a significant Delta E decrease with respect to the pre-stage (p smaller than 0.001), while the analysis of parameters that make up the colour showed a reduction in the difference of hue (Delta H) (p smaller than 0.001) and brightness (Delta L) (p smaller than 0.01) after applying CPP-ACP. Discussion: CPP-ACP penetrated to the depth of the white spot lesion, making its appearance similar to that of the sound enamel, probably because of the formation of different mineral phases than that of the original structure, although pores were not completely filled.

Resumen: la determinación objetiva del color se basa en el cálculo de la distancia colorimétrica (Delta E) dentro de un espacio cromático. Hasta el momento el más usado en odontología ha sido CIE L*a*b (Comission Internationale de l´Éclairage). Recientemente se ha desarrollado CIE L*C*h*, que tiene mayor correspondencia con la percepción del ojo humano. Objetivo: evaluar la capacidad de una sustancia remineralizante de mimetizar el color de la mancha blanca (MB) in vitro con el esmalte sano, determinando Delta E mediante el espacio cromático CIE L*C*h*. Método: se generó la MB in vitro sumergiendo 10 muestras obtenidas de terceros molares humanos en solución desmineralizante durante 72 h., luego se aplicó pasta con fosfato de calcio amorfo estabilizado por fosfopéptidos de caseína (CPP-ACP) durante 60 días manteniendo las muestras en saliva artificial a 37ºC. Para evaluar el color, se obtuvieron imágenes de las muestras ubicadas en moldes de silicona confeccionadas ad hoc luego de generar la MB (etapa pre) y del protocolo remineralizante (etapa post) mediante escáner y se aplicó la ecuación de Distancia colorimétrica según Color Measurement Committee. (Delta E*CMC). Resultados: el tratamiento con CPP-ACP provocó una disminución significativa de Delta E respecto de la etapa pre (p menor que 0,001) mientras que el análisis de los parámetros que componen el color mostró disminución en la diferencia del tono (Delta H) (p menor que 0,001) y la luminosidad ( Delta L ) (p menor que 0,01) luego de aplicar CPP-ACP. Discusión: CPP-ACP penetró a la profundidad de la lesión, acercando la apariencia de la MB a la del esmalte sano, probablemente por la formación de fases minerales distintas a las de la estructura original aun cuando lo poros no hayan sido completamente rellenados.

Remineralization of early enamel lesions using casein phosphopeptide amorphous calcium Phosphate: an ex-vivo study.

OBJECTIVE: This study aimed at qualitatively evaluating the remineralization potential of casein phosphopeptide amorphous calcium phosphate on artificial early enamel lesions in an ex-vivo scenario by observing the treated tooth surface using a scanning electron microscope (SEM). MATERIALS AND METHODS: This randomized study was conducted on 10 subjects undergoing orthodontic treatment with premolar extraction as part of their treatment. Artificial white lesions were created with the application of 37% phosphoric acid for 20 mins. Teeth were then divided into two groups: one experimental and the other control. Customised orthodontic band with a window was luted with intermediate restorative material in the experimental group whereas in the control group, band without a window was luted. The casein phosphopeptide amorphous calcium phosphate (GC TOOTH MOUSSE) paste was then applied on the window region of the experimental group for 3 mins thrice daily after meals for 14 days, whereas no paste was applied in the control group. After 14 days, teeth were extracted and viewed under an SEM. RESULTS: The study groups showed remineralization of the lesions as compared with the control group in most of the samples. CONCLUSION: Casein phophopeptide could significantly remineralize the artificial enamel lesions in vivo.