Brief Article
Copyright ©2013 Baishideng. All rights reserved.
World J Stomatol. Feb 20, 2013; 2(1): 12-17
Published online Feb 20, 2013. doi: 10.5321/wjs.v2.i1.12
Effects of low intensity laser irradiation phototherapy on dental pulp constructs
Amr M Elnaghy, Peter E Murray, Paul Bradley, Melissa Marchesan, Kenneth N Namerow, Amany E Badr, Youssry M El-Hawary, Farid A Badria
Amr M Elnaghy, Conservative Dentistry and Endodontics Department, Faculty of Dentistry, Mansoura University, Mansoura 35516, Egypt
Peter E Murray, Melissa Marchesan, Kenneth N Namerow, Department of Endodontics, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, FL 33328-2018, United States
Paul Bradley, Department of Orofacial Pain, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, FL 33328-2018, United States
Amany E Badr, Youssry M El-Hawary, Department of Oral Biology, Faculty of Dentistry, Mansoura University, Mansoura 35516, Egypt
Farid A Badria, Department of Pharmacognosy, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
Author contributions: All authors contributed equally to this work.
Correspondence to: Dr. Peter E Murray, PhD, Professor, Department of Endodontics, College of Dental Medicine, Nova Southeastern University, 3200 South University Drive, Fort Lauderdale, FL 33328-2018, United States. petemurr@nova.edu
Telephone: +1-954-2621743 Fax: +1-954-2621743
Received: August 25, 2012
Revised: January 4, 2013
Accepted: January 17, 2013
Published online: February 20, 2013
Processing time: 192 Days and 12.9 Hours
Abstract

AIM: To investigate low intensity laser irradiation phototherapy (LILIP) on the proliferation, mineralization and degradation of dental pulp constructs.

METHODS: Stem cells from human exfoliated deciduous teeth (SHED) were grown to confluence and seeded on collagen scaffolds to create dental pulp constructs. LILIP was delivered to the dental pulp constructs using an 830 nm GaAIAs laser at an output power of 20 mW. The LILIP energy density was 0.4, 0.8, 1.2, and 2.4 J/cm2. After 8 d, the cell proliferation and degradation within the dental pulp constructs were measured using histologic criteria. After 28 d, the effect of LILIP on SHED mineralization was assessed by von Kossa staining.

RESULTS: SHED proliferation within the dental pulp constructs varied after exposure to the 0.4, 0.8, 1.2, and 2.4 J/cm2 LILIP energy densities (P < 0.05). The maximum proliferation of SHED in nutrient deficient media was 218% after exposure to a 1.2 J/cm2 LILIP energy density. SHED grown in nutrient deficient media after exposure to a 0.4, 0.8, and 1.2 J/cm2 LILIP energy density, proliferated by 167-218% compared to the untreated (non-LILIP) control group (P < 0.05). SHED exposed to a 0.4, 0.8, and 1.2 J/cm2 LILIP energy density, and grown in optimal nutritional conditions and proliferated by 147%-164% compared to the untreated (non-LILIP) control group (P < 0.05). The exposure of SHED to the highest LILIP energy density (2.4 J/cm2) caused a reduction of the cell proliferation of up to 73% of the untreated (non-LILIP) control (P < 0.05). The amount of mineral produced by SHED increased over time up to 28 d (P < 0.05). The 0.8 and 1.2 J/cm2 LILIP energy densities were the most effective at stimulating the increased the mineralization of the SHED from 150%-700% compared to untreated (non-LILIP) control over 28 d (P < 0.05). The degradation of dental pulp constructs was affected by LILIP (P < 0.05). The dental pulp constructs grown in optimal nutritional conditions exposed to a 0.8 J/cm2 or 1.2 J/cm2 LILIP energy density had 13% to 16% more degradation than the untreated (non-LILIP) control groups (P < 0.05). The other LILIP energy densities caused a 1% degradation of dental pulp constructs in optimal nutritional conditions (P > 0.05).

CONCLUSION: LILIP can enhance or reduce SHED proliferation, degradation and mineralization within dental pulp constructs. LILIP could promote the healing and regeneration of dental tissues.

Keywords: Dental pulp cells; Proliferation; Low intensity laser; Low intensity laser irradiation phototherapy; Stem cells from human exfoliated deciduous teeth