Monday, September 26, 2011

Cell Transplantation study shows bone growth from implanted tooth and dental pulp stem cells


Researchers in Japan have completed a study showing that stem cells derived from deciduous canine teeth and dental pulp can be grafted and produce bone regeneration between parents and offspring. Their results are published in the current issue of Cell Transplantation (20:7), now freely available on-line.

"Bone defects can occur for a number of reasons, and autogenous bone grafting - using the patient's own bone - has been a standard approach to treatment," said study corresponding author Dr. Yoichi Yamada of the Center for Genetic and Regenerative Medicine at the Nagoya University School of Medicine. "However, considering severe invasiveness in self-donor bone sites, and the limited supply of autogenous bone, alternative donor sources are needed."

The researchers note that previous studies have shown that oral and maxillofacial dental tissues contain a variety of stem cells, such as dental pulp stem cells and stem cells from deciduous teeth. Stem cells, they note, can be easily extracted from deciduous teeth, which are routinely lost in childhood and generally discarded.

"Stem cells from human exfoliated deciduous teeth were identified as a novel population of stem cells, capable of differentiating into various cell types, such as osteoblasts, odontoblasts, adipocytes and neural cells," explained Dr. Yamada.

Their study extracted deciduous teeth from canine puppies and grafted them onto parent canine mandibles as an allograft. After four weeks, bone defects were prepared on both sides of the host mandible. The newly formed bone was evaluated at two, four and eight weeks. When compared to controls, the study group demonstrated well-formed mature bone and neovascularization.

The researchers reported that stem cells derived from dental pulp "display increased immunosuppressive activity when compared to bone marrow mesenchymal cells" and will likely have "immunosuppressive activity with potential clinical applications in allogenic in vivo stem cell transplantation, particularly for calcified tissue reconstruction."

Their pre-clinical study could pave the way for stem cell therapy in othropedics and oral maxillofacial reconstruction, concluded Dr. Yamata.

"This study highlights the promise of obtaining stem cells from unusual sources, such as teeth, and their potential benefit in familial treatments for bone reconstruction" said Dr. Julio Voltarelli, professor of Clinical Medicine and Clinical Immunology at the University of Sao Pãulo, Brazil, and section editor for Cell Transplantation. "Due to their potential to also become other cell types such as neural cells, it will be interesting to see what future studies reveal about the possible uses of these cells."

Tuesday, September 13, 2011

Sugar-free polyol gum, lozenges, hard candy; Nonfluoride varnishes help prevent cavities

Recommended in conjunction with fluoride for patients at high-risk for developing cavities

A multi-disciplinary expert panel, convened by the American Dental Association (ADA) Council on Scientific Affairs, issued a report this month containing clinical recommendations that sugar-free chewing gum, lozenges and hard candy including xylitol or polyol combinations, and a prescription varnish with chlorhexidine and thymol could be beneficial in preventing cavities when used as adjuncts to a comprehensive cavity prevention program which includes the use of fluoride-containing products.

The panel noted in its report that these nonfluoride options could provide an extra benefit to prevent cavities in patients at high risk for developing cavities when used in addition to products such as toothpaste, dental sealants and varnishes that contain fluoride as well as community water fluoridation and good eating habits.

The executive summary of the report entitled, "Nonfluoride Caries Preventive Agents," is published in the September issue of The Journal for the American Dental Association and is available on the EBD website. The clinical recommendations from the expert panel were reviewed and approved by the ADA's Council on Scientific Affairs.

The ADA recommends that clinicians determine a patient's risk for developing cavities by conducting a caries risk assessment, The Caries Form (Patients Ages 0-6 Years) and the Caries Form (Patients Over 6 Years) which includes completing a caries risk assessment form that can be used as a communications tool with their patients.

Nonfluoride agents

In addition to a comprehensive cavity-prevention program which includes the use of fluoride, the scientific panel recommended that clinicians consider applying a mixture of cholrhexidine-thymol varnish to the teeth of high-risk adults and the elderly every three months to reduce cavities developing in the root of the tooth.

The panel encouraged clinicians to consider advising parents and caregivers of healthy children older than 5 years who are at higher risk for cavities to chew sugar-free polyol gum after meals for 10 to 20 minutes to prevent cavities.

A polyol is a low-calorie sweetener such as xylitol, sorbitol or mannitol, which is not broken down by the bacteria in the mouth and therefore does not contribute to tooth decay. The panel also recommended that sucking xylitol-containing sugar-free lozenges or hard candy after meals may reduce cavities in children.

The panel's recommendations are based on a review of evidence from 71 published articles that described 50 randomized controlled trials and 15 nonrandomized studies to assess the effectiveness of various nonfluoride agents in preventing cavities.

ADA expert panels, Evidence-Based Dentistry

The clinical recommendations, developed by expert multidisciplinary panels convened by the ADA Council on Scientific Affairs, assessed available scientific evidence and developed practice-oriented recommendations through a comprehensive evidence-based process.

Evidence-based clinical recommendations are intended to provide dentists and other health professionals with a review of the latest scientific evidence on particular topics and are not considered a standard of care. Rather, health care professionals can consider clinical recommendations, patient preference and their own clinical judgment when diagnosing and treating patients.

Thursday, September 1, 2011

Caries-Preventive Agents: Nonfluoride Caries-Preventive Agents: Executive Summary of Evidence-Based Clinical Recommendations


In this report, the authors present evidence-based clinical recommendations regarding the use of nonfluoride caries preventive agents. The recommendations were developed by an
expert panel convened by the American Dental Association (ADA)
Council on Scientific Affairs. The panel addressed several questions
regarding the efficacy of nonfluoride agents in reducing the incidence
of caries and arresting or reversing the progression of caries.

Types of Studies Reviewed

A panel of experts convened by
the ADA Council on Scientific Affairs, in collaboration with ADA
Division of Science staff, conducted a MEDLINE search to identify
all randomized and nonrandomized clinical studies regarding the
use of nonfluoride caries-preventive agents.


The panel reviewed evidence from 50 randomized controlled
trials and 15 nonrandomized studies to assess the efficacy of
various nonfluoride caries-preventive agents.

Clinical Implications

The panel concluded that certain nonfluoride
agents may provide some benefit as adjunctive therapies in
children and adults at higher risk of developing caries. These recommendations
are presented as a resource for dentists to consider
in the clinical decision-making process.


Sealants and dental caries

The authors conducted a study to survey the perspectives of dentists
regarding the 2010 American Dental Association (ADA) recommendation to seal noncavitated carious lesions (NCCLs) in children and young adults.


The authors mailed a questionnaire
to a randomly selected sample of 2,400 general dentists
(GDs) and pediatric dentists (PDs) in the United States.
The sample was chosen by the ADA’s Survey Center. The
questionnaire included two photographs of NCCLs (permanent
first molar and premolar) in a 12-year-old child. Respondents
were provided with radiographic findings and asked to
choose from several management options.


In the absence of radiographic evidence of caries,
37.4 percent and 42.3 percent of GDs and PDs, respectively,
indicated that they would seal the NCCL in the molar. For
the premolar, a significantly lower percentage of GDs than of
PDs indicated that they would seal the NCCL. With radiographic
evidence of caries in dentin, less than 4 percent of all
dentists surveyed indicated that they would seal the NCCLs,
and more than 90 percent indicated that they would remove
the caries and place restorations. Less than 40 percent of
dentists indicated that they sealed NCCLs in their practice.
Conclusions. The U.S. dentists surveyed have not adopted
evidence-based clinical recommendations regarding the
sealing of NCCLs.

Practice Implications

New educational and dissemination
programs should be developed regarding these evidence-based
caries management approaches.