Platelet-rich plasma (PRP) therapy offers potential for nerve regeneration, particularly peripheral nerve recovery around dental implants. Regeneration of nerve fibers and restoration of sensory feedback can present problems following dental implant placement. Owing to its safety and applicability, PRP therapy has shown promise in treating musculoskeletal injuries. Reinhilde Jacobs (University of Leuven, Belgium), Haiyang Yu (Sichuan University, China) and and coworkers reviewed basic research studies and preliminary clinical trials on the biological efficacy of PRP in peripheral nerve regeneration. The authors concluded that various growth factors released by PRP may indeed modify and promote sensory feedback around a dental implant. However, further research is necessary before using PRP with dental implants can be advocated as safe, effective treatment. Among the authors' recommendations for future studies are optimizing the clinical efficacy of growth factors within PRP.

A survey of over 8 000 residents from Sichuan in China found evidence of poor oral health, especially dental caries and periodontal disease. The study, led by Tao Hu and Xuedong Zhou of Sichuan University, looked at teeth, gums and oral mucosa in three age groups: 3–5 years, 12 years, and 65–74 years. The examinations were performed using World Health Organization guidelines designed to promote international comparison. Despite significant improvements in recent years, oral disease in multiple forms was still highly prevalent in all age ranges, with rural areas suffering from poor disease prevention and treatment. The elderly had a particularly high prevalence of disease. The results of the survey provide strong evidence that improvement of oral health requires prioritization by local authorities.

Estrogen and interleukin-1(IL-1), a key regulator of immune responses, work together to confine dental infections to the local oral tissue. Left untreated, dental infection can spread to the head and neck causing further disease or death. Hesham Youssef and Philip Stashenko of the Forsyth Institute, Cambridge, USA, inhibited the action of IL-1 in mice before inducing infection in the dental pulp. They found that blocking IL-1 prevented the localization of infection in male mice but not in female mice. Subsequent blocking of estrogen in female mice also allowed infection to spread. The team found that estrogen increased the production of IL-1, which overcame the blockade and contributed to an effective immune response. This study highlights the importance of sex-specific responses to infection and offers a new avenue of exploration toprevent potentially lethal disease.

A detailed morphological study of the root canal system of upper second molar teeth could lead to better root canal treatment. Thomas Gerhard Wolf from the Johannes Gutenberg University Medical Center in Mainz, Germany, and colleagues scanned 123 extracted maxillary second molars using a three-dimensional X-ray imaging technique called micro-computed tomography. They evaluated the configuration of the teeth’s root canals using a four-digit classification system that divides each root into thirds with a fourth digit that describes the number of openings through which nerves and blood vessels pass. The researchers found little variation in two of the three roots, but the mesiobuccal root had 15 different configurations, more than had been observed previously with standard analytical techniques. The findings demonstrate the usefulness of the new imaging method and lay the groundwork for more precise root canal treatment.

Low-power laser irradiation (LPLI) could treat a debilitating pre-malignant, fibrotic condition of the mouth. Most cases of oral submucous fibrosis (OSF) are in South Asia and are associated with areca nut chewing. The compound arecoline in the nut is thought to be involved in its development. Yan-Hsiung Wang, Huey-Er Lee and colleagues of Taiwan’s Kaohsiung Medical University tested the effects of LPLI on fibroblasts, cells producing connective tissue, from the human gum, which they stimulated with arecoline. Applying LPLI can activate a key cell-regulating enzyme, adenylyl cyclase, reduced the expression of fibrosis-related genes. LPLI’s effect was blocked when the cells were pretreated with an adenylyl cyclase inhibitor. LPLI may inhibit the effects of arecoline via adenylyl cyclase and could be used as an antifibrotic therapy in the future.

A type of collagen found surrounding cells in jaw cartilage may help protect against inflammation associated with osteoarthritis. Cells called chondrocytes, which are responsible for maintaining healthy joint cartilage, are surrounded by a thin matrix layer known as the pericellular matrix (PCM). While interactions between chondrocytes and PCM molecules have been analyzed in knee joints, little is known about PCM molecules in the temporomandibular joint, where the upper jaw links to the skull. Wei Seong Toh at the National University of Singapore and co-workers investigated three PCM molecules (collagen VI, collagen IV and laminin) in rat jaws, and discovered that collagen VI is the most widely distributed across jaw cartilage. Pre-treating chondrocytes with collagen VI reduced nitric oxide levels and limited potentially damaging expression of some genes, thereby protecting the cells from inflammation. The discovery could inform osteoarthritis treatments.

A team of researchers has demonstrated a potential new method of designing treatments for dental caries via computer modeling. Jin-Ku Bao and collaborators from Sichuan University, China, used computer-aided drug design techniques to search libraries of compounds for inhibitors of Streptococcus mutans sortase A. This enzyme allows the bacteria to adhere to teeth and facilitate decay. After narrowing the search to nine candidates, Bao's team modeled the compounds' toxicity and pharmacological properties: how the compounds were likely to be absorbed, distributed, metabolized and excreted by hosts. The team found several potent inhibitors, offering a potential new path for designing treatments for diseases associated with bacterial adhesion. The findings are particularly significant considering the status of S. mutans as the principal cause of dental caries.