Light microscopy and chemical staining methods could help clarify how tooth cementum develops, a US scientist reveals. This thin layer of mineralized tissue that covers the roots of teeth can be one of two types: acellular or cellular. Since little is known about the tissue itself, Brian Foster of the National Institutes of Health, Maryland, USA, compared different staining techniques to differentiate acellular and cellular cementum from surrounding dentin, bone and ligament structures in mouse, porcine and human teeth. He found that Alcian blue stain and nuclear fast red counterstain were the most effective in distinguishing between cementum and surrounding tissues using light microscopy. Foster also found that using antibodies to highlight specific proteins in the tissue (immunohistochemistry) helped visualize the cementum layers and could provide insight into its biological development.

Genetic research into tooth-enamel formation reveals a mineralization front along which crystals form, US and Canadian scientists report. James P. Simmer and colleagues at the University of Michigan, USA, and McGill University, Canada, reviewed recent genetic studies which suggest that enamel formation, or amelogenesis, is closely linked to the activity of ameloblasts, the cells that initiate tooth growth. Based on laboratory studies, the classical theory of amelogenesis describes crystal growth on an extracellular matrix with mineral deposition governed by proteins. However, enamel appears to behave differently within the body. Studies on rodents suggest that the first mineral present in enamel is amorphous calcium phosphate (ACP), and that the initial enamel ribbons are not crystalline but flexible. A mineralization front, sustained by the ameloblast cell membrane, shapes and orientates the ribbons before they harden into rod-shaped crystals.

Oral bacteria that decrease mouth acidity by producing alkali are key players in preventing cavities, according to a review by Robert A Burne of the University of Florida and his colleagues. Mouths are colonized by hundreds of types of bacteria that form biofilms on teeth and contribute to either oral health or disease. Some of these bacteria decrease mouth acidity by metabolizing substances — urea and arginine — that are naturally present in saliva. Burne and colleagues reviewed evidence that these bacteria thereby encourage growth of cavity-preventing bacteria and help to remineralize teeth. They note that more research is needed to clarify whether cavity-free patients have different bacterial communities, or simply different mouth environments. Further studies could also determine whether oral health can be improved by supplementation with arginine or probiotics containing the helpful bacteria.

People who grind their teeth in sleep do not necessarily have unusual dental physiology, research from Germany shows. Michelle Ommerborn and co-workers at Heinrich-Heine University, Düsseldorf, in collaboration with an orthodontic dental practice in Langenfeld, Germany, have completed a study involving 58 patients with known sleep bruxism (grinding), and 31 control patients with no grinding symptoms. Following up on a previous pilot study, the team focused on 16 different aspects of dental physiology, from overbite of canines to the maximum left and right movement of the mandible. The team discovered that teeth grinders have a more pronounced slide from first contact of teeth on biting (centric occlusion) to full closure of all teeth (maximum intercuspation). However, none of the other parameters were found to be statistically significant, contradicting the earlier pilot study.

Gallachinensis extract (GCE), the major component of a traditional Chinese medicine, can protect teeth against caries, scientists show. For thousands of years, Gallachinensis has found use in traditional medicines ranging from antibacterial to anticancer agents. From a chemical analysis, a team led by Xue-Dong Zhou at Sichuan University in China and Jacob ten Cate at the University of Amsterdam in the Netherlands found that gallic acid accounts for 71% of GCE's major organic components. Through washing bovine teeth with either GCEor gallic acid, followed by an acid buffer,the researchers showed that these natural compounds are almost equally effective at inhibiting demineralization of tooth enamel. The author's suggest that gallic acid is the herb's anti-cavity agent, so could be added to food and drink to improve a population's dental health.

Chinese gall extract (Gallus chinensis) could be a useful adjunct or alternative to fluoride in preventing and treating tooth root cavities common in elderly people. That is what Guo Bin from Institute of Stomatology of Chinese PLA General Hospital, and co-workers from the State Key Laboratory of Oral Diseases at Sichuan University and Tianjin found after subjecting cattle teeth prepared with artificial root caries above and beneath the gum line to solutions of gall extract, a remineralization solution and deionized water in the laboratory. After a week's treatment, the researchers observed the teeth under a polarized light microscope and profiled their surfaces using a laser scanning confocal microscope. They found the repair of the dentine beneath the gum better with the gall extract than the remineralization solution. Above the gum, it was about the same.

The high prevalence of dental cavities and tooth decay (caries) in primary-school-age children in China is cause for concern, research shows. Tooth decay is considered a socio-economic problem, worsening as a country becomes richer. Zhi Chen, Min-Quan Du, and co-workers at Wuhan University in China, together with a colleague at Radboud University in the Netherlands, have conducted the first longitudinal study of dental caries disease in 7–8 year olds in Wuhan of central China. The team found that 8.7% of the participants had caries in their new adult teeth. Some 98.2% of the children had plaque, of which 67.4% were classed as medium to severe cases. 84.6% of the examined newly erupted first molar have medium to deep pits and fissures, which also increased the cariogenic risk. The researchers have called for rapid health education and improved dental services in China, as well as the possible use of protective sealants on children's teeth.

A combination of radiography and clinical tests is the best way to correctly identify C-shaped root canal systems, research from China shows. C-shaped root canal systems occur under molars, and have a ‘fin’ or web-like structure connecting individual root canals. Chinese dental patients have a high incidence of C-shaped root canal systems that require different techniques to normal root canal surgery during endontic treatment. Yan Wang and co-workers at Shandong University and Shandong Provincial Key Laboratory of Oral Biomedicine, China, completed a statistical survey to ascertain the most effective way to identify C-shapes using different methodologies. Their study was based on radiograph scans and clinical microscopic examination by dental professionals. The combination of methods revealed that approximately 41% of the native Chinesepatients examined have C-shaped root canals.

Angiosarcoma is an uncommon malignancy, which spread out from the endothelial cells of vessels. Scalp angiosarcoma with cervical lymph node metastasis is particularly rare. This article describes a rare case of angiosarcoma of the scalp, presenting as neck inflammation. Imaging procedures such as computed tomography (CT), magnetic resonance image (MRI) and ultrasonography (US) were not sufficient to diagnose this case. A needle biopsy provided an effective and accurate diagnosis of cervical lymph node metastasis. Additional observation and physical examination was required to diagnose the origin of the primary cancerous lesion. Once the angiosarcoma diagnosis was confirmed histologically, sequential weekly and monthly docetaxel (DTX) treatment was effective in preventing reoccurrence. Nonetheless, the optimization of angiosarcoma treatment remains a future goal. Although patients generally describe pain and swelling at the primary lesion site, this patient complained only of painful neck inflammation, without any indication of pain or swelling of the scalp. A revised diagnostic protocol should note that cervical lymph node metastasis of unknown primary origin may result from angiosarcoma of the scalp.

Low-grade myofibroblastic sarcoma (LGMS) is a rare, malignant tumor with myofibroblastic differentiation. Despite it being classified as a distinct entity by the World Health Organization, a few cases were reported in the oral and maxillofacial region. Here, a LGMS developed on the palate of a 73-year-old man who presented with a 1-cm tumor on the posterior border of the palate. Based on the histological and immunohistochemical features, a diagnosis of LGMS was established. The tumor was resected, and no recurrence was observed over 2 years. Although the tongue is the most preferred site for LGMS, it may occur in any region of the oral cavity.