Perioral muscle activity changes after Lip Bumper treatment.

AIM: This prospective non-randomised case-control study analysed lip muscle activity after Lip Bumper (LB) treatment thought surface electromyography. METHODS: The study group was composed of 40 young patients with a mean age of 10 years and 1 month, treated with LB in the lower arch, while 40 children who did not undergo any treatment, matched for sex and age with the previous sample, constituted the control group. Measurements were performed at the beginning and after 1 year for both groups. Electromyographic recordings were obtained in rest position and during the swallowing of 50 ml of water. RESULTS: In the study group, after 1 year of LB treatment, a statistically significant decrease in values was found; specifically, in upper lip muscle activities at rest position with the appliance in situ (p <0.002) and both with (p <0.001) and without (p <0.001) the appliance for the lower lip. CONCLUSION: One year of LB treatment significantly reduced lip muscle activities at both rest position and during swallowing compared with the untreated sample. These results indicated a potential short-term of upper and lower lip muscle adaptation to the new balance induced by LB treatment.

Dentin caries progression and the role of metalloproteinases: an update.

AIM: This review aims to summarise our understanding of the destructive role of acid environment and metalloproteinases in dentin caries progression using a review process. METHOD: The acids resulting from consumption of sugars by acidogenic and aciduric bacteria can cause demineralisation of the tooth surface, but are not able to cause caries-like lesions. The appearance of such lesions requires the activation of enzymatic proteolysis in an acidic environment for degradation of the dentin organic matrix, leading to cavity formation. Bacterial collagenases have long been considered responsible for organic matrix destruction; host cell-derived matrix metalloproteinases (MMPs) have recently been considered to be involved in the dentinal matrix destruction of carious lesions. DISCUSSION AND CONCLUSION: MMPs are initially synthesised as inactive zymogens to be activated in acid environment of dentinal fluid during the carious process, resulting in destruction of the collagenous matrix. The role of acid environment on enamel and dentin demineralisation and the role of salivary and dentinal MMPs in dentin progression of caries has encouraged general dentists to include the monitoring of oral environment not only by control of bacterial oral flora in caries treatment protocol, but mainly by inhibition of dentinal and salivary MMPs through the use of toothpaste and/or mouthwash containing specific active agents.