Host modulation therapy (HMT), as a treatment concept for periodontitis, aims to modulate the host immune responses during the pathogenesis of periodontitis. Various drugs have been evaluated as HMT, including subdose doxycycline (SDD), nonsteroidal anti-inflammatory drugs (NSAIDs), bisphosphonates, and cytokine receptors, to modify or modulate inflammatory mediators and associated signaling pathways in the immune-inflammatory response, as well as connective tissue breakdown and bone resorption. SDD, a member of the tetracycline drug family, has been reported to improve periodontal treatment outcomes by inhibiting periodontal breakdown through inhibiting MMPs. NSAIDs may suppress periodontal inflammation by reducing cyclooxygenase-2(COX-2) activity. Combined application of SSD and NSAIDs may achieve a better clinical outcome. Recent studies of HMT treatment have focused on the prevention of excessive inflammation by regulating mediators using endogenous lipid mediators. Local administration of bisphosphonates and histone deacetylase inhibitors can inhibit osteoclast activity and regulate bone tissue remodeling. Currently, SSD is approved by the FDA for periodontal treatment. Other drugs, such as COX-2 selective inhibitor, nonsteroidal anti-inflammatory drugs, bisphosphonates, triclosan and iNOS inhibitors, have good application prospects in the prevention and treatment of periodontal disease, and the mechanism and side effects of these drugs remain to be further investigated.
Parotid obstructions can cause repeated swelling of the glands. Previously, duct stones were thought to be the main cause of obstructions, but salivary gland endoscopy examinations have revealed the absence of stones or foreign bodies in the duct system of the parotid glands with obstructive symptoms. Diseases of the parotid gland with obstructive symptoms include chronic recurrent parotitis, non-stone chronic obstructive parotitis, Sj?gren′s syndrome, IgG4-related parotitis and radiation-induced parotitis. The mechanism of obstructions is unknown, and the disease course is prolonged. In this paper, based on a brief analysis of duct stenosis, distortion and mucus emboli, which may lead to parotid obstructions, a new perspective is emphasized: the duct system of the parotid and flowing saliva constitute a microflow field. Based on the principle of fluid mechanics, the flow of saliva in the flow field can be affected by the confluence, diameter changes, and twist of the ducts. This outcome results in changes in the low velocity zone, backflow, counterflow and turbulence; affects saliva flow and normal discharge; and causes symptoms of parotid obstruction. An analysis of the possible mechanisms of parotid obstruction using two variables, duct anatomy and saliva traits, helps explain the causes of nonstone parotid obstructions.
For patients with dento-maxillofacial deformities who receive orthodontic-orthognathic combined treatment, the conventional treatment approach is preoperative orthodontic-orthognathic surgery-postoperative orthodontics. However, with the development of techniques used in orthodontic and orthognathic treatment, the surgery-first approach (SFA), namely, orthodontic surgery-postoperative orthodontics, has been widely used currently and displays several advantages, such as improving the treatment efficiency and providing patients with more satisfaction. This review provides a brief discussion and review of SFA concerning its development, indications, advantages and disadvantages, outcomes and stability, and the application and research progress of SFA in orthodontic-orthognathic combined treatment for patients with maxillofacial deformity. The literature review results showed that compared with the conventional treatment approach, SFA has relatively strict indications, which usually include patients with skeletal class Ⅱ/Ⅲ malocclusion, skeletal open bite, and bimaxillary protrusion or patients with facial asymmetry but who require little preoperative orthodontic treatment or removal of the compensation of the dental arch, specifically as follows: ①well-aligned to mildly crowded anterior teeth, ②flat to mild curve of Spee, ③normal to mildly proclined/retroclined incisor inclination, ④acceptable arch coordination, ⑤extensive occlusal contact between the upper and lower dentition requiring at least 3 occlusal contacts. Any occlusion that may affect the outcome of surgery or final result of the overall treatment, as well as any disease that may jeopardize the healing process after surgery, is regarded as a contraindication. Furthermore, SFA has potential disadvantages, such as a possible higher incidence of complications, including unstable occlusion and malunion of bones, which still require further research to be confirmed. Most researchers believe that no significant difference occurs between the outcome and stability of the two approaches. However, currently, we still need a sufficient sample size of prospective studies to provide accurate evidence.
In recent years, the etiology of periodontitis has tended to be based on the theory of flora imbalance. That is, periodontitis is not caused by specific bacteria but by the breakdown of the oral flora balance, which leads to an immune imbalance. Imbalanced bacterial flora cooperate with each other to produce virulent factors that destroy organism tissues and induce immune cells to produce abnormal levels of cytokines, causing greater damage. This article reviews the initiation of a flora imbalance, the interaction between bacteria, the immune damage of the host and the prevention and treatment of the flora imbalance. The literature review shows that peroxidase released by inflammatory reactions, host immune responses to pathogenic microorganisms and some systemic factors, such as diabetes, can trigger flora imbalance. As a result, ion transport, substance synthesis and metabolism of bacteria change; virulence factors increase; and the oral flora balance is disrupted. Red complex bacteria enter gingival epithelial cells, produce adhesin, and selectively inhibit the expression of specific chemokines, which is beneficial for other pathogenic bacteria to enter gingival epithelial cells. Toxicity factors increase throughout the body, directly destroying body tissues and inducing innate and adaptive immune responses, thus causing related immune damage. The dysbacteriosis model of periodontitis provides a new idea for the prevention and treatment of periodontitis, such as using biological factors, bacteriophages, probiotics and other methods to reduce the number of periodontal pathogens to restore the steady state of periodontal flora.
Biodentine is a bioactive dentin replacement material whose main component is high-purity tricalcium silicate without dicalcium silicate. It has a shorter cure time; although it has a higher solubility, it hardly affects the volume of the material. It has a low X-ray barrier property, low porosity, high bulk density, and high compressive strength and is not affected by moisture or a dry environment. It has strong acid corrosion resistance, can increase dentin resistance, and has biocompatibility due to the lack of cytotoxicity. It has antibacterial activity against various bacteria, with strong antibacterial activity against Streptococcus sanguis. Since 2010, Biodentine has been widely used in clinical treatments such as dental restoration, pulp capping, pulpectomy, et al. In clinical applications, Biodentine is primarily used as a permanent dentin substitute or as a temporary enamel substitute within 6 months. As a new dentin substitute material with a short clinical application time, the long-term efficacy of Biodentine requires further follow-up observation studies.