Robotic surgery has shown promise for head and neck diseases, although more research is needed before it supplants traditional approaches. In a review article, En Luo and colleagues from Sichuan University’s West China Hospital of Stomatology in Chengdu discuss the history of robot surgical systems and the recent growth in popularity of such techniques for treating oropharyngeal cancer, cleft palates, craniofacial asymmetries and other conditions that require maxillofacial surgery. The authors describe how robot-assisted surgery in the head and neck region can result in less blood loss, fewer complications, shorter hospitalizations and better cosmetic results than conventional or endoscopic surgery. However, robotic surgery is expensive, takes longer to perform and lacks the human touch of a trained surgeon. More prospective trials are needed to determine if robotic surgery is truly superior.

Acidic microenvironments created by bacterial clusters thriving in a polysaccharide matrix could be behind localized tooth decay. Jin Xiao of the University of Rochester Medical Center and Geelsu Hwang of the University of Pennsylvania with colleagues in the US mapped acidity changes across tooth enamel caused by the microstructure of dental plaque: a film of bacteria and the polysaccharide matrix they secrete. Using fluorescence microscopy, they studied the 3D architecture of plaque that formed on human enamel specimens exposed to sugar solutions. They also measured acidity levels and surface roughness on the enamel. Enamel exposed to sucrose revealed densely packed bacterial clusters surrounded by polysaccharide matrix, creating localized acidic environments and deep lesions on the enamel surface. Biofilms on enamel exposed to glucose or fructose did not form organized bacterial clusters.

A combination of tiny gas-filled bubbles and ultrasound radiation can be used to deliver anti-inflammatory agents into periodontal tissue. The treatment produces pores in the surface of cells, facilitating the passage of therapeutics. Yuji Ishida of the Tokyo Medical and Dental University and collaborators successfully used the technique to transfer specific decoy oligodeoxynucleotides (ODN) into the oral tissues of healthy mice. These ODN are short stretches of genetic material that block the action of a key immune response modulator, preventing the expression of inflammatory proteins. Previous studies have demonstrated the clinical utility of this method in arterial disease; however, Ishida’s team show that ultrasound and microbubble treatment with decoy ODN reduces the expression of inflammatory proteins in periodontal tissue. The method offers a promising, noninvasive method to treat inflammatory oral disease.

A standardized approach for imaging the bones of the rodent jaw enables consistent collection of accurate structural data across specimens. Micro-computed tomography (micro-CT) is a widely used and reliable technique for visualizing skeletal structure, but its performance and its reproducibility is lower in the more heterogeneous bone that forms the upper and lower jawbones. To address this need, researchers led by Katleen Vandamme of the University of Leuven in Belgium have devised a protocol for the quantitative micro-CT analysis of rat jawbones. They identified multiple regions of interest in each bone that can be readily compared, and which are most likely to be structurally affected over the course of an experimental intervention. This protocol broadens the applicability of micro-CT for the analysis of rodent anatomy, and the authors propose that their approach should be similarly extensible to other species.

Certain populations of bacteria found in saliva during dental implant procedures are associated with implant failure and bone loss. In non-submerged dental implant surgery, missing teeth are replaced with prosthetic teeth attached to screws implanted into bone. While these procedures are largely safe with predictable outcomes, some patients show bone loss around the implant site. Quan Yuan of Sichuan University, China, and colleagues analysed the bacterial content of saliva from 100 patients and found that the proportions of specific bacterial species in the samples bore significant correlation to the amount of bone loss the patients suffered. The team’s findings indicate that certain species of bacteria may be associated with poor dental surgery outcomes and provide a starting point for researchers investigating dental implant rejection.

Oral clefts: Distinct genetic profiles characterize subtypes. Oral cleft subtypes are characterized by distinct gene profiles that may reflect differing genetic causes. Oral clefts, the most common congenital defect in humans, are associated with a large number of genes. Noriko Funato and Masataka Nakamura at the Tokyo Medical and Dental University, Japan, aimed to identify the genetic differences underlying the diverse nature of this disorder by grouping and analyzing the genes associated with different oral cleft subtypes according to their known functions. They found that different oral cleft subtypes were associated with genes with distinct functions. In particular, genes linked to the cleft lip and/or palate subtype were developmentally and genetically different from those of other oral cleft subtypes. A better understanding of the underlying genetic causes of oral clefts will allow for improved diagnosis and prevention.

Using citric acid in combination with ultrasonic rinsing helps flush out root canals prior to completing treatment. Calcium hydroxide, Ca(OH)₂, is used to eliminate microbes from root canals during treatment. However, residual Ca(OH)₂ left behind once treatment is complete can reduce the effectiveness of sealants and weaken dentin bonds. Hui Yang and Tao Hu at Sichuan University in Chengdu, China, and co- trialled novel ways of removing Ca(OH)₂ from curved root canal systems. Using synthetic root canal models and extracted human teeth, the team used different rinsing chemicals and techniques to clean root canals of different shapes. They found that citric acid was most effective, particularly when combined with ultrasonic rinsing. This technique agitated and loosened residues left in the root canal wall, allowing for a cleaner finish.

A low-viscosity resin infiltrant combined with a flowable composite resin can effectively seal fissures in premolars and molars. A team headed by Andrej Kielbassa at Austria’s Danube Private University in Krems compared two treatments for sealing fissures in extracted human premolars and molars having occlusal caries (decay on biting surface of teeth). Comparing the infiltration and microleakage of a low-viscosity resin combined with a flowable composite resin (RI/CR) with the flowable composite resin (CR) alone, they found that no parts of the caries lesions were infiltrated in the CR group. In the RI/CR group, infiltration was uniformly substantial and microleakage was lower. The resin infiltrant evidently provided a stable basis for the flowable CR, enhancing the quality of fissure sealing. The combination treatment appears promising for clinical control of occlusal caries.