evidence of increased protein oxidation
Dean V. Sculley and Simon C. Langley-Evans
In this work by Sculley and Langley-Evans, the main focus of the research was to determine if there is any linkage found between salivary composition, specifically its antioxidant content, and the incidence of periodontal diseases such as gingivitis or periodontitis. Both of these periodontal conditions were discussed in this publication, as well as in my first Blog Assigment on gingiva. The study also considers a number of possible factors which may play a role in the individual differences observed in saliva oxidative capacity, and looks to investigate how in turn they may increase the risk of such conditions. Through this study, a number of findings have important implications in the ongoing research regarding periodontal health.
The study was completed in 2001-2002. 129 subjects were involved, all of which were taken after general check-ups at a single clinic located in the United Kingdom. All subjects were Caucasian, ranging from ages 39-76, and the group included an equal number of both male and female participants. To create a more representative sample for the research focus, those found to be taking any nutritional supplements or those who had previously received complex dental treatments were not permitted to be included in the experiments. These criteria allowed for a more optimal study group for examination practices.
Before saliva sampling was initiated, all subjects went through a preliminary gum tissue assessment. This was completed using the Community Periodontal Index of Treatment Needs (CPITN) system. These measurements were used to determine oral health and the incidence/risk of periodontal disease on a universal scale. Whole saliva samples were then collected over a 5 minute duration using specific collecting tubes without any form of oral stimulation. In this way, samples would most accurately match the naturally occurring saliva composition.
Once collected, samples were analyzed using a Total Anti-oxidant Activity (TAA) assay, as well as measurements for individual antioxidant components commonly found in whole saliva samples, and saliva/antioxidant flow. These antioxidants of the saliva are a very important contributor to good oral health as they are involved in the destruction of harmful bacteria that cause periodontal disease.
The samples were also tested for total protein carbonyl concentration. These carbonyls are indicative of oxidative injury as they result from free radicals and the major damages they cause to the gingival tissue. Therefore, a higher TAA and a lower protein carbonyl concentration would indicate a healthy and most optimal saliva composition.
The results indicate a number of interesting trends that exist when analyzing the functional oxidative capacity of saliva and its specific composition. One finding suggests that there is a relationship between saliva content and gender. Comparing the male and female subjects, females were generally found to have a lower overall total antioxidant activity and a higher protein carbonyl concentration, indicating that sex may play a role in both saliva composition and related risk of periodontal disease.
The research also indicated a positive correlation found between smoking subjects and the incidence of periodontal disease, where higher protein carbonyl levels were observed in the smoking subjects. Also, none of the smoking subjects were classified as having mild/no disease, indicating the negative impacts of smoking on oral health.
Based on these results, Sculley and Langley-Evans suggest that a decline in oxidative activity of the saliva may not be considered a known causal factor in periodontal disease, however it may very well play a major role in the progression of a previously onset disease, causing a continuation of damage to the gum tissues.
A number of issues were also brought up by the researchers. One issue is that women generally produce less saliva than men, which may affect results of antioxidant content of saliva, as well as flow rate. Also, the researchers were concerned that the values of antioxidant concentrations reported may be artificially high due to leakage of blood plasma antioxidants as a result of bleeding during the initial gum assessment.
In a personal critique of this publication, Sculley and Langley-Evans provide clear evidence of the hypothesis tested. Using practical methodology and clear measurement techniques the findings accurately model the relationship between salivary oxidative activity and periodontal disease. The article does a great job in providing important information on oxidation processes and harmful periodontal conditions that can occur in the oral cavity, which can have important implications for both colleagues as well as members of the general public interested in the maintenance of their own oral health. Furthermore, the material contained within this publication also stresses the major impact of periodontal disease both in the numbers affected today as well as the many detrimental effects associated with such conditions. Well recognized research on such a serious issue may stimulate interest in fellow researchers, which may help in gaining much needed knowledge in this field. This in turn can help others who read this publication understand the importance of taking action when it comes to oral hygiene.
However, in reading this publication, one issue does arise, specifically in the sampling of subjects. All 129 subjects involved in this study were said to be taken from the same dental clinic after routine check-ups, which may introduce imprecision in the results found. To increase accuracy of the results, subjects should be found through a broader range of venues to create a more representative sample. In this way, subjects used in the study may include those with both good as well as poor oral health practices, such as those who may not attend regular dental visits or do not pratice regular brushing and flossing. Also, possible factors such as socioeconomic status or financial resources may be studied to see if they play a role in salivary oxidative decline. When finding subjects outside the clinic, this may include individuals who are unable to afford regular check-ups.
