This study was carried in the Ohio State University College of dentistry and published in 1998. This study began by reviewing a previous study on stress and health. This found that people undertaking a chronically stressful activity show characteristic changes in their blood chemistry and take longer to heal minor wounds than do people who are not under conditions of stress. Therefore, it addressed the effects of a commonplaces stressor, examination stress, on wound healing.
In this study, it was used experimental approach. In the control group, the first wounds were placed on the hard palate of 11 dental students during summer vacation. In the experimental group, the second wounds were placed on the contra-lateral side of the hard palate of the same 11 dental students during 3 days before the first major examination. A within-participants design was employed in this experiment. Two independent methods assessed healing. They were daily photographs and a foaming response to hydrogen peroxide.
Students took an average of 3 days longer to completely heal a small, standardized wound. Production of interleukin 1? messenger RNA declined by 68% during examinations, providing evidence of one possible immunological mechanism. These data suggested that even something as transient, predictable, and relatively benign as examination stress had significant consequences for wound healing. After summarizing this study, let’s have a critical review on the methodology and findings and interpretation in this study.
For the methodology, it was an experimental research approach in nature. It was appropriate because this study measured the variables objectively and achieved the purpose of this study. The healing of the wound was dependent variable. It was operationalized and was monitored visually by measuring its size and by a chemical test that indicated how ‘open’ the wound was. The stress level was the independent variable. Students’ stress level was lower in summer vacation. It was confirmed by Perceived Stress Scale in the questionnaire for every student.
Therefore, the variables were appropriate for the hypothesis. For the participants in this study, eleven healthy dental students were recruited from the Ohio State College of Dentistry. They had the basic knowledge about handling the wounds. Since the effect of healing oral wounds were controlled by the participants, it was better to have the knowledge of this area to avoid affecting the effect of healing wounds by individual differences. Also, they were instructed not to use rinses or other special home care other than normal oral hygiene.
For the ethical issues, the Ohio State Biomedical Research Review Committee approved the project. All the students gave written informed consent before participation. This complies with ethical rules that research works that involve human subjects and animals should be carried out in accordance with high ethical standards set by various ethics committee. For controlling the confounding variables, all the participants were healthy dental students and were instructed not to use rinses or other special home care other than normal oral hygiene.
It eliminated the individual differences to affect the effect of healing wounds. In this study, a within-participants design was employed rather that between-participants design in this experiment because the effect of healing wounds was much affected by individual differences. Using within-participants could eliminate the individual differences. Also, the participants were also asked about their other health-related behaviors to see if the stress was come from examination or other health-related behaviors.
In this study, the researcher could find no evidence that these effects could be due to other factors such as alcohol intake or sleep deprivation that might vary during exams. However, there were two major limitations for this research. Firstly, the sample size was too small. There were only 11 participants to take part in this research. The result was significant may be due to the sampling error of small sample size. Therefore, sample size is needed to increase to make sure it is large enough to reduce the sampling error.
Then, the result of research will be more valid. Secondly, all the control groups were conducted before the experimental group. The second placing of the wound in experimental group was approximately six weeks later and three days before the first major academic examination of the term. It might affect the result due to the order effect. It is better to conduct one more control groups after two months of the examination. For the findings and interpretation, the data obtained in the study were properly described.
This was in the form of graphs and was further explained in words. Multivariate analysis of variance (MANOVA) was used as the statistical methods in this study. This was appropriate because they were used to assess within-subject change over time. If more than one dependent variable was measured, MANOVA was used. Here both the change of visual judgement of wound size and the reaction to hydrogen peroxide were measured and hence a MANOVA was employed. The interpretations made in the study were derived properly from the results obtained.
One graph showed that the wound sizes were lesser during summer vacations than during examination period. The other graph showed that it took less days to heal during low stress and more days to heal for wounds during high stress periods. In this study, it also showed the mean, F score and p-value of wound size. It indicated that there were significant differences between vacation and examination wound size. For using F score and p-value, it also showed that whether some variables, such as alcohol intake, reported significant difference between experimental group and control group or not.
It was important. If these two groups were different in some characteristic, the effect of healing wounds might due to other factors and not because of stress. Although some variables in the study were controlled and there was little chance for the data collected to have alternative interpretations, the result was significant may be due to the sampling error of small sample size. Therefore, sample size is needed to increase to make sure it is large enough to reduce the sampling error. Then, the result of research will be more valid.
The results of this particular study were related to relevant theories and/or past research. As discussed in the beginning of their study, an earlier study in their laboratory showed that severe and prolonged psychological stress was associated with poorer wound healing. This finding was further verified with this new study conducted. The results of this study could help other dentists and the medical field in general in understanding wound healing and guide them in finding ways to further speed up the wound healing process.