The paper is interesting and relevant. It is not a small sample and that is important to generalize the results. However, there were several points that has to be considered:

Introduction: Why there is so much emphasis to the oral health in the introduction? are there no other health areas to connect the Sense of Coherence?
Statistical analysis: What is the estimator ML? why these statistical programs were selected? I think the statistical analysis section could be explained better. A validation of a scale is the main point, the statistical analysis.
Results: In the abstract the authors indicate an internal consistency of 0.63, and correctly indicate that due to this result this instrument is questionable. However, in the results section they do not indicate this, moreover, they mention that the scale showed a moderate correlation between the different items in the same test.
This is not how you report correlations. This is an example of how you should do it: Correlations are reported with the degrees of freedom (which is N-2) in parentheses and the significance level: The two variables were strongly correlated, r(55) = .49, p < .01. https://my.ilstu.edu/~jhkahn/apastats.html
Discussion: In the discussion they mention again that the instrument reproduced a moderate value. The literature indicates that any value of .6 is poor/questionable. It is ok if the authors mention this, is not problem to publish neutral or negative results, but not to have confusing data inside the paper, it was hard for me to understand, I had to read it again a couple of times until I understand what the authors were doing wrong.
Part of the discussion is related to defend that the lower alpha coefficient is not a reliable measure. I read this and I think this is not the proper to arrive the issues presented in the instrument. I do not see a critic to the instrument. 
Very important and not mentioned at all. There is a not so old article of Eriksson and Mittelmark, 2016, that describes the SOC, but also mentions flaws of the SOC-13. I do not see a clear discussion and limitation here, nor a proper analysis of the results.  https://link.springer.com/chapter/10.1007/978-3-319-04600-6_12
