Apical periodontitis is an inflammatory process located around the apex of the root. It is mainly caused by a microbial infection of the pulp space. Diabetes mellitus and tobacco smoking are modulating factors that may influence the healing of apical periodontitis. Present studies have disclosed an association between smoking and apical periodontitis and diabetes mellitus and apical periodontitis. The aim of this study is to compare the healing of periapical bone in smokers and non-smokers and patients with diabetes mellitus type 2 and healthy participants. The hypothesis of this study is that smokers and patients diagnosed with diabetes mellitus will experience slower healing with a lower success rate in comparison to control groups. Apical periodontitis will be diagnosed through means of clinical examination and radiological analysis. Healing of apical periodontitis will be determined using periapical radiographs utilizing periapical index. This prospective study will contribute to the development of clinical guidelines concerning smokers and patients with diabetes mellitus type 2.

Apical periodontitis is an inflammatory process located around the apex of the root. It is mainly caused by a microbial infection of the pulp space. Diabetes mellitus and tobacco smoking are modulating factors that may influence the healing of apical periodontitis. Present studies have disclosed an association between smoking and apical periodontitis and diabetes mellitus and apical periodontitis. The aim of this study is to compare the healing of periapical bone in smokers and non-smokers and patients with diabetes mellitus type 2 and healthy participants. The hypothesis of this study is that smokers and patients diagnosed with diabetes mellitus will experience slower healing with a lower success rate in comparison to control groups. Apical periodontitis will be diagnosed through means of clinical examination and radiological analysis. Healing of apical periodontitis will be determined using periapical radiographs utilizing periapical index (PAI). One observer will be calibrated by evaluation of periapical status in 100 reference radiographs according to periapical index scoring system .

In each participant only one tooth will be included in the study. This will be first tooth submitted to endodontic treatment according to diagnostic priority. The survey will include only teeth with adequate endodontic treatment according to following criteria: post-operative periapical radiograph demonstrating adequate length and homogeneity of root canal filling (no visible voids, one millimeter shorter than radiologic apex) , and clinically and radiologically adequate permanent crown restoration. Participants will attend clinical and radiological follow-up in six months and one year following root-canal treatment to assess healing rate. In diabetic participants glycemic control will be determined according to the level of glycated hemoglobin, which is routine procedure in these patients. In smokers, intensity and duration of smoking habit will be recorded. This prospective study will contribute to the development of clinical guidelines concerning smokers and patients with diabetes mellitus type 2.

Inclusion Criteria

1. Influence of smoking habit on apical periodontitis healing after non-surgical endodontic treatment

   • Smoker group- everyday cigarette smoking habit, older than 18 years
   • Control group-healthy non-smoker patients, older than 18 years, paired with smoker group according to age and sex

2. Influence of diabetes mellitus on apical periodontitis healing after non-surgical endodontic treatment

   • Diabetic group-patients having type 2 diabetes mellitus, older than 18 years, non-smokers
   • Control group-healthy patients, non-smokers, older than 18 years, paired with diabetic group according to age and sex

Exclusion Criteria:

1. Influence of smoking habit on apical periodontitis healing after non-surgical endodontic treatment

   • Smoker group-systemic disease, pregnancy, taking medications that interfere with bone metabolism and immunologic response, former and occasional smokers
   • Control group-former, occasional and present smokers,systemic disease, pregnancy, taking medications that interfere with bone metabolism and immunologic response

2. Influence of diabetes mellitus on apical periodontitis healing after non-surgical endodontic treatment Diabetic group-pregnancy, taking medications that interfere with bone metabolism and immunologic response, smokers Control group-patients having diabetes mellitus, pregnancy, taking medications that interfere with bone metabolism and immunologic response, smokers

Cohort of patients attending Dental Clinic of the Rijeka Clinical Hospital Centre requiring root canal treatment of at least one tooth with radiological diagnosis of apical periodontitis.