Periodontitis is a chronic multifactorial infectious disease of the supporting tissues of the teeth (1
). It is estimated that between 10 and 15% of adults from 21 to 50 years of age and about 30% of subjects >50 years of age have severe periodontitis (2
). Clinically, patients suffer from gradual loss of tooth attachment in the alveolar bone leading to periodontal pockets, receding gums, loose teeth, and eventually tooth exfoliation, which may result in changes in diversity of food uptake, possibly affecting general health (4
). Often gums are red and swollen, bleed easily, and patients with periodontitis suffer from bad breath.
Treatment of periodontitis includes mechanical removal of supra- and subgingival bacterial plaque with scalers, curettes or ultrasonic devices (scaling and root planing [SRP]), and intensive oral hygiene instructions for the patient. A close to ideal oral hygiene regimen is the only way to prevent formation of new dental plaque deposits and re-infection of the subgingival tissues. The routine use of systemic or local antibiotics as an adjunctive therapy to SRP is still controversial in terms of improvement of clinical periodontal status (5
). Surgery regularly is needed to reduce or eliminate deep residual periodontal lesions.
Diabetes and periodontal disease are two chronic diseases that have long been considered to be biologically linked. A large amount of case reports, cross-sectional studies, longitudinal studies, and reviews report the adverse effects of diabetes on the onset, progression, and severity of periodontitis (8
). The prevalence of periodontitis in diabetic subjects is estimated to be double or even triple the number in the normal population (10
). It has been suggested that hyperglycemia and resultant advanced glycation end product formation, which is one of the several pathways that is thought to lead to the classic microvascular and macrovascular complications of diabetes, are also involved in the pathophysiology of periodontitis in diabetic subjects (8
There is a growing body of evidence supporting the fact that the periodontal infection with gram-negative microorganisms (11
) adversely affects glycemic control (9
). Thus, it is now acknowledged that due to untreated or inadequately controlled moderate-to-severe periodontitis, the systemic inflammatory burden may be increased. For example, in periodontitis patients without other apparent diseases, C-reactive protein (CRP) levels are higher compared to subjects without periodontitis (14
). Similarly, it has been suggested that a microbiological imbalance in the gut may increase the gram-negative bacterial load, which, through lipopolysaccharides leakage into the circulation, also increases the systematic inflammatory burden. The increased inflammation eventually triggers insulin resistance (15
More direct evidence regarding the effects of periodontal disease on glycemic control of diabetic patients comes from intervention studies using periodontal therapy. Since the beginning of the 1990s, several studies have investigated the association between periodontal therapy and the improvement of glycemic control in diabetic patients. For example, Iwamoto et al. (17
) showed that periodontal treatment in type 2 diabetic patients is effective in improving metabolic control. However, the latter and many other studies are uncontrolled, provide conflicting data, and report short-term results (<3 months). Because of the chronic nature of the development, progression, and severity of complications in diabetic patients, only longer-term results of periodontal treatment are meaningful. Therefore, we put the hypothesis forward that if periodontitis is causally related to the worsening of parameters of diabetic patients, then periodontal treatment should improve glycemic control.
Our aim was to perform a systematic review of intervention studies to answer the question of whether periodontal treatment affects the general health of diabetic patients by improving glycemic control compared with no periodontal treatment after at least 3-month follow-up.