tion may reduce insulin resistance and thus lead to im- examining over 3,500 adult DM patients found that pa-
proved glycemic control. ³⁸ tients with DM had more severe periodontitis than those
without DM in the majority of studies. ⁴ In large epidemi-

Diabetes Mellitus: Potential to Impact ological studies of the Pima Indians of Arizona, who have
Periodontal Disease Severity the world’s highest prevalence of type 2 DM,^79,80 patients
Diabetes mellitus has long been known to have a signifi- with DM had a risk for developing periodontitis that was
cant influence on the periodontium and is viewed as a about 3 times higher than the U.S. average. Other studies
risk factor for both gingivitis and periodontitis, although of DM patients corroborate the greater extent and se-
it is clear that not all patients with DM have periodontal verity of periodontal destruction in these patients versus
disease. The relationship seems highly dependent upon non-DM controls when all other risk factors are taken
the level of glycemic control.⁶⁸ Just as DM patients with into account.^81,82 This higher prevalence and severity of
poor control are more likely to exhibit retinopathy, neu- periodontitis may also put these patients at higher risk
ropathy, and nephropathy, they are also at greater risk for for continued progression of periodontal destruction,⁸³
destructive periodontal disease. The current periodontal with type 2 patients having up to a 4-fold greater risk of
disease classification lists “diabetes mellitus-associated progressive periodontal bone loss than non-DM control
gingivitis” as a distinct disease entity.⁶⁹ Although there is patients.⁸⁴
no distinct diabetes-associated periodontitis in the cur-
rent classification, uncontrolled or poorly controlled DM As with gingivitis, the association between DM and in-
is considered a modifier of preexisting periodontitis that creased risk for the development and progression of
adjunctively enhances its severity. periodontitis appears to be related to the level of glyce-
mic control. Although the evidence is not complete,⁶⁸ lon-

Both children and adult patients with DM tend to have gitudinal studies have shown that patients with poorly more plaque-induced gingivitis than healthy individuals, controlled type 2 have 2. 9 times the risk of periodontitis⁸⁵ although this has not been shown in all studies.⁷⁰ Given and 11 times the risk of progressive bone loss⁸⁴ that nonsimilar levels of plaque accumulation, gingivitis is more DM patients have, whereas patients with well-controlled prevalent and severe in type 1 and type 2 DM patients DM have no increased risk for periodontal morbidity. DM than in non-diabetic controls,^71-73 with significantly more patients with poor or worsening control suffer greater gingivitis seen in patients with poorly controlled DM than increases in pocket depths, attachment loss, or bone in those with well-controlled DM or without DM.^73-76 Sup- loss than patients with well-controlled or relatively well-porting this relationship, gingival inflammation tends to controlled DM.^82,86-90 Other studies have shown nonsig-subside as glycemic control improves. ^52,75,76 More recent- nificant associations between diabetic control and peri-ly, a study of experimental gingivitis in type 1 DM patients odontal parameters,^91,92 and some older studies found no found that even patients with relatively well-controlled relationship at all.^93,94 The varied results may reflect im-DM develop gingivitis more readily than non-diabetic provements in treatment and assessment methodologies individuals because of a hyperinflammatory immune re- over the years, although many patients with poorly con-sponse, despite similar plaque levels and bacterial com- trolled DM have no major complications,^95-97 just as good position,⁷⁷ again implicating the systemic inflammation glycemic control is not a guarantee against developing present in the diabetic state as an etiology for periodontal periodontitis. disease.

The association between glycemic control and periodon-

Most evidence also suggests that type 1 and type 2 DM titis may parallel the relationship between DM and other increase the risk of periodontitis. Of 21 epidemiological classic complications. In the Diabetes Control and Com-studies in children, adolescents, and adults with type 1 plications Trial (DCCT), 1,441 type 1 DM patients on a DM, 95% found a greater prevalence, severity, or extent tight glycemic control regimen had less retinopathy, ne-of periodontal destruction in DM patients than in non-DM phropathy, and neuropathy over 6. 5 years than DM pa-controls.⁷⁸ Age is a factor in the prevalence of periodon- tients using conventional glycemic-control methods.⁹⁵ titis: type 1 DM did not affect prevalence in subjects un- Subsequently, similar reductions in the risk of diabetic der age 12; however, during adolescence and middle age, complications have been shown in over 5,000 intensively-the prevalence increased more in DM patients than in managed type 2 patients.^96,97 controls.⁷¹ Another systematic review and meta-analysis