International Endodontic Journal, 48, 95-102, 2015 L. Wan et al
The inter-relationship of periodontal and endodontic diseases has been a subject of speculation because of the close connections between the periodontium and pulp tissue in embryonic origin, anatomy, and function. The literature concerning this relationship has been contradictory across the years. The reasons for this inconsistency are numerous, including the lack of definitive case selection criteria, lack of uniform documentation of the case histories, failure to include appropriate controls, as well as variability in study design protocols.
Wan et al, IEJ 48:95-12, 2015, set out to investigate the effect of chronic periodontitis on dental pulps by assessing the histology of the pulps of teeth with moderate-to–severe periodontitis.
The American Academy of Periodontology characterizes moderate periodontitis as probing depths (PD) 6mm and AL >/= 5mm. 242 teeth from 162 patients with chronic periodontitis were collected, 61 with moderate periodontitis and 181 with severe periodontitis. The control group consisted of 54 teeth from 27 patients without periodontal disease removed for orthodontic reasons.
Teeth with caries, restorations, attrition, erosion, primary occlusal trauma or clinical signs of acute periodontal or pulpal disease were excluded from the study as were smokers. No periodontal treatment had been received in the previous year. The teeth were evaluated for mobility, PD, and AL prior to extraction. The study teeth were fixed in 10% buffered formalin, decalcified with EDTA, sectioned at 5 microns, and stained with H&E prior to microscopic evaluation by 2 independent, blinded, pathologists.
The pulpal morphological changes of the teeth were categorized as degree I through IV as defined by Mazur & Massler in 1964, with degree I showing relatively normal cell and ground substance levels but abnormally prominent and abundant capillaries (early signs of inflammatory changes), degree IV being necrotic, and degrees II & III showing increasing levels of odontoblastic layer disruption, fibrous tissue replacement, inflammatory cells, vacuoles, and calcifications.
The authors found that in the moderate periodontitis group, 26% were degree I and showed minimal pulpal changes, 29% degree II, 28% degree III, and 16% degree IV (necrotic). In the severe periodontitis group, 8% were degree I, 23% degree II, 28% degree III, and 40% were degree IV (necrotic). The observed trend of increasing pulpal degeneration reflected the trend of increasing PD and AL as well as tooth position from anterior to posterior with molars showing more severe pulpal degeneration than incisors. Only 2% of the control teeth showed minor histological changes in the pulp.
Wan et al concluded that both moderate and severe periodontitis showed histological degeneration of the pulpal tissue with a significant association between severity of pulpal and periodontal changes.
So what might be the link between pulpal and periodontal disease. Exposure of the dentinal tubules to the oral microbiota and their breakdown products would be the most obvious pathway. We know from anatomical studies that dentinal tubules are more numerous and larger in the coronal root segments. Long-term exposure of the roots, especially in teeth that had the cementum removed through scaling and root planning, could lead to bacterial penetration of the tubules resulting in a pulpal inflammatory response. Exposure of lateral canals would be another major point of penetration for bacteria, especially in the furcation area of molars.
The take home message is we, as clinicians, should not be surprised by unexpected pulpal degeneration and symptoms in teeth with a history of moderate to severe periodontal disease, whether active or not, and regardless of the degree of tooth restoration. Indeed we probably should be appraising our patients of that distinct possibility as well as the possibility that scaling and root planning, though important and necessary treatment protocols to maintain a healthy periodontium, may inadvertently invite unwanted pulpal changes.
About Dr. Howard Bittner, DMD, CAGS
Dr. Bittner was in private practice in general dentistry for 11 years in Langley prior to his Endodontic specialty training. He has been practicing the Dental Specialty of Endodontics since 1995.
In his free time, Dr. Bittner loves to participate in a variety of sports including most recent, golfing! He also enjoys being a grandfather to 4, which if you ask him is just the best!