Etiology and Pathogenesis- Local Factors, Occlusion, Epidemiology

local factors

-factors that influence periodontal health status at a particular site (or sites) with no known systemic effects

-not themselves etiologic factors

-anatomic contributing factors, restorative contributing factors, orthodontic factors

anatomic contributing factors

-proximal contact relation- loose contacts, uneven marginal ridges promote food trapping and create difficulty with hygiene

-cervical enamel projections and enamel pearls

-intermediate bifurcation ridge- convex ridge of cementum that runs from mesial to distal roots of mandibular molar

-root anatomy

-cervical enamel projections

-won’t have attachment of CT with enamel

-projects into furcation area

-enamel pearl

-tends to involve furcation defects

root anatomy

-palatogingival groove

-root trunk length

-root proximity

-root groove

root trunk length

-distance from CEJ to opening of furcation

-shorter means less distance to travel = get to furcation entrance sooner

-difficult to treat area

restorative contributing factors

-overhanging restorations

-margin location

-crown contours

-pontic form

-restorative materials

-overhanging restorations

-plaque retentive

margin location

-inflammation and/or uncontrolled bone loss if restorations impinge on biologic width

periodontal health is best achieved by placement of restorative margins ___

-supragingivally or at the gingival margin

pontic form

A) sanitary pontic- places the convex ridge-facing surface of pontic 3mm or more away from the tissue surface

B) ridge-lap pontic- concave intaglio surface straddling the ridge, difficult to clean adequately with floss

C) modified ridge lap- slightly concave intaglio surface on the facial aspect, but the lingual aspect is convex, allowing better access for plaque removal than ridge-lap

D) ovate- completely convex intaglio surface that extends into a prepared region of the soft tissue, dental floss able to pass in all dimensions, most often used in esthetic regions of the mouth

orthodontic contributing factors

-crowding

-malalignment

-brackets/bands

occlusal trauma

-injury or adaptive change in the periodontal attachment apparatus due to excessive occlusal force

primary v. secondary occlusal trauma

-primary: injury resulting in tissue changes from excessive occlusal forces applied to a tooth or teeth with normal support

-secondary: injury resulting in tissue changes from normal or excessive occlusal forces applied to a tooth or teeth with reduced support

signs of occlusal trauma

-mobility

-widened PDL

-fremitus (palpable or visible movement of a tooth when subjected to occlusal forces)

-occlusal wear

-widening of the PDL

-could happen if restoration is too high on occlusal

jiggling force study- normal periodontal tissues

-jiggling forces mimic human occlusal forces

-PDL adapts and widens

-once occlusal trauma force is removed, will go back to normal

-there is no bone loss

jiggling forces- suprabony and infrabony pockets

-suprabony: jiggling forces did not result in loss of CT attachment, occlusal adjustment reduces the width of the PDL and less mobile teeth

-infrabony: enhanced loss of CT attachment and further downgrowth of the epithelium, occlusal adjustment did not improve attachment levels

key facts related to occlusion

-excessive occlusal forces cannot induce pathologic alterations in supra-alveolar CTs and does not initiate loss of periodontal attachment

-in the presence of inflammation, occlusal trauma MAY accelerate periodontal breakdown

types and purposes of epidemiology

-descriptive: levels of disease, allocation of resources

-analytical: identification of risk factors

-interventional: modulation of risk factors, public health policy

prevalence v. incidence

-prevalence: occurrence (%) of the condition in the population at a given time point

-incidence: occurrence (%) of new cases over a time period

periodontitis- extent and severity

-extent: proportion of the dentition (% of sites) affected by the disease

-severity: magnitude of attachment loss or bone loss, expressed in mm or % of the root length

Scherp 1964

-periodontal disease is a major public health problem affecting 100% of the individuals after the age of 40 (likely an overestimation)

-the disease starts as gingivitis in young age and, if not treated, turns to destructive periodontal disease (last part not true)

-90% of the variance in the prevalence of the disease can be explained through oral hygiene and age (more factors than just these two)

Lindhe 1983

-looked at what happens if you don’t treat periodontal disease, looking at site level

-progression of periodontal disease in adult subjects (Sweden) in the absence of periodontal therapy

-6 year follow-up of 64 untreated patients with periodontal disease

-baseline to 3 years, only 4% showed an attachment loss of more than 2mm

-baseline to 6 years, 11% showed attachment loss of more than 2mm

-showed that not all sites progressed (as previously thought)

Loe 1986

Hugoson 2006

Wahlin 2018

epidemiology of severe periodontitis- current concepts

-1.1 billion cases of severe periodontitis globally

-higher prevalence among “developing” countries/regions

-an 8.5% increase in prevalence rate of severe periodontitis from 1990 to 2019

-global population growth primarily accounts for the increase