Periodontal Disease and Preterm Birth

Gazabpreet Bhandal1st year Resident, Dept. of Periodontics

Outline

• Pathogenesis of Periodontitis

• Pathogenesis of Preterm Birth

• Inter-relationship between Periodontitis and Preterm Birth

• Conclusion

Periodontal DiseaseAn infectious disease resulting in inflammation within the supporting tissues of the teeth, progressive attachment and bone loss and is characterized by pocket formation and/or recession of the gingiva.

RISK FACTORS:

1. Bacterial factors

2. Smoking

3. Age

4. Host Response Related

- Systemic ( eg: Diabetes, Pregnancy )

- Stress

- Genetics

* Periodontal diseases are “a specific mixed infections which cause periodontal destruction in the appropriately susceptible host” (Offenbacher 1996)

Bacterium involved:

Microbial complexes in subgingival plaque: Socransky et al, 1998

Pathophysiology of the Periodontal Disease

Periodontal

Disease

Direct effects of bacteria:Inc. edema

Inc. GCFProteases, Collagenases,

Fibrinolysin, phospholipase A

H2S, NH3

Genetic Risk Factors:Host Immuno-inflammatory

responseConnective tissue

and bone metabolism

Environmental and Acquired Risk factors

Indirect Effects of bacteria:

PMNsLymphocytesMonocytesFibroblasts

LPS Pro-inflammatory

cytokines: (IL-1,IL-6,IL-8,TNF-α, PGE-2, MMPs)

Organic Molecule Function

Collagenase Breaks peptide bonds in collagen.Virulence factor

Fibrinolysin Inactivates fibrin molecules occurring in undesirable exudates

Phospholipase A Involved in breakdown of phospholipids to Fatty Acids

MMPs Zn dependent endopeptidases responsible for degradation of extracellular matrix

TNF-alpha Adipokine ; Produced chiefly by activated macrophages.

LPS Endotoxin; binds to CD14/TLR4/MD2 receptor complex stimulates pro-inflammatory cytokines and NO.

CD14/TLR4/MD2 receptor complex

Pathogenesis

Low Birth Weight Preterm Birth

• According to WHO, preterm birth is defined as delivery before 37 completed weeks of gestation.

• Low Birth Weight is defined as weight less than 2,300gms

Pathophysiology of Preterm Birth

Chorioamnionitis

• Chorioamnionitis or intraamniotic infection is an acute inflammation of the membranes and chorion of the placenta, typically due to ascending microbial infection in the setting of membrane rupture.

• Overall, 1-4% of all births in the US are complicated by chorioamnionitis.

Routes of chorioemnionitis

Ascending InfectionMicroorganisms residing in the

external genitalia gain access to the

amniotic sac

Debilitatio

n and

rupture of the

sac

Spread of the

infectious

agent into the

amniotic fluidAspiration/

swallowing of the micro-

organisms

Immune response

triggered on the amniotic

sac by infection

Induction of labor

Role of pro-inflammatory cytokines in preterm birth

Infected sites (eg: Periodontium) or Placenta

Pro-inflammatory cytokines (IL-1, IL-6, TNF-alpha)

Stimulation of PGE2 synthesis by human placenta and chorioamnion

Induction of Abortion or labor

• Examination of effect of P.gingivalis on pregnant hamsters revealed elevation of PGE2 and TNF-alpha levels (Collins 1994)

PGE2 synthesis

Inter-relationship between Periodontal disease and Preterm Birth

Offenbacher (1996), Jeffcoat (2001), Jarjoura (2005) : Proposed that periodontal disease is a risk factor for PLBW.Scaling and Root Planing in pregnant females reduced the incidence of preterm birth (Jeffcoat 2001)

Negative evidences:

• Davenport et al(2002), Noack et al(2004), Veltore et al (2008), Rajapakse et al(2005): No evidence for association between periodontal disease and preterm low birth weight.

• Hoolbrook et al(2004), Moore et al(2005) : Reported no association between the severity of the periodontal disease and pregnancy outcome.

• Buduneti et al(2005): No difference in dental and periodontal parameters between cases and controls.

Sources of Bias:

1. Variation in the definition of the periodontal disease.

2. Variation in the definition of the Adverse Pregnancy Outcomes (APOs)

3. Confounding factors (eg: socio-economic status and smoking)

Conclusion

• There are numerous studies that support a positive association between periodontal disease and preterm birth but unfortunately trials of antibiotic treatment have not shown any significant decrease in the rate of preterm birth.

• The effectiveness of antimicrobial therapy in eradicating these infections suggests that its failure to prevent preterm births is evidence that the infections alone are not causal.

• Longitudinal studies are warranted to establish a stronger and causal relationship between the two.