Smoking Influence on Apoptosis in Periodontitis
Condition: Chronic Periodontitis; Aggressive Periodontitis
MeSH terms: Periodontitis; Chronic Periodontitis; Aggressive Periodontitis; Aggression
Study type: Observational

Summary: 
      Apoptosis is an evolutionary form of physiological cell death. Studies suggest that apoptosis
      is involved in the pathogenesis of periodontal diseases. Human gingival fibroblasts (HGF)
      have an important role in the periodontal immune response. It is believed that HGF can be
      diminished and/or eliminated by means of apoptosis.

      Smoking is one of the most common risk factor of periodontal disease. Studies indicated that
      smoking can increase the risk of periodontitis by enhancing the apoptosis of gingival
      fibroblast.

      The purpose of this study is to determine and to investigate apoptosis of HGF in gingival
      biopsies collected from smokers and non smokers who are diagnosed with chronic periodontitis
      or aggressive periodontitis.

      Eighty subjects will be invited to participate in this study. Patients will be allocated into
      four groups (20 patients each). Gingival biopsies will be obtained from the base of papillae
      during surgical treatment (open flap curettage) and will be examined by Immuno-histochemical
      analysis. Immune-staining will be done using p53 monoclonal mouse anti-human antibody.
    

Detailed description: 
      Background:

      The mechanisms responsible for gingival tissue damage are poorly understood, and both
      immune-mediated reactions and direct cytopathic effects of bacteria maybe involved. Based on
      direct effect of bacteria in cell cultures, it has been suggested that apoptosis might play
      an important role in periodontitis (Chen 1994).

      Programmed cell death (apoptosis) is normal physiologic process that contributes to
      maintaining tissue homeostasis. The process of apoptosis can be modulated by various stimuli
      hormones, cytokines, growth factors, infections and immune-responses (Renehan et al. 2001).

      Among other factors, the products of two genes that encode protein p53 and Bcl-2 have been
      shown to play fundamental regulatory role in apoptosis. P53 is the protein product of
      tumor-suppressor gene, and expression of P53 can induce apoptosis. This protein is also
      implicated in the regulation of tissue dynamics, and is specifically thought to induce
      apoptosis in terminally differentiated cells, including inflammatory cells (Bulut et
      al.2006).

      Fibroblast is a type of cell that synthesizes the extracellular and collagen in connective
      tissue. It plays a critical role in wound healing. Fibroblasts are the most common cells in
      connective tissue. The main function of fibroblasts is to maintain the structural integrity
      of connective tissue by continuously secreting precursors of extracellular matrix. it was
      reported that apoptosis levels increased in gingivitis and periodontitis (Jarenberg et al.
      2002).

      Cigarette smoking is a risk factor for many diseases, and recent evidence indicates that
      smoking adversely influences periodontal health. A number of epidemiologic studies have shown
      strong association between smoking and prevalence and severity of periodontitis (Bostrom et
      al. 1998). Whereas, the pathogenesis of periodontitis in smokers is poorly understood there
      are data suggesting that smoking effects on the periodontal tissues include defects in
      neutrophil function, impaired serum antibody responses to periodontal pathogens, and
      potentially diminished gingival fibroblast function (Shivanaikar et al. 2001). Smokers are
      considered a high-risk group for periodontitis, and smoking history is a useful clinical
      predictor of future disease activity (Hanokia et al. 2000).

      Aims of the study:

        -  Investigation of the effects of smoking on fibroblasts apoptosis in smokers with
           periodontitis compared to non-smokers with periodontitis using immuno-histochemical
           methods.

        -  Comparison of apoptosis levels of gingival fibroblasts between chronic and aggressive
           periodontitis.

      Materials and methods:

      A total of 80 subjects will be invited to participate in this study from the patients
      referred to the Department of Periodontology, Faculty of Dentistry, University of Damascus.
      The study will be approved by a specific Review Board. Subjects will be recruited according
      to specific inclusion criteria after completion of medical and dental history questionnaires.
      Patients will sign a consent form after being advised about the nature of the study.

      The selection of patients will be made according of the criteria approved by the 1999
      international world workshop for a classification system of periodontal diseases and
      conditions (Armitage 1999) using five clinical parameters and full mouth or panoramic
      radiographs for diagnosis.

      Subjects will be allocated into four groups:

        -  Smoking Chronic Periodontitis group (ChP-S): comprise 20 patients who are smokers and
           aged > 45 years and have presence of ≥2 non-adjacent sites per quadrant that were not
           first molars or incisors, with probing depth (PD) ≥5 mm, which bleed on gentle probing.
           The demonstrated radiographic bone loss ≥30% of the root length, patient with poor oral
           hygiene, the amount of accumulated plaque commensurate with the amount of clinical
           attachment level (CAL)

        -  Non-smoking Chronic periodontitis group (ChP-NS): comprise 20 age-sex matched patients
           who are non-smokers and have chronic periodontitis.

        -  Smoking Aggressive Periodontitis group (AgP-S): comprise 20 patients who are smokers and
           aged < 35 years and diagnosed with rapid attachment loss with periodontal pocket depth
           (PD) > 4 mm around at least three teeth other than the first molars and incisors. Rapid
           bone destruction (>50%bone loss at diseased sites). Weak relationship between dental
           plaque and the severity of gingival inflammation.

        -  Non-smoking Aggressive periodontitis group (AgP-NS): comprise 20 age- and sex matched
           patients who are non-smokers and have aggressive periodontitis.

      Clinical measurements:

      A standard periodontal probe will be used for recording periodontal indices at six sites per
      tooth. The examined clinical parameters include bleeding on probing (BOP), plaque index (PI),
      clinical attachment loss (CAL) and periodontal pocket depth (PPD) and gingival index (GI).

      Biopsy collection and analysis

        -  The biopsy samples will be obtained from patients during surgical treatment (open flap
           curettage) where biopsy is taken from the base area of papilla.

        -  Samples will be placed in 10% formalin.

        -  The samples will be then installed in paraffin wax.

        -  Samples will be analyzed in the by means of p53 monoclonal mouse anti-human antibody.
    

Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        A total of 80 subjects will be invited to participate in this study from the patients
        referred to the Department of Periodontology, Faculty of Dentistry, University of Damascus.
        Patients should have a diagnosis of periodontitis (either chronic or aggressive). Any
        candidate will be approached and informed about this clinical study with the relevant
        information sheet. Informed consent forms will be obtained.Using five clinical parameters
        and full mouth or panoramic radiographs, the participants will be allocated to four groups
        according to their condition as well as their smoking habit. The description of these
        groups has given before.
      
Keywords: apoptosis; periodontal disease; smoking