|University of Medicine and Pharmacy Tîrgu Mureş
Abstract of the PhD thesis
Clinical and immunohistochemical studies in dental inclusion
Phd Candidate Coşarcă Adina-Simona
Scientific coordinator:Păcurar Mariana
Keywords: dental inclusion, surgical-orthodontic treatment,immunohistochemistry,dental follicle
Dental impaction (dental inclusion) is defined as the intraosseous retention of a completely developed tooth, or as the failure of tooth eruption in its appropriate site, within the dental arch, during its normal period of eruption (deep impaction). The teeth that are most commonly impacted are the mandibular third molars, followed by upper canines. An impacted tooth also retains the follicular sac which consists of condensed mesenchymal tissue that sometimes contains epithelial islands arising from the process of odontogenesis and often it is covered by small amounts of odontogenic epithelium. These epithelial cells can maintain the ability of proliferation and differentiation, and may be the starting point of a dental pathology associated with impaction or cystic tumor pathology (follicular cyst, keratocyst, ameloblastoma). Various immunohistochemical markers have been studied to assess the proliferating ability of the residual epithelium.
The thesis contains two parts.The general part of the thesis presents the current state of the dental impaction and some general information regarding immunohistochemistry( diagnosis,treatment,etiology, immunohistochemical markers). The personal part of the thesis contains a clinical and statistical study on canine and third molar impaction performed in patients exhibiting dental impaction, that were referred and treated at the Oral and Maxillo-Facial Surgery Clinic of Tîrgu Mureș in the 2009–2012 period, investigating several different parameters.
By reviewing clinical records, we were able to establish whether the patient was referred by a specialist (orthodontist, dentist, general physician), or presented spontaneously. Finally, we analyzed the surgical protocols and the type of treatment applied to each patient (combined surgical-orthodontic or odontectomy).
We analyzed the immunoexpression of the Ki67, p53 PCNA, and MCM3 in epithelial residues from dental follicles of impacted teeth in order to assess their proliferative capacity, as well as their cystic transformation potential. Our objective was also to identify a possible correlation between the immunoexpression of the studied markers in developmental odontogenic cysts (DOC) and keratocystic odontogenic tumor (KCOT) so as to evaluate their evolutionary behavior.
In the last chapter our aim was to compare the periodontal status of impacted canines after 5 years following completion of the combined surgical and orthodontic treatment. The results were compared with data from the literature.
The final conclusions are the following:
Canine impaction is the second-most frequent impacted tooth within the dental arch, after the third molars.
Ki67 and PCNA are the most useful markers to determine the proliferative capacity of epithelial residues from the dental follicle.
The results of our study confirm the aggressive character of keratocystic odontogenic tumors and that certain inflammation factors have positive influences on the proliferative ability of the odontogenic epithelium in the developmental odontogenic cysts.
Using gingivectomy as surgical exposure technique should be carefully evaluated in the preoperative stage, considering its aesthetic complications that may follow after the surgical and orthodontic treatment.
Probing depth and gingival recession should be monitored throughout the surgical and orthodontic treatment and also after completing the therapy, as these parameters may be essential signs of a periodontal disease in the area of the treated teeth.