The Influence of Liners on the Pulp Inflammation.

INTRODUCTION: The study included application of liners and dental composites in to cavities of six experimental animals-rabbits (Oryctolagus cuniculus). OBJECTIVE The aim of the study was to investigate rabbit dental pulp response to different liners. Methods Cavity preparation for class V were made on the maxillary central incisors and one lower incisor, while the second lower incisor served as a control tooth. These teeth were restored with the use of one of the following liners--Calcimol LC, ANA Liner and Fuji II LC Improved, and Ceram-X mono dental composite. After an observation period of five days animals were sacrificed and prepared for histological analysis.The existence and degree of the pulp inflammation was determined by using a light microscope. RESULTS: Results showed that the used liners do not cause distortion of the structure and continuity of the odontoblastic layer. Inflammation was not registered in the control group, while in each group of tested materials one tooth with mild signs of hyperemia was registered. Results showed that all three tested liners demonstrated favorable effects on the pulp of the tooth and did not lead to inflammatory reactions. CONCLUSION: Histological analysis of the dental pulp of experimental animals suggests that the liners used in this study do not compromise the integrity of the odontoblastic layer, if it is applied over a thin layer of dentin. In each group of tested materials one tooth with mild signs of hyperemia and vasodilation was registered.

Changes in subgingival microflora after placement and removal of fixed orthodontic appliances.

INTRODUCTION: The placement of fixed orthodontic appliances may lead to increased plaque accumulation and changes in subgingival microflora. OBJECTIVE: The aim of this study was to examine the changes in frequency of subgingival microflora that occur after placement and removal of fixed orthodontic appliance using polymerase chain reaction (PCR). METHODS: This study included 33 orthodontic patients, who were divided into two groups. Subgingival plaque samples were collected from the right upper incisor (U1) and right upper first molar (U6). In group A, the samples were taken three times: before placement appliance (T1), after one month (T2), and after 3 months (T3). In group B the samples were also taken three times: before appliance removal (T1), after one month (T2), and after three months (T3). PCR method was used to determine the presence of P. gingivalis, A. actinomycetemcomitans, T. forsythia, and P. intermedia. RESULTS: In group A the frequency of P. gingivalis showed statistically significant decrease at U1 (p = 0.049) and U6 (p = 0.008), from T1 to T2, and at U1 (p = 0.048) from T1 to T3. In group B only the frequency of T. forsythia showed a statistically significant decrease, at U6 (T1 vs.T2, p = 0.004; T1 vs.T3, p = 0.0003). Regarding other analyzed bacteria, changes in the presence were noticed but no statistical significance was found. CONCLUSION: Placement of fixed appliances may have an impact on subgingival microflora, but in the first months after the placement and removal of the appliance changes were not significant, probably due to good oral hygiene.