Evaluation of doxycycline hyclate gel and chlorhexidine gel as root conditioners on healthy root surface: a comparative scanning electron microscopic study

Since critical events in periodontal regeneration involve cementogenesis and the attachment of new connective tissue to the root surface, a considerable amount of research has been aimed at evaluating whether chemical agents can transform the root surface to a biologically suitable one. A number of agents have been used including tetracycline, citric acid, EDTA gel, phosphoric acid, fibronectin, enamel matrix proteins and growth factors. The purpose of the present study was to evaluate and compare by scanning electron microscope [SEM] the surface changes of human root dentin on topical application of doxycycline hyclate gel and chlorhexidine gel. A total of 26 dentin specimens were used in the present study. They were divided into three groups. The first group comprised 10 specimens conditioned with doxycycline hyclate gel. The second group also comprised 10 specimens conditioned with chlorhexidine gel. The third group comprised 6 specimens used as controls. The specimens in group I and II were burnished for 3 minutes with the two gels. Immediately following treatment procedures, the specimens were rinsed, dehydrated and prepared for SEM. Measurements of the width of 10 randomly selected dentinal tubules orifices were done in the control and each of the conditioned groups. The results of the present study indicate that doxycycline hyclate causes a great degree of morphologic alteration in root dentin. This was reflected by the presence of a large number of patent dentinal tubules in the studied specimens. The difference in tubule diameter between the doxycycline group and control group was statistically significant and insignificant between the doxycycline group and chlorhexidine group, in spite of the greater number of wide tubules and the higher mean diameter of tubules in doxycycline group. Removal of smear layer was demonstrated in several areas while present in few areas in both studied groups

comparative histologic analysis of the use of a resorbable collagen membrane and enamel matrix derivative in the management of dehiscence type defects

Several studies have documented the clinical efficiency of guided tissue regeneration [GTR] with resorbable collagen membranes and enamel matrix derivative [EMD] in periodontal regenerative therapy. The objective of this controlled experimental study was to compare the healing process of dehiscence type critical sized defects treated by EMD, or GTR. Eight mongrel dogs were used. Buccal osseous dehiscences were surgically created on the roots of maxillary canines, bilaterally. The defects were randomly assigned to one of the treatments: root conditioning and EMD application, or GTR with bioabsorbable Biomend Extend [Trade Mark] collagen membrane. During the follow up period, all animals showed uneventful healing with no serious adverse reactions. The dogs were sacrificed at 1 and 3 months post surgically, and the blocks were processed. Qualitative assessment of tissue health and reaction, periodontal regeneration and integrity of implanted materials was carried out. Both treatment modalities resulted in true periodontal regeneration in the form of new cementum, periodontal ligament and alveolar bone formation in the created defects. Moreover, EMD treated sites revealed both acellular and cellular cementum deposition, whereas GTR therapy resulted mainly in cellular cementum formation. Regarding the new alveolar bone formation, EMD group revealed superior results. Concerning tissue reaction, more inflammatory cells were observed in GTR group, probably related to membrane disintegration. Within the limits of this study, it can be concluded that EMD and Biomend Extend [Trade Mark] membrane are almost equally effective in producing true periodontal regeneration in periodontal dehiscence type defects, with EMD demonstrating slightly better clinical healing and superior histologic results

Histological and histochemical evaluation of furcal perforation repair in dogs using mineral trioxide aggregate [MTA] mixed with water based lubricant

Furcation perforation offers a great challenge to the dentist and causes poor prognosis of affected teeth. Mineral trioxide aggregate [MTA] is a multipurpose material, that has many uses, such as root end filling, pulp capping, and perforation repair. The present study was conducted to evaluate histologically and histochemically the effect of a new MTA formulation when mixed with Surgilube gel[registered sign] on repair of furcation perforation. Eight dogs were included in this study. Access cavities were performed in mandibular premolars. One side of the mandible was used as experimental group, where the furcation perforations in four premolars were immediately sealed with a mixture of MTA and Surgilube gel. In the other side of the mandible, two premolars were used as positive controls where perforations were left unsealed, whereas the other two premolars were negative controls left intact without perforation. Clinical examination was performed at baseline and before euthanizing the animals. Four dogs were sacrificed after one month, whereas the remaining were killed after four months. Histological evaluation was done using H and E and Trichrome stains, as well as histochemical examination for detection of alkaline phosphatase [ALP] enzyme activity. Negative controls showed normal healing clinically with neither pocket formation nor radiographic bone loss. This was confirmed histologically and histochemically. As for the MTA group, the same clinical findings were observed. Histologic evaluation at one month revealed mild inflammation, and appearance of early signs of regeneration including formation of new cementum and alveolar bone. Tissue maturation and calcification were evident at four months in this group with disappearance of inflammatory reaction. The perforations were sealed with periodontal attachment apparatus reformed at that site. Concerning unsealed perforations, they were associated with pocket formation. Histologically, they showed at one month severe inflammatory reaction with formation of fibrous tissue, whereas at four months, inflammation was still persisting with incomplete healing evidenced by fibrous tissue, irregular woven bone and small amount of new cementum. Histochemical evaluation revealed more intense reaction of ALP activity in MTA group, that was decreased at four months compared to one month as an indication of tissue mineralization. According to this study, MTA mixed with Surgilube gel is an excellent repair material for furcation perforations that has the potential of periodontal regeneration