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Notes: Background: The use of enamel matrix proteins (EMD) has been recently introduced as a new treatment alternative for periodontal regeneration. However, no histological studies are available investigating the effect of EMD in the treatment of degree III furcation involvements.Objectives: The aim of this study was to evaluate the healing of mandibular degree III furcation involvements histologically following treatment with guided tissue regeneration (GTR), EMD and a combination of EMD and GTR.Material and Methods: Degree III furcation involvements were surgically created at the teeth 36, 37, 46, 47 in three monkeys (Macaca fascicularis). Spontaneous healing of the defects was prevented by placing impression material into the defects. After 6 weeks, full-thickness flaps were elevated at the buccal and lingual aspect of the experimental teeth. Following removal of all granulation tissue from the furcation defects, scaling/root planing and conditioning of the root surfaces with 24% EDTA gel, the defects were treated with one of the following treatment modalities: (i) EMD, (ii) GTR or (iii) a combination of EMD and GTR. The defects serving as control did not receive any treatment, except from complete coverage with coronally displaced flaps. After 5 months of healing, the animals were killed and perfused with 10% buffered formalin for fixation. The experimental teeth with surrounding tissues were dissected free, decalcified in EDTA, dehydrated and embedded in paraffin. 8 μm thick histological sections were cut and stained and subsequently examined under the light microscope.Results: The histological analysis revealed that with GTR or combined EMD and GTR treatment, new attachment formation (new cementum with inserting collagen fibers) had occurred on almost the entire circumference of the furcation and new bone was almost filling the defect in the situations where the membrane was not exposed. The sites treated only with EMD exhibited new attachment and new bone formation to a varying extent, while the control sites presented only limited new attachment and bone formation.Conclusion: The results provided histological evidence suggesting that both GTR and EMD may result in true periodontal regeneration, and suggest that this type of healing might be favored by such treatments in comparison with flap surgery.

Notes: Background: Enamel matrix proteins (EMD) have recently been introduced in regenerative periodontal treatment. However, no histological data are yet available concerning the effect of treating intrabony periodontal defects with EMD, and no histological comparisons have been made comparing the result of treatment of intrabony defects with EMD with that of the treatment with guided tissue regeneration (GTR).Aim: Therefore, the aim of the present study was to evaluate histologically in monkeys the effect of treating intrabony defects with EMD, GTR or combined EMD and GTR.Method: Intrabony periodontal defects were produced surgically at the distal aspect of teeth 14, 11, 21, 24, 34, 31, 41 and 44 in 3 monkeys (Macaca fascicularis). In order to prevent spontaneous healing and to enhance plaque accumulation metal strips were placed into the defects. After 6 weeks the defects were exposed using a full-thickness flap procedure. The granulation tissue was removed and the root surfaces were debrided by means of hand instruments. Subsequently, the defects were treated using one of the following therapies: (i) GTR, (ii) EMD, or (iii) combination of EMD and GTR. The control defects were treated with coronally repositioned flaps. After 5 months, the animals were sacrificed and perfused with 10% buffered formalin for fixation. Specimens containing the defects and surrounding tissues were dissected free, decalcified in EDTA and embedded in paraffin. 8 μm thick histological sections were cut and stained and subsequently examined under the light microscope.Results: In the control specimens, the healing was characterized by a long junctional epithelium and limited periodontal regeneration (i.e., new periodontal ligament, new cementum with inserting connective tissue fibers and new bone) in the bottom of the defect. The GTR-treated defects consistently presented periodontal regeneration when the membranes were not exposed whereas the sites treated only with EMD presented regeneration to a varying extent. The combined therapy did not seem to improve the results.Conclusion: It can be concluded that all 3 treatment modalities favor periodontal regeneration.

Notes: Abstract. The aim of the present study was to investigate whether oxytalan fibers are formed in the regenerated human periodontal ligament. 6 patients, each of them exhibiting an advanced intrabony defect, were treated with a bioresorbable membrane according to the GTR-principle. Following a healing period of 6 months, the teeth were extracted together with their surrounding soft and hard tissues and subsequently fixed in 10% buffered formalin. Following decalcification in EDTA, the specimens were embedded in paraffin and 8-μm histological sections were cut in the mesio-distal direction, parallel to the long axes of the teeth. The sections were stained with hematoxylin and eosin, or with the oxone-aldehyde-fuchsin-Halmi staining method and examined in the light microscope. A regenerated periodontal ligament containing newly-formed oxytalan fibers was observed in all specimens. Many of them inserted into the newly formed cementumon the root surface. It is concluded that oxytalan fibers are formed de novo in human regenerated periodontal ligament tissue.

Notes: The aim of the present study was to evaluate histologically in humans the healing of advanced intrabony defects following treatment with enamel matrix proteins (EMD) or guided tissue regeneration (GTR). Fourteen patients, each of them displaying 1 advanced intrabony defect around teeth scheduled for extraction were included in the study. The defects were treated randomly either with an enamel matrix protein derivative (Emdogain ®, BIORA AB, Malmö, Sweden) or with a bioabsorbable membrane (Resolut®, Regenerative Material. W.L. Gore & Assoc, Flagstaff, Arizona, USA). At baseline the mean probing pocket depth (PPD) in the EMD group was 11.3 ± 1.8 mm and the mean clinical attachment level (CAL) 12.1 ± 2.0 mm. whereas in the GTR group the mean PPD was 11.4 ± 2.2 mm and the mean CAL 13.3 ± 2.3 mm. Healing was uneventful in all cases. Neither allergic reactions against EMD or the bioabsorbable membrane. nor suppuration or abscesses were observed. The clinical results revealed at 6 months in the EMD group a mean PPD of 5.6 ± 1.3 mm and a mean CAL of 9.1 ± 1.5 mm. In the GTR group the mean PPD was 5.6 ± 1.3 mm and the mean CAL 10.1 ± 1.5 mm. The histological analysis showed in the EMD group a mean 2.6 ± 1.0 mm of new attachment (i.e. new cementum with inserting collagen fibers) and a mean 0.9 ± 1.0 mm of new bone. In this group, the formation of new attachment was not always followed by bone regeneration. In the GTR group, the mean new attachment was 2.4 ± 1.0 mm and the mean new bone 2.1 ± 1.0 mm. In every case treated with GTR, the formation of new attachment was followed by a varying amount of new bone. After both types of regenerative treatment the newly formed cementum displayed a predominantly cellular character. The findings of the present study indicate that the treatment of intrabony defects with enamel matrix proteins or with bioabsorbable membranes enhances the formation of a new connective tissue attachment in humans.

Notes: The pattern of cytokeratin expression has been extensively described in the normal and inflamed periodontium. However, there is no information regarding the pattern of cytokeratin expression in the periodontium which has been reformed following regenerative periodontal surgery. The aim of the present investigation was to evaluate the pattern of cytokeratin expression in the reformed human and monkey periodontium following regenerative and conventional periodontal surgery. In 3 monkeys, acute fenestration-type and chronic intrabony defects were treated with guided tissue regeneration (GTR), enamel matrix proteins (EMD), or coronally repositioned flap surgery (control). After a healing period of 5 months, the animals were sacrificed and perfused with 10% buffered formalin for fixation. Specimens containing the defects and surrounding tissues were dissected free, decalcified in EDTA and embedded in paraffin. Histological sections were cut with the microtome set at 3 μm. The sections were alternatively stained either with hematoxylin and eosin, or immunohistochemically by using one of the broad range monoclonal antibodies 34βE12 (for cytokeratins 1, 5, 10 and 14) or KL1 (for cytokeratins 1, 2, 5, 6, 7, 8, 10, 11, 16 and 19), or one of the individual monoclonal antibodies LL025 (for cytokeratin 16), DC 10 (for cytokeratin 18), A53-B/A2 (for cytokeratin 19). Twelve patients, each displaying one deep intrabony defect scheduled for extraction due to advanced periodontitis or prosthetic reasons, were treated as described above. Following a healing period of 6 months, the teeth were extracted together with some of their surrounding soft and hard tissues. The histological and immunohistochemical processing of the human biopsies was identical to that described in monkeys. The results revealed that both the normal non-treated (original) monkey and human junctional epithelium stained strongly with all of the monoclonal antibodies used. The reformed junctional epithelium displayed the same cytokeratin expression pattern as the non-treated junctional epithelium. No differences regarding the cytokeratin expression pattern of the junctional epithelium were found between the treatments and types of healing (i.e. regenerative, through a new periodontal ligament, or reparative through a long junctional epithelium). In the intact periodontal ligament, the epithelial rests of Malassez displayed a comparable cytokeratin expression pattern to that of the junctional epithelium. However, no expression of cytokeratins was seen in the newly formed periodontal ligament. In such specimens, cytokeratin expression was observed only until the