Treatment of intrabony defects with enamel matrix proteins or bioabsorbable membranes. A 4-year follow-up split-mouth study

BACKGROUND

Treatment with enamel matrix proteins (EMD) and guided tissue regeneration (GTR) with bioabsorbable membranes has been shown to promote periodontal regeneration; however, until now, there were only limited data on the long-term clinical results following these regenerative techniques. Therefore, the aim of the present study was to present the 4-year results following treatment of intrabony defects with EMD or guided tissue regeneration (GTR).

METHODS

Twelve patients, each displaying one pair of intrabony defects located contralaterally in the same jaw, were randomly treated with EMD or with GTR by means of bioabsorbable membranes. The following clinical parameters were evaluated at baseline, at 1 year, and at 4 years after treatment: plaque index (P1), gingival index (G1), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL). The primary outcome variable was CAL. No statistically significant differences between the groups were found at baseline. Power analysis to determine superiority of EMD treatment showed that the available sample size would yield 70% power to detect a 1 mm difference.

RESULTS

The sites treated with EMD demonstrated mean CAL change from 9.8 +/- 2.0 mm to 6.4 +/- 1.6 mm (P<0.001) and to 6.8 +/- 1.8 mm (P<0.001) at 1 and 4 years, respectively. No statistically significant differences were found between the CAL mean at 1 and 4 years postoperatively. The sites treated with GTR showed a mean CAL change from 9.8 +/- 2.3 mm to 6.6 +/- 1.7 mm (P<0.001) at 1 year and to 6.9 +/- 1.8 mm (P<0.001) at 4 years. The CAL change between I and 4 years did not present statistically significant differences. No statistically significant differences in any of the investigated parameters were observed at 1 and 4 years between the treatment groups.

CONCLUSIONS

It was concluded that the CAL gain obtained following treatment with EMD or GTR can be maintained over a 4-year period.

Effect of an enamel matrix protein derivative (Emdogain) on ex vivo dental plaque vitality

BACKGROUND

A common clinical observation following surgical periodontal therapy with an enamel matrix derivative (Emdogain) is the improved healing of the soft tissues and the limited inflammation of the operated areas. These clinical observations are empirical and difficult to explain. One of the factors influencing the early wound healing might be a potential antimicrobial effect of Emdogain.

AIM

To investigate the effect of Emdogain on the vitality of ex vivo supragingival dental plaque and to compare this effect to that of a standard 0.2% chlorhexidine solution.

MATERIALS AND METHODS

24 patients suffering from adult periodontitis were included in the study. At the beginning of the experiment, all participants were given a professional tooth cleaning. For the following 4 days, they had to refrain from any kind of oral hygiene measures. At day 5, from each of the volunteers, a voluminous plaque biofilm sample was taken with a sterile curette from the vestibular surfaces of the 1st lower molars and divided into 5 equal parts. Each part was mounted with 5 microl of the following solutions: (1) NaCl, (2) enamel matrix derivative dissolved in water (EMD), (3) enamel matrix derivative dissolved in the vehicle (Emdogain), (4) vehicle (propylene glycol alginate, PGA), (5) 0.2% chlorhexidine digluconate (CHX). After a reaction time of 2 min the test solutions were sucked off, and subsequently the biofilm was stained with a fluorescence dye. The vitality of the plaque flora after the treatments was evaluated under the fluorescence microscope (VF%).

RESULTS

Plaque samples treated with NaCl showed a mean vitality of 76.8+/-8%. The EMD, Emdogain, PGA and CHX showed VF values of 54.4+/-9.2, 21.4+/-10.6%, 19.6+/-11.6% and 32.3+/-11.8%, respectively. Emdogain, PGA and CHX showed statistically highly significant reductions (p<0.0001) in terms of bacteria vitality when compared to water (negative control) and EMD. Both Emdogain and PGA were found to be statistically significantly different compared to CHX (p<0.001) (positive control).

CONCLUSION

The results of this study indicate that Emdogain might have an antibacterial effect on the vitality of the ex vivo supragingival dental plaque flora.

Patterns of cytokeratin expression in monkey and human periodontium following regenerative and conventional periodontal surgery

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 microm. The sections were alternatively stained either with hematoxylin and eosin, or immunohistochemically by using one of the broad range monoclonal antibodies 34betaE 12 (for cytokeratins 1, 5, 10 and 14) or KL 1 (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 borderline between the regenerated cementum and the epithelial downgrowth. It was concluded that: a) the reformed junctional epithelium, following any type of surgical procedure, displays a similar pattern of cytokeratin expression to the original junctional epithelium; b) in the newly formed periodontal ligament, no expression of cytokeratins is present; and c) the epithelial rests of Malassez do not seem to reform after regenerative periodontal surgery.

The effect of postsurgical antibiotics on the healing of intrabony defects following treatment with enamel matrix proteins

BACKGROUND

Regenerative treatment with enamel matrix proteins has been shown to promote healing in intrabony defects. However, up to now various postoperative antibiotic regimens have been used in combination with enamel matrix proteins and therefore it cannot be excluded that the results may also be attributable to the effect of the antibiotic treatment. The aim of this randomized, controlled, blinded, clinical investigation was to determine the effect of postsurgical administration of antibiotics on the healing of intrabony periodontal defects treated with enamel matrix proteins.

METHODS

Thirty-four patients each of whom exhibited one deep intrabony defect were randomly treated with either enamel matrix proteins plus antibiotics (test: EMD + AB) or with enamel matrix proteins alone (control: EMD). The antibiotic regimen consisted of a combination of 3 x 375 mg amoxicillin and 3 x 250 mg metronidazole daily for 7 days. The following parameters were recorded at baseline and at 1 year by the same calibrated and blinded investigator: plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL). Power analysis to determine superiority of antibiotic treatment showed that the available sample size would yield 85% power to detect a 1 mm difference.

RESULTS

No statistically significant differences in any of the investigated parameters between the 2 groups were observed at baseline. No serious adverse events such as allergic reactions or abscesses after any of the treatments were observed during the entire study period. The results have shown that in the EMD + AB group the PD decreased from 9.1 +/- 1.5 mm to 4.5 +/- 1.1 mm (P<0.0001) and the CAL changed from 11.0 +/- 1.6 mm to 7.5 +/- 1.4 mm (P<0.0001). In the EMD group the PD decreased from 9.0 +/- 1.7 mm to 4.3 +/- 1.7 mm (P <0.0001) and the CAL changed from 10.6 +/- 1.6 mm to 7.3 +/- 1.5 mm (P <0.0001). There were no significant differences in any of the investigated parameters between the 2 groups.

CONCLUSIONS

It can be concluded that the systemic administration of amoxicillin and metronidazole adjacent to the use of EMD for the surgical treatment of intrabony periodontal defects does not produce statistically superior PD reduction and CAL gain when compared to treatment with EMD alone. Hence, the present results do not support the routine administration of amoxicillin and metronidazole following regenerative treatment with EMD.

Clinical and histologic evaluation of human intrabony defects treated with an enamel matrix protein derivative (Emdogain)

An enamel matrix protein derivative (Emdogain) has been recently shown to promote periodontal regeneration in experimentally created recession-type defects. However, only limited histologic data from human material are available concerning the healing of intrabony periodontal defects following treatment with Emdogain. The aim of the present study was therefore to present the clinical and histologic results following the application of Emdogain in intrabony defects. Two patients with marginal periodontitis and deep intrabony defects adjacent to teeth scheduled for extraction were treated with Emdogain. The postoperative healing phase was uneventful in both cases. At 6 months following treatment, newly formed cementum with inserting collagen fibers was found in both specimens. In one case, the new attachment formation was also accompanied by bone neoformation. The results of this human histologic study indicate that Emdogain possesses the potential to stimulate new connective tissue attachment formation in human intrabony defects.

Treatment of intrabony defects with guided tissue regeneration and enamel-matrix-proteins. An experimental study in monkeys

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 microm 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.

Clinical and antibacterial effect of tea tree oil--a pilot study

The aim of this clinical pilot study was to compare the effect of tea tree oil with the effect of water and chlorhexidine on supragingival plaque formation and vitality. Eight subjects were asked to refrain from any kind of mechanical oral hygiene for 4 days after professional tooth cleaning (day 0), and to rinse with water instead for 1 week, with chlorhexidine in a second and tea tree oil in a third test week. The plaque index (PI), which was evaluated daily (days 1-4), served as a clinical control parameter. On the last day of the study (day 4), the plaque covering the front teeth was stained, photographed, and therefrom the plaque area (PA; %) was estimated using a digital measuring system. Each day of the study (days 1-4), the sampled plaque was examined using a vital fluorescence technique. Tea tree oil reduced neither the clinical parameters (PI and PA) nor the vitality of the plaque flora significantly. Within the limitations of the study design, it was determined that a solution with tea tree oil--utilized as ordinary mouthwash--has no positive effect on the quantity or quality of supragingival plaque.

Healing of fenestration-type defects following treatment with guided tissue regeneration or enamel matrix proteins. An experimental study in monkeys

The aim of the present study was to evaluate histologically in monkeys the healing in acute fenestration-type defects following treatment with guided tissue regeneration (GTR) or enamel matrix proteins (EMD). Standardized "critical size" fenestration-type defects were produced surgically at the vestibular aspect of teeth 13, 23, 33, 43 in three monkeys (Macaca fascicularis). The vestibular bone plates were removed and the root surfaces were debrided by means of hand instruments in order to completely remove the root cementum. Following root conditioning with ethylenediaminetetraacetate (EDTA), the defects were treated using one of the following therapies: (1) GTR, (2) EMD, or (3) control (coronally repositioned flaps). After 5 months the animals were killed 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. Eight-micrometer-thick step serial histological sections were cut in a vestibulo-oral direction, stained with hematoxylin and eosin or oxone-aldehyde-fuchsin-Halmi, and subsequently examined under the light microscope. The results showed that, in the defects treated with GTR, a new connective tissue attachment (i.e., new cementum with inserting collagen fibers) and new bone formation had consistently occurred, whereas, in the defects treated with EMD or with coronally repositioned flaps, new attachment and new bone reformed to a varying extent. The quality of the cementum did not differ after EMD, GTR, or flap surgery. It was concluded that GTR treatment with bioresorbable membranes seems to predictably promote new attachment and new bone formation, whereas the application of EDTA or EMD may also enhance periodontal healing to a certain extent. Further studies with higher numbers of animals and defects are needed in order to definitely clarify the effect of root surface conditioning with EDTA and EMD on periodontal healing.

GTR with bioresorbable membranes in the treatment of intrabony defects: a clinical and histologic study

The aim of the present study was to evaluate clinically and histologically the treatment of intrabony periodontal defects with a bioresorbable membrane barrier. Fifty-two intrabony periodontal defects were treated according to the principles of guided tissue regeneration (GTR) with a bioresorbable membrane. Results were evaluated by assessing probing pocket depth, recession of the gingival margin, and clinical attachment level at baseline and at 1 and 2 years after therapy. Bone level changes were evaluated radiographically. The postoperative phase was uneventful in all cases. There was a mean probing pocket depth reduction from 8.4 to 3.6 mm, a mean increase of gingival margin recession from 1.5 to 3.0 mm, and a mean clinical attachment level change from 9.9 to 6.5 mm. Mean attachment gain was 3.4 mm. Two teeth scheduled for extraction were also treated with the same bioresorbable membrane. The histologic analysis 6 months after treatment revealed the formation of new connective tissue attachment and new alveolar bone in both cases. Based on the histologic findings it can be concluded that the clinical improvements following GTR with this type of bioresorbable membrane may represent, at least in part, true periodontal regeneration.

Healing of human intrabony defects following treatment with enamel matrix proteins or guided tissue regeneration

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.

Presence of oxytalan fibers in human regenerated periodontal ligament

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-microm 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 cementum on the root surface. It is concluded that oxytalan fibers are formed de novo in human regenerated periodontal ligament tissue.

Comparison of enamel matrix proteins and bioabsorbable membranes in the treatment of intrabony periodontal defects. A split-mouth study

BACKGROUND

Enamel matrix proteins (EMP) have recently been introduced as a new modality for regenerative periodontal treatment. However, limited information is available concerning the comparison of the treatment of intrabony periodontal defects with enamel matrix proteins and other regenerative treatment alternatives.

METHODS

The aim of the present controlled clinical trial was to compare the treatment of deep intrabony periodontal defects with EMP to that with guided tissue regeneration (GTR) with bioabsorbable membranes. Sixteen patients, each of whom displayed one pair of intrabony defects located contralaterally in the same jaw, were randomly treated with EMP or with a bioabsorbable membrane. Prior to surgery and 8 months later the following parameters were evaluated by a blinded examiner: Plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL). Antibiotics (amoxicillin and metronidazole) were given during the first 10 days after surgery. No statistical significant differences in any of the investigated parameters between the 2 groups were observed at baseline.

RESULTS

No serious adverse events (e.g., allergic reactions or abscesses) after any of the treatments were noted during the entire observation period. Membrane exposure occurred in 7 out of the 16 GTR treated sites. Clinical examination was performed again 8 months postoperatively. Sites treated with EMP demonstrated a reduction of PD from 8.1+/-1.7 mm to 4.3+/-1.2 mm (P <0.001) and a change in CAL from 10.3+/-1.8 mm to 7.2+/-1.2 mm (P <0.001). The sites treated with GTR showed a reduction of PD from 8.3+/-1.7 mm to 4.3+/-0.7 mm (P <0.001) and a change of CAL from 10.1+/-1.9 mm to 7.1+/-1.7 mm (P <0.001). Both treatment procedures led to significant improvements of PD and CAL. However, no statistically significant differences in any of the investigated parameters were observed between the test and control group.

CONCLUSIONS

It may be concluded that both therapies led to shortterm improvements of the investigated clinical parameters. Further studies of much higher power are needed to support equivalence.

Regeneration of oxytalan fibres in different types of periodontal defects: a histological study in monkeys

The aim of the present study was to investigate in monkeys the regrowth of oxytalan fibres in different types of acute and chronic periodontal defects following regenerative periodontal treatment. One-wall intrabony and mandibular furcation III-defects were produced surgically in 3 monkeys (Macaca fascicularis). After a 6-wk dental plaque accumulation period the defects were exposed using a full thickness flap procedure. The granulation tissue was removed and the root surfaces were scaled and planed. Additionally, fenestration-type defects were produced at the vestibular surfaces of the maxillary and mandibular canines by surgically removing the vestibular bone plates and the root cementum. Subsequently, the defects were treated with guided tissue regeneration (GTR), enamel matrix proteins (EMP), combination of EMP and GTR or with coronally repositioned flaps. The postoperative care included tooth cleaning once a week during the experiment. After 5 months the animals were sacrificed and and the block sections were embedded in paraffin. Eight microns histological sections were cut and stained with the oxone-aldehyde-fuchsin-Halmi method. The results revealed that in all specimens where a regenerated periodontal ligament could be observed newly formed oxytalan fibers were present. They had a mainly apico-occlusal orientation and were localized closer to the cementum than to the alveolar bone. The regenerated oxytalan fibers had a similar morphological appearance than those observed in the original periodontal ligament regardless of the treatment modality by which regeneration was accomplished. Their presence was related to that of newly formed cementum suggesting a strong relationship between these 2 tissues. The neoformation of oxytalan fibres can thus be observed in some types of periodontal defects where the cementum and the periodontal ligament have been regenerated.