Root Surface Conditioning Research Articles

Effect of EDTA Root Conditioning on the Healing of Intrabony Defects Treated With an Enamel Matrix Protein Derivative

Regenerative periodontal therapy with an enamel matrix protein derivative (EMD) has been shown to promote regeneration in intrabony periodontal defects. However, in most clinical studies, root surface conditioning with EDTA was performed in conjunction with the application of EMD, and, therefore, it cannot be excluded that the results may also be attributable to the effect of the root conditioning procedure. The purpose of this study was to determine the effect of root conditioning on the healing of intrabony defects treated with EMD. Twenty-four patients, each of whom exhibited one deep intrabony defect, were randomly treated with either open flap debridement (OFD) followed by root surface conditioning with EDTA and application of EMD (OFD+EDTA+EMD) or with OFD and application of EMD only (OFD+EMD). The following parameters were recorded at baseline and at 1 year: plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), and clinical attachment level (CAL). No differences in any of the investigated parameters were observed at baseline between the two groups. Healing was uneventful in all patients. At 1 year after therapy, the OFD+EDTA+EMD group showed a reduction in mean PD from 9.3+/-1.3 mm to 4.0+/-0.9 mm (P<0.001), and mean CAL changed from 10.8+/-2.2 mm to 7.1+/-2.8 mm (P<0.001). In the OFD+EMD group, mean PD was reduced from 9.3+/-1.2 mm to 4.2+/-0.9 mm (P<0.001), and a change in mean CAL from 11.0+/-1.7 mm to 7.3+/-1.6 mm (P<0.001). There were no significant differences in any of the investigated parameters between the two groups. In intrabony defects, regenerative surgery including OFD+EDTA+EMD failed to show statistically significant differences in terms of PD reduction and CAL gain compared to treatment with OFD+EMD.

Root surface conditioning with nicotine or cotinine reduces viability and density of fibroblasts in vitro

The purpose of study was to evaluate fibroblast attachment and cellular morphology on root surfaces chemically conditioned with nicotine or cotinine. A secondary objective was to determine if mechanical scaling and root planning of these chemically conditioned surfaces would alter cellular attachment. Root surface dentin specimens were prepared from uniradicular teeth of non-smoking patients. Specimens were randomly assigned to two experimental groups: no treatment (chemical conditioning only) and scaling and root planning after conditioning (SRPC). The concentrations of the tested substances were in the range of 0-1 mg/mL (nicotine) and 0-1 g/mL (cotinine). After a 24-h conditioning period, dentin slices were incubated with continuous lineage of fibroblastic cells from rat (McCoy cells) for another 24 h. Specimens were prepared for SEM analysis and microphotographs. The statistical analysis of the data indicated significant alteration of cellular morphology on fibroblasts that were grown on root surface exposed to nicotine concentrations greater than 1 ?g/mL. This effect of nicotine was not reduced by SRPC. On the other hand, in the SRPC group cellular density was greater. For cotinine-conditioned specimens, the greater concentrations also led to alteration on morphology, and these alterations were observed in the SRPC group as well. Cotinine did not induce significant changes on cellular density. The results indicated that fibroblasts are negatively influenced by nicotine present on the dentin substrate and also that scaling may reduce these effects. Cotinine treatment on root surfaces may alter cell morphology and density but these effects were less severe than that promoted by nicotine, and were not affected by scaling.

Healing of periodontal defects treated with enamel matrix proteins and root surface conditioning—an experimental study in dogs

Application of enamel matrix proteins has been introduced as an alternative method for periodontal regenerative therapy. It is claimed that this approach provides periodontal regeneration by a biological approach, i.e. creating a matrix on the root surfaces that promotes cementum, periodontal ligament (PDL) and alveolar bone regeneration, thus mimicking the events occurring during tooth development. Although there have been numerous in vitro and in vivo studies demonstrating periodontal regeneration, acellular cementum formation and clinical outcomes via enamel matrix proteins usage, their effects on the healing pattern of soft and hard periodontal tissues are not well-established and compared with root conditioning alone. In the present study, the effects of Emdogain ® (Biora, Malmö, Sweden), an enamel matrix derivative mainly composed of enamel matrix proteins (test), on periodontal wound healing were evaluated and compared with root surface conditioning (performed with 36% orthophosphoric acid) alone (control) histopathologically and histomorphometrically by means of the soft and hard tissue profile of periodontium. An experimental periodontitis model performed at premolar teeth of four dogs were used in the study and the healing pattern of periodontal tissues was evaluated at days 7, 14, 21, 28 (one dog at each day), respectively. At day 7, soft tissue attachment evaluated by means of connective tissue and/or epithelial attachment to the root surfaces revealed higher connective tissue attachment rate in the test group and the amount of new connective tissue proliferation in the test group was significantly greater than the control group ( p<0.01). New bone formation by osteoconduction initiated at day 14 in the test and control group. At day 21, the orientation of supra-alveolar and PDL fibers established, and new cementum formation observed in both groups. At day 28, although regenerated cementum was cellular in all of the roots in the control samples, an acellular type of cementum (1.32±0.83 mm in length and 3.16±0.23 μm in width) was also noted in six roots of test samples with an inconsistent distribution on the root surfaces. The amount of new cementum was significantly higher in the test group than the control group samples ( p<0.01). The width of the cellular cementum in the control group was more than the cellular cementum in the test group, but the difference was not statistically significant ( p>0.05). A firm attachment of acellular cementum to the root dentin with functional organization of its collagen fibers was noted, and, the accumulation and organization of cellular cementum in the control group was more irregular than the cellular cementum formed in the test group. The amount of new bone was 2.41±0.75 mm in the test and 1.09±0.46 mm in the control group at day 28. The rate of bone maturation (the number of osteons) was found higher in the test group (10.75±0.85) than the control group (5.50±0.86). Under the limitations of the study, our results reveal that when compared with root surface conditioning, enamel matrix proteins have more capacity for stimulating periodontal regeneration via their positive effects on root surfaces, i.e. inhibition of gingival epithelium down growth and stimulation of connective tissue proliferation and attachment to the root surfaces during wound healing. An acellular type of cementum regeneration and new alveolar bone formation by an accelerated osteoconductive mechanism are also achieved with application of enamel matrix proteins.

Bone morphogenetic protein-2 stimulates cell recruitment and cementogenesis during early wound healing.

The unique action of bone morphogenetic proteins (BMPs) on mineralised tissue formation indicates that BMPs are good candidates for use in stimulating periodontal regeneration. Relatively little is known about the mechanisms of actions of BMPs during periodontal regeneration, although recent evidence from our laboratory suggests that the effects of BMPs may be profoundly influenced by various factors including root surface conditioning, delivery systems and masticatory forces. The aim of this study was to investigate the effect of rhBMP-2 on cell recruitment during periodontal regeneration using a pulse-chase technique where cells are labelled with a thymidine analogue (BrdU) (pulse) and the migration of their progeny is followed (chase) during early wound healing. The relationship between the rhBMP-2 influence on cell recruitment from the periodontal ligament (PDL) and its ability to stimulate cementogenesis was also evaluated. The buccal aspect of the distal root of the first molar was denuded of its PDL, cementum and superficial dentine through a bony window created in the mandible of 64 Wistar rats under general anaesthesia. Test animals were treated with 10 microL of 500 microg/ml rhBMP-2 in a collagen membrane sponge (n=32) and control defects received 10 microl of saline in a collagen sponge (n=32). All animals received an intraperitoneal single pulse injection of 40 mg/kg BrdU label 2 days postoperatively. Groups of test and control animals (n=8) were killed 2 hours later on day 2 and at 4, 7 and 10 days postoperatively. Mandibles were processed for histological examination. The results show that rhBMP-2 had a profound effect on proliferation and migration of cells in the adjacent and deeper aspects of the PDL at 7 and 10 days post periodontal wounding (p<0.05). Significantly greater new cementum formation occurred in the test group at 10 days (p=0.03). This study shows that following periodontal wounding rhBMP-2 stimulates cell recruitment by increasing proliferation and migration of cells from the adjacent unwounded PDL into the wounded area, thus promoting periodontal regeneration by increasing new cementum formation.

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.

COMBINING RECONSTRUCTIVE AND REGENERATIVE THERAPIES

The authors used combined reconstructive and regenerative therapy to treat a patient who had a surgically created osseous defect that also was associated with a perforated root canal. The defect involved a maxillary canine that exhibited 10 millimeters of attachment loss on its mesial surface. Tetracycline root surface conditioning, glass ionomer cement, a decalcified freeze-dried bone allograft and an expanded-polytetrafluorethylene membrane were used to achieve a 7- to 8-mm gain in clinical attachment level two years after the initial surgery. This case illustrates the use of glass ionomer cement, in conjunction with regenerative therapy, to effectively treat a root perforation adjacent to a periodontal osseous defect.

Does root surface conditioning with citric acid delay healing?

Effects of topical citric acid application on tissue maturation was studied in standardized periodontal defects in 6 beagle dogs. Following elevation of facial mucoperiosteal flaps, fenestration defects, 3 mm in diameter, were made through the cortical bone and recessed 0.5 mm into the dentin of maxillary canines. 1 defect in each dog was conditioned with a saturated solution of citric acid for 3 min and then rinsed with saline. Control defects in contralateral teeth were treated with saline only for the same length of time. The defects were covered with an expanded polytetrafluoroethylene membrane and the flaps repositioned and sutured. 14 days postsurgery, healing appeared more advanced along the defect walls and floor than in the center of the defect in all instances. Histometrically, citric acid-conditioned defects exhibited a higher density of collagen fibers along the defect walls and floor and adjacent to the barrier membrane as well as more advanced resolution of the residual blood clot than the surgical controls. Differences in fibroblast density within specimen pairs were non-significant. All control defects but none of the acid-conditioned defects showed an artifactual split between the dentin walls and the granulation tissue. This study failed to support the contention that topical application of citric acid to root surfaces may delay healing following periodontal surgery.

Healing of the intrabony periodontal lesion following root conditioning with citric acid and wound closure including an expanded PTFE membrane.

The effect of citric acid conditioning of the root surface in conjunction with gingival flap surgery including barrier membranes (expanded polytetrafluoroethylene) was clinically evaluated in 26 intrabony periodontal defects in 23 patients. Control treatment included gingival flap surgery with barrier membranes alone. Twelve defects were treated with the experimental and 14 with the control protocol. Healing was evaluated 12 months after surgery. Initial probing depths approximated 6.9 mm and defect depths measured during surgery exceeded 4 mm. The patients exhibited good oral hygiene over the study interval as substantiated by low plaque and bleeding scores. Acid conditioning of the root surface did not enhance periodontal healing in this study, similar amounts of defect resolution were observed following either treatment protocol. Probing depth reduction generally approximated 1.8 mm; gain of clinical attachment, 0.8 mm; and defect bone fill, 1.2 mm. Under the prevailing conditions, the barrier membrane procedure apparently gave a healing result beyond which further improvement could not be achieved by root surface conditioning.

A morphological comparison of radicular dentin following root planing and treatment with citric acid or tetracycline HCI

The conditioning of root surfaces with saturated solutions of citric acid or tetracycline is unpredictable in facilitating new attachment, perhaps due to the low pH of these solutions which may be denaturing the organic matrix of the root as well as demineralizing the surface. The purpose of the present study was to compare the effects of a saturated solution of citric acid (pH = 1) with that of a 0.5% solution of tetracycline HCl (pH = 3.2) on radicular dentin with regard to the removal of the smear layer, exposure of dentinal tubule openings, and demineralization of the peritubular dentin. 10 bovine incisors were used in this study. The crowns and apical 1/3 of the root were resected and the resulting root segments were then frozen in icy freon. The cementum was fractured off of the root to produce a fracture-exposed, non-instrumented dentin surface. This fracture-exposed dentin surface was divided into 4 specimens, the 1st being a fracture-exposed, non-instrumented dentin control specimen (FE). After removal of the (FE) specimen from the root segment, the remainder of the fracture-exposed dentin surface was thoroughly root planed and then subdivided into the 3 remaining specimens. One of these specimens served as the root planed dentin surface (RP); another specimen (CA) was immersed in saturated citric acid (pH = 1) for 5 min and then washed in water for 5 min; the final specimen (T) was immersed in a 0.5 mg/ml solution of tetracycline HCl for 5 min and rinsed in water for 5 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of crown‐attached sutures on healing of experimental furcation defects in dogs

This study evaluates whether suturing of replaced flaps with crown-attached sutures, following reconstructive surgery, counteracts postoperative recession of the gingival margins and facilitates new attachment. Through-and-through furcation defects were created in the mandibular premolars of 5 beagle dogs. Bone was surgically removed from the furcation and around each root to a level 3 to 4 mm below the cemento-enamel junction. Steel wires were placed in the furcations for 6 weeks to enhance plaque formation. After 12 weeks, reconstructive surgery that included acid conditioning of root surfaces was performed. On 1 side of the mandible, the flaps were replaced and secured by bonding the sutures to the teeth with composite resin. On the other side, the replaced flaps were sutured interdentally with single sutures. The results demonstrated that the margins of flaps secured with interdental sutures shifted apically to the fornix of the furcations after 1 week, and histologically all 10 furcations were found to be lined with epithelium. Margins of flaps secured with crown-attached sutures remained an average of 0.5 mm coronally to the fornix, and 13 of the 14 teeth showed new attachment. The results indicate that a suturing technique which counteracts gingival recession, favours the formation of new attachment in this beagle dog model.

Effect of flap placement and defect size on healing of experimental furcation defects.

Through‐and‐through furcation defects were experimentally created in one group of monkeys (Study 1) and in one group of dogs (Study 2). The effect of reconstructive periodontal surgery using citric acid conditioning of the instrumented root surfaces was studied. Two experimental variables were investigated: (1) variation of the placement and suturing of the flaps and (2) variation of the size of the furcation defects.The results of these studies indicate that adequate postoperative flap coverage of the furcations seems to be critical for successful healing of the furcation defects. Variations in the vertical dimension of the defects seems to play a secondary role. Future studies in experimental animals should evaluate methods which will provide improved post‐operative coverage of the furcation area during healing of furcation defects in human patients.

Pilot clinical studies on the effect of topical citric acid application on healing after replaced periodontal flap surgery.

The effect of citric acid conditioning of the root surfaces during periodontal surgery was studied in 12 patients with residual pockets ≥ 5 mm two months following oral hygiene instruction and initial root planing. Full thickness, replaced flap procedure (“modified Widman”) was performed with or without topical citric acid application using a split mouth approach. Six months post‐operatively, improvement of the periodontal conditions was observed as evidenced from reduction of probing pocket depth, gain of probing attachment level and gingival recession. A mean probing attachment level gain for pooled acid treated surfaces of 2.1 mm was obtained as compared to 1.5 mm for the non‐acid treated control surfaces.Our previous dog and human studies have demonstrated new connective attachment after acid conditioning of root surfaces as contrasted to readaplation of a junctional epithelium in the non‐acid treated controls. However, the results of the present study indicate that from a clinical standpoint, the use of citric acid application might only provide a small improvement in probing attachment levels.

Fast desensitization of tooth roots by topically applied SnF 2 and SrCl 2 in dogs

Incisor and canine buccal root surfaces in each of 5 dogs were exposed, planed and monitored for electrically induced sensitivity. After the post-surgical recovery of sensitivity (2–5 days), the root surfaces of 4 dogs were pretreated (daily for 4–7 days) either with pumicing and etching, pumicing only or brushing only in each of three quadrants in each dog. After a 30 min interval, 30 min topical applications of 10 per cent SnF 2 (water solution) or 1 per cent SrCl 2 (Sensodyne toothpaste) followed for 4–7 days. Comparisons of sensitivity tests before each treatment and 30 min after the end of each treatment revealed that desensitization was statistically effective for SnF 2 after pumicing and etching as well as after pumicing. Scanning electron microscopy displayed open dentinal tubules after pumicing and etching, scratches but no tubule openings after pumicing and a smooth, bacteria-containing film after brushing. Elemental analysis with an electron microprobe revealed deeper penetration of Sr than of F into the dentine. These results indicate the dependance of root surface conditioning for penetration of desensitizers and some differences between SnF 2 and SrCl 2 .