Periodontal Reattachment Research Articles

Isolation and cultivation as well as in situ identification of MSCs from equine dental pulp and periodontal ligament.

The lifelong eruption places a great demand on the dental pulp and periodontal ligament (PDL) of horse teeth. Cells within the pulp and PDL seem to play a key role during this remodeling. In this study, we isolated and cultivated MSCs (medicinal signaling cells) from dental pulp, PDL and retrobulbar fat of four horses. Subsequently, we analyzed them by flow cytometry and immunohistochemistry to determine and compare their characteristics. In addition, we localized these cells within the tissue structure via immunohistochemistry of histological sections. For these analyses, several surface markers were applied. The described method illustrates a feasible approach to isolate and cultivate MSCs from equine dental pulp and PDL. In the flow cytometry a vast majority of cultivated cells were positive for CD90 and CD40 and negative for CD11a/18, CD45, CD105 and MHCII suggesting that these cells feature characteristics of MSCs. Immunohistochemistry of histological pulp and PDL sections showed the localization of CD90 positive cells especially in the perivascular region and the subodontoblastic layer. Our findings indicate that the isolation and cultivation of MSCs from equine dental pulp and PDL is feasible although an elaborate and complicated harvesting protocol is required. MSCs isolated from dental pulp and PDL are regarded as candidates for new therapeutical approaches in equine dental medicine like regeneration of periodontal lesions, enhancement of periodontal re-attachment after dental replantation and stimulation of pulp-obliteration and apexification in combination with endodontic therapies.

Screening of functionalized collagen membranes with a porcine periodontal regeneration model.

Current methods for periodontal regeneration do not promote collagen fiber insertions into new bone and cementum. We used a pig wound model to screen different functionalized collagen membranes in promoting periodontal reattachment to root surfaces. Treatment groups included (1) control with no membranes, (2) collagen-coated membranes, (3) membranes with insulin-like growth factor-1 (IGF-1), (4) membranes with amelotin, or (5) membranes attached with calcium phosphate cement (CPC), or with CPC combined with IGF-1. Flap procedures were performed on mandibular and maxillary premolars of each pig. Histomorphometric, micro-CT, and clinical measurements obtained at 4 and 12 weeks after surgery showed cementum formation on denuded roots and reformation of alveolar bone, indicating that the pig model can model healing responses in periodontal regeneration. Calcium phosphate cement simplified procedures by eliminating the need for sutures and improved regeneration of alveolar bone (p < 0.05) compared with other treatments. There was a reduction (p < 0.05) of PD only for the IGF group. Large observed variances between treatment groups indicated that a priori power analyses should be conducted to optimize statistical analysis. Pigs can model discrete elements of periodontal healing using collagen-based, functionalized membranes. Screening indicates that membrane anchorage with calcium phosphate cements improve regeneration of alveolar bone.

Periodontal response to a tricalcium silicate material or resin composite placed in close contact to the supracrestal tissue attachment: a histomorphometric comparative study.

Subgingival dental restorations and periodontal health have been studied for many years; however, there is a low histological evidence on the behavior of new materials in the supracrestal tissue attachment. The aim of this study is to analyze the periodontal response when a tricalcium silicate material (TSM) or composite margin restorations is placed to 0.5 mm and 1.5 mm from the bone crest with a histomorphometric analysis in dogs. Nine mongrel dogs were used in this study: four dogs (8 canine teeth) for TSM group, 4 dogs (8 canine teeth) for composite group, and 1 dog (2 canine teeth) with cavities without restorations. Cavity preparation of 2×2×1 mm was created on the buccal aspect of the canines at 0.5 and 1.5 mm of the crestal bone. Cavities were restored with composite and TSM or were left unrestored as control. After 12 weeks of healing, the dogs were euthanized and blocks containing the tooth and soft tissues were processed. In all the specimens, the junction epithelium was stablished apical to the tooth preparations. A shorter distance to the bone (0.5 cavity) implies greater apical periodontal migration regardless of the material used. In the TSM groups, the connective tissue height and the distance between bone level and apical margin preparation were greater than those in the composite groups, while the epithelium height was less. However, there were no statistically significant differences comparing TSM and composite groups at either 0.5 mm or 1.5 mm (p > 0.05). Histologic analysis did not show periodontal reattachment to TSM or composite. In both cases, bone crest migrates apically. For that reason, it is recommended to perform composite restorations at the subgingival level whenever the distance to the bone crest is at least 2 mm. Both composite and TSM do not achieve reinsertion of the connective tissue in the biological width.

Ozonated olive oil gel versus nano-silver mouthwash in root biomodification: A scanning electron microscopic study

Aim: This in vitro scanning electron microscopic (SEM) study was planned to assess and compare the effect of ozone gel versus nano-silver mouthwash when used as a root bio-modifier on the surface of the periodontally affected extracted roots. Materials and Methods: Twenty single-rooted teeth were selected for this in vitro cross-sectional study. The teeth were decoronated and split longitudinally to form 40 radicular halves. They were randomly allocated to four groups of 10 fragments each. Then, the other groups were scaled. Group 1: left untreated (non-scaled) (Negative control group). Group 2: treated with saline (Positive control group). Group 3: treated with ozone gel 20:25 µgm/ml concentration. Group 4: treated with nano-silver mouthwash. The specimens were prepared to undergo scanning electron microscopy and elemental analysis (SEM-EDX) to determine the percentage of calcium (Ca) atom. Further, the acquired photomicrographs were evaluated for the presence of calculus, smear layer, and product residues and they were analyzed using Fisher Exact test followed by Dunn’s test. SEM-EDX were analyzed by ANOVA test followed by Tukey’s post hoc test for a pairwise comparison between groups. Results: The nano-silver mouthwash treated group showed the absence of the smear layer and calculus and had significantly higher residue levels than ozone-treated specimens (P = 0.001), whereas the ozone group showed that the smear layer was not completely removed with the absence of remnant of the material. The negative control group scored the highest level in the presence of calculus compared with other examined groups (P = 0.001). Interestingly, the nano-silver treated group showed a significant decrease in Ca levels compared with all other experimental groups. Conclusion: The nano-silver mouthwash removed the smear layer effectively and provided notable substantivity, as evidenced by the presence of the material remnant after application. Moreover, it decreased Ca level significantly compared with all other experimental groups, which is expected to increase cellular attachment and proliferation. Thus, using the nano-silver mouthwash as a root bio-modifier could yield better results in periodontal reattachment.

Adenovirus-Mediated LAMA3 Transduction Enhances Hemidesmosome Formation and Periodontal Reattachment during Wound Healing

A robust dento-epithelial junction prevents external pathogenic factors from entering connective tissue and could be crucial for periodontal reattachment after periodontal surgery. The junctional epithelium (JE) is attached to the tooth surface through the hemidesmosome (HD) and internal basal lamina, where the primary component is laminin-332. Destruction of the JE leads to the loss of periodontal attachment. Traditional treatments are effective in eliminating local inflammation of the gingiva; however, few directly promote periodontal reattachment and HD formation. Here, we designed a gene-therapy strategy using the adenovirus-mediated human laminin-332 α3 chain (LAMA3) gene (Ad-LAMA3) transduced into a human-immortalized epidermal cell line (HaCaT) to study the formation of HD in vitro. Ad-LAMA3 promoted early adhesion and fast migration of HaCaT cells and increased expression of LAMA3 and type XVII collagen (BP180) significantly. Furthermore, HaCaT cells could facilitate formation of mature HDs after LAMA3 overexpression. In vivo experiments demonstrated that the JE transduced with Ad-LAMA3 could increase expression of LAMA3 and BP180 and “biological sealing” between the tooth and gingival epithelium. These results suggested that adenovirus-mediated LAMA3 transduction is a novel therapeutic strategy that promotes the stability and integration of the JE around the tooth during wound healing.

Evaluation of 660nm LED light irradiation on the strategies for treating experimental periodontal intrabony defects.

This study aims to investigate the therapeutic value of 660nm light-emitting diode (LED) light irradiation on the strategies for treating experimental periodontal intrabony defects in vivo. Large-sized periodontal intrabony defects were created bilaterally on the mesial aspect of the maxillary second molars of 48 Sprague-Dawley rats, and the rats were equally divided into four treatment groups with primary wound intention (n = 6/treatment/time point), including open flap debridement alone (OD), barrier membrane alone (MB), xenograft alone (BG), and xenograft plus barrier membrane (MG). Each group received daily 0 or 10J/cm(2) LED light irradiation. The animals were sacrificed after 1 or 4weeks. The treatment outcome was evaluated by gross observation of wound dehiscence and healing, micro-CT imaging for osteogenesis, and histological assessments for inflammatory cell infiltration and periodontal reattachment. With LED light irradiation, the extent of wound dehiscence was reduced, wound closure was accelerated, epithelial downgrowth was prevented, inflammation was reduced, and periodontal reattachment was promoted in all treatment strategies. Significant reduction of inflammation with LED light irradiation was noted at 1week in the groups BG and MG (p < 0.05). Osteogenesis was significantly promoted only in the group OD at both time points (p < 0.05). Our study showed that 660nm LED light accelerates mucoperiosteal flap healing and periodontal reattachment. However, the enhancement of osteogenesis appeared to be limited while simultaneously treating with a barrier membrane or xenograft.

The biomechanical role of periodontal ligament in bonded and replanted vertically fractured teeth under cyclic biting forces.

After teeth are replanted, there are two possible healing responses: periodontal ligament healing or ankylosis with subsequent replacement resorption. The purpose of this study was to compare the fatigue resistance of vertically fractured teeth after bonding the fragments under conditions simulating both healing modes. Thirty-two human premolars were vertically fractured and the fragments were bonded together with Super-Bond C&B. They were then randomly distributed into four groups (BP, CP, CA, BA). The BP and CP groups were used to investigate the periodontal ligament healing mode whilst the BA and CA groups simulated ankylosis. All teeth had root canal treatment performed. Metal crowns were constructed for the CP and CA groups. The BP and BA groups only had composite resin restorations in the access cavities. All specimens were subjected to a 260 N load at 4 Hz until failure of the bond or until 2×106 cycles had been reached if no fracture occurred. Cracks were detected by stereomicroscope imaging and also assessed via dye penetration tests. Finally, interfaces of the resin luting agent were examined by scanning electron microscope. The results confirmed that the fatigue resistance was higher in the groups with simulated periodontal ligament healing. Periodontal reattachment showed important biomechanical role in bonded and replanted vertically fractured teeth.

Treatment of a lateral incisor anatomically complicated with palatogingival groove

Objectives: Palatogingival groove is a developmental anomaly that starts near the cingulum of the tooth and runs down the cementoenamel junction in apical direction, terminating at various depths along the roots. While frequently associated with periodontal pockets and bone loss, pulpal necrosis of these teeth may precipitate a combined endodontic-periodontal lesion. This case presents a case of a lateral incisor anatomically complicated with palatogingival groove. Methods: Two patients with lesion associated with the palatogingival groove were chosen for this report. Palatogingival grooves were treated with different restoration materials with endodontic treatment. Conclusions: Maxillary lateral incisor with a palatogingival groove may occur the periodontal disease with pulpal involvement. Elimination of groove may facilitate the periodontal re-attachment and prevent the recurrence. [J Kor Acad Cons Dent 2011;36(3):238-242.]

Immunohistochemical analysis of periodontal reattachment on denuded root dentin after periodontal surgery

This study evaluates the effects of three kinds of periodontal surgery using statistical analyses of histological and immunohistochemical indices. Dehiscence defects were made on roots of maxillary teeth in monkeys. Surgically exposed roots were untreated, etched with EDTA, or treated with Emdogain® after EDTA etching. Paraffin sections were stained with hematoxylin and eosin or immunostained for bone sialoprotein (BSP) or osteopontin (OPN) and analysed using several indices. The relative length of regenerated cementum and of BSP/OPN-immunoreactive lines on dentin defect showed no differences among the three groups. Regenerated cementum area was larger in the etching-Emdogain group than in the etching group.The attached regenerated cementum in the untreated group was shorter than in the etching groups. Thickness of immunolabeling on detached cementum was larger than that on attached cementum in all of the groups. These findings suggest that etching reinforces the attachment of regenerated cementum, and that BSP and OPN are associated with the attachment, where they exercise strong adhesion within a certain level of thickness.

Development of HydroxyCarbonate Apatite on hybrid polymers used in fixed restorations modified by bioactive glass

The incorporation of a bioactive glass in the structure of hybrid polymers used in dentistry for the construction of fixed prosthetic restorations could induce the expression of bioactivity, leading to the possibility of periodontal tissues reattachment. Hybrid polymer specimens and polymer specimens modified by bioactive glass were prepared and used as control for the surface morphology examination by Scanning Electron Microscopy with associated Dispersive Spectroscopy Analysis (SEM-EDS) and for surface characterization with Fourier Transform Infrared Spectroscopy (FTIR). Furthermore, hybrid polymer specimens modified by bioactive glass were immersed in simulated body fluid (SBF) at 37 °C for different time intervals and were examined by SEM-EDS and FTIR. After 4 days immersion time a dense and continuous apatite layer covered almost the entire modified surface of the specimens. The molar Ca/P ratio reached the value of 1.79. The apatite layer showed a thickness of 1?m and was attached to the substrate, while bioactive glass particles were still present in polymer mass. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Effect of periodontal root planing on dentin permeability

The purpose of this study was to quantitate the effects of root planing on the permeability of human root dentin in vitro. Unerupted 3rd molars were used. The crowns were removed and longitudinal slices made of the root. The hydraulic conductance of the root dentin was measured before and after root planing, acid etching and potassium oxalate application using a fluid filtration method. The results showed that root planing creates a smear layer that reduces the permeability of the underlying dentin. However, this smear layer is acid labile. Thus, root planing may ultimately cause increased dentin permeability and the associated sequelae of sensitive dentin, bacterial invasion of tubules, reduced periodontal reattachment and pulpal irritation.

Sharpening of ultrasonic sealers

Instruments suitable for removing calculus, plaque and necrotic cementum, which hinder normal periodontal reattachment, are extremely important for successful therapy. The test was carried out in order to see if a standard scaler used for ultrasonic tartar removal maintains its physical features when sharpened. 6 scalers, compatible with piezo-electric generators, were tested and 2 diameters, A and B, weights and resonance frequencies were measured. Scalers no. 2, 3, 4, 5, were sharpened and was used as control. All measurements were taken again at the end of the test. Statistical analysis reveals significant variations, after sharpening, of A diameter (t = 4.14 greater than 3.55, p less than 0.01), B diameter (t = 5.34 greater than 3.355, p less than 0.01) and resonance frequency (t = 2.82 greater than 2.306, p less than 0.05); in contrast, there is no significant change of weights (t = 1.17 less than 2.306, p greater than 0.05). These results suggest that sharpening slightly modifies the physical features of ultrasonic tips, so that sharpening ultrasonic scalers, from a physical point of view, can be carried out, paying attention not to damage the water cooling system.

Long-term culture of human periodontal ligament cells with autologous root discs.

Recent attempts at gaining an understanding of the factors necessary for periodontal reattachment have employed an in vitro system in which connective tissue cells are cultured with dental root discs. The present study was undertaken to optimize culture conditions. Periodontal ligament (PDL) cells and root discs were derived from 2 wisdom teeth extracted from each of 3 patients. Pairs of planed root discs (0.5 mm thick) were gently placed in dishes containing autologous PDL‐cells and separated by a 0.5 mm wide gap. After 10 to 13 weeks in culture the specimens were processed for light‐ and electron microscopy and the collagen fibril diameter was determined. In the interdental space, all cultures contained an aggregate of cells and collagen fibrils. Adherent to root discs with exposed dentin was a loose capsule of cells and collagen fibrils oriented parallel to the disc surface. Adjacent to cellular cementum a discontinuous, dense, short fiber fringe was found along the cultureJroot interface. There was some intermingling between cemental and culture collagen fibrils. The fibril diameter of cemental collagen (59.4 ± 5.0 nm) and culture collagen (31.8 ± 3.5 nm) was very different. Thus, autologous PDL‐cell/disc‐cultures can be maintained for prolonged periods of time, resulting in the formation of discontinuous patches of condensed collagen fibrils radiating from some portions of the decalcified cemental surface.

Effect of the endodontic status of the tooth on experimental periodontal reattachment in baboons: A preliminary investigation

The effect of the endodontic status of the tooth on periodontal reattachment after the raising of a mucogingival flap was studied with the use of 48 teeth in four old baboons. Root canal therapy was performed on 26 front teeth. Tubliseal, AH26, N2, and Diaket were used as sealers with gutta-percha. The pulps of 5 teeth were exposed and left infected; 17 teeth with intact pulps served as a control. The teeth and their surrounding structures were studied histologically for reattachment with new cementum formation 2 to 17 days, 1 to 2 months, and up to 1 year after the operation. In the teeth examined 1 month postoperatively or more, if epithelium had not covered the denuded surface, new cementum was present, regardless of the endodontic status.

Fibroblast subtypes in the periodontium. A possible role in connective tissue regeneration and periodontal reattachment.

Fibroblast subtypes in the periodontium. A possible role in connective tissue regeneration and periodontal reattachment.

Effect of pulp vitality on periodontal reattachment following free autogenous gingival graft in dog (author's transl)

The present study was to examine the effect of pulp vitality on the periodontal reattachment following the free autogenous gingival graft. Maxillary bilateral premolars in each of 4 dogs were used.Denuded root surfaces were prepared after the labial alveolar osteomies on the experimental region. Four weeks later, the pulp in the right teeth was extirpated and the root canals were filled with gutta percha points and root canal sealer or the root canals were left open (infected teeth). The left teeth were kept in the vital pulp as a control. The graft was placed over the denuded roots after 4 weeks.The animals were sacrified 4 and 12 weeks postoperatively and a serial section of the premolars with surrounding tissues was prepared for a light microscopic examination.The clinical and histopathological findings showed that the gingival recession was more found in the infected teeth than the vital teeth and the former produced less periodontal reattachment as compared with the latter, and the interface between the donor and the recipient bed was characterized by the increased number and size of blood vessels.

Effect of pulp vitality on periodontal reattachment following dentin exposure (author's transl)

This investigation was to determine the effect of pulp vitality on the periodontal reattachment after the periodontal surgery. Four maxillary premolars in each of 6 dogs were used in this study. The left teeth were kept in the vital pulp as a control. In the experimental right teeth the pulp was extirpated and the root canals were filled with gutta percha points and root canal sealer. Four weeks later, the mucoperiosteal flaps were elevated to provide access to the attachment apparatus and the buccal radicular bone was removed about 4mm to the apex and the cementum was also scraped away completely, leaving the denuded dentine. After the application of citric and hydrochloric acids at pH 1.0 to the denuded dentin surface for 2 minutes, the flaps were sutured. The animals were sacrificed at 4 and 12 weeks postoperatively. The blood vessel topography at dentogingival junction was observed after the perfusion with a carbon-gelatin mixture prior to the sacrifice.The periodontal tissues were dissected, fixed in 10 percent formalin, decalcified, embedded in paraffin. The serial buccolingual cross sections 8-10 microns thick were prepared and stained with hematoxylin and eosin and with Masson-Goldner.The histologic finding showed a correlation between the degree of periodontal attachment and the pulp status. A obvious new alveolar bone and new cementum formation occurred in the vital teeth. On the other hand, the marked apical epithelial shift was demonstrated in the pulpless teeth. In the present study a close relationship was found between the comentogenesis and the epithelial migration. (r=-0.71)It could be concluded that the vital teeth produced better periodontal reattachment than the non-vital teeth.

Effects of citric acid on diseased root surfaces.

The effect of topically applied citric acid on periodontally diseased root surfaces was evaluated using the scanning (SEM) and transmission (TEM) electron microscopes. Results with the SEM indicate that acid application had no effect on specimens that had not been root planed. After application to root planed surfaces, however, the acid priduced a fiber‐like surface with frequent depressions. TEM observations showed that the acid application produced a four micron wide demineralized zone, which was characterized by exposed collagen fibrils. These fibrils seemed to be continuous between the mineralized and demineralized zones of the root.It appears that the relative success of the citric acid application in periodontal reattachment procedures is realted to the fact that the acid causes exposure of collagen fibrils in the dentin matrix, thus providing a suitable nidus for splicing with new fibrils during the healing process.

Periodontal Reattachment: Clinical and Roentgenological Evidence / Case of Penicillin Allergy

Periodontal Reattachment: Clinical and Roentgenological Evidence / Case of Penicillin Allergy