In vitro investigation of canine periodontal ligament-derived mesenchymal stem cells: A possibility of promising tool for periodontal regeneration.

Objectives: Recent investigations indicate that canine periodontal ligament-derived stem cells (cPDLSCs) may reveal a reliable strategy for repair of periodontal tissues via cell-based tissue engineering approaches. Due to limited research, this study aimed to demonstrate the phenotypic characterization of cPDLSc in comparison with canine bone marrow-derived mesenchymal stem cells (cBMSCs) in vitro. Methods: Mesenchymal stem cells (MSCs) were obtained from PDL and BM of five male adult Mongrel dogs. In vitro isolation and expansion as well as biologic characterization including colony unit formation (CFU), osteogenic and adipogenic differentiation, flow cytometric analysis of CD34 and CD44, and RT-PCR of alkaline phosphatase (ALP), osteocalcin (OCN), periostin (POSTN) and S100A4 were performed. Furthermore, electron microscopy analysis was done to complement the comparative research. Results: CFU assay revealed that colonies of cPDLSCs presented 70% confluency with a more finite lifespan than BM-MSCs, showing a significant increase in cPDLSCs. Both types of MSCs showed osteogenic and adipogenic phenotypic characterized with clusters of mineralized depositions and lipid vacuoles, respectively. Both types of MSCs expressed CD44 with limited expression of CD34. RT-PCR of cPDLSCs revealed that expression of ALP, POSTN, OCN and S100A4 genes were significantly higher than those of BMSCs. In addition, comparison of SEM and revealed that cPDLSCs expressed more extracellular collagen fibers. Conclusions: The current study indicated that cPDLSCs show potency as a novel cellular therapy for periodontal regeneration a large animal model.

Transplantation of Bone Marrow-Derived Mesenchymal Stem Cells, Platelet-Rich Plasma, and Fibrin Glue for Periodontal Regeneration.

Appropriate regeneration of periodontal tissues is the primary purpose of periodontal disease treatment. The present study assessed the impact of three key regenerative elements-platelet-rich plasma (PRP), canine bone marrow mesenchymal stem cells (cBM-MSCs), and fibrin glue-on periodontal regeneration. In each of the study's five dogs, Class II furcation defects were established on the buccal surface of five teeth. One tooth (five total) from each dog was placed into one of five groups: (1) PRP + fibrin glue, (2) PRP + fibrin glue + cBM-MSCs, (3) fibrin glue, (4) cBM-MSCs + fibrin glue, and (5) control (no treatment). Histologic and histometric evaluations were performed to assess the formation of new bone, cementum, and the periodontal ligament. Different types of new bone and cementum, the maximum thickness of new cementum and the periodontal ligament (PDL), the vitality of bone, and the presence of inflammation or foreign-body reactions were also elucidated. The histologic and histometric evaluations revealed substantial differences in all groups between the observed maximum thickness of newly formed cementum and PDL. The percentage of bone and cement formation drastically increased with the combined presence of stem cells, fibrin glue, and PRP. The results showed that the inherent regenerative capacity of periodontal tissues can be sufficient if their latent self-repair mechanisms are stimulated.

Microstructural Evaluation of Contaminated Implant Surface Treated by Laser, Photodynamic Therapy, and Chlorhexidine 2 percent.

PURPOSE: Decontamination of the rough surfaces of dental implants is a challenge in the treatment of peri-implantitis. An acceptable cleaning technique must be able to debride and detoxify the surface without traumatizing it. This study assessed the possible implant surface alterations following decontamination with laser, photodynamic therapy (PDT), and application of chlorhexidine (CHX). MATERIALS AND METHODS: Of 16 dental implants with sandblasted, large-grit, acid-etched surfaces, Aggregatibacter actinomycetemcomitans was cultured on the surfaces of 15 implants for 48 hours. These 15 implants were divided into five groups of three and were subjected to erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation, 630 nm light-emitting diode and toluidine blue O photosensitizer, 810 nm diode laser, and indocyanine green-based photosensitizer, 2% CHX, and control group (no treatment). One implant remained intact. The morphology and element/phase identification of the implants were studied using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS), respectively. RESULTS: The SEM images and EDS maps revealed that the decontamination methods did not alter the surface quality of the implants. However, in photodynamic therapy, sodium chloride that remained from rinsing liquid can make an adhesive layer on the surface of the treated implants. CONCLUSION: Er:YAG laser irradiation and PDT did not alter the surfaces of sandblasted, large-grit, acid-etched implants.

Effect of Propolis Extract in Combination with Eugenol-Free Dressing (Coe-PakTM) on Pain and Wound Healing after Crown-Lengthening: A Randomized Clinical Trial.

STATEMENT OF THE PROBLEM: Researchers have long been in search of products to enhance healing and patient comfort postoperatively. PURPOSE: This study aimed to assess the efficacy of propolis extract in combination with Coe-PakTM dressing for pain relief and wound healing after crown lengthening surgery. MATERIALS AND METHOD: This randomized clinical trial was performed on 36 patients who were randomly divided into two groups of Coe-PakTM dressing with (trial group) and without (control group) propolis extract. Pain and burning sensation by use of visual analog scale (VAS) and number of analgesics taken were asked from patients. Gingival color and consistency, bleeding on probing (BOP) and presence of infection were studied 7 days after dressing removal. RESULTS: Although a large number of patients in the trial group did not have burning sensation, this difference was not significant between the two groups (p> 0.05). In both groups, the majority of patients experienced moderate and mild pain and there was no pain in the trial group after three days. No significant difference was noted between the two groups in pain score and number of analgesics taken (p> 0.05). The two groups were not significantly different in terms of inflammation and healing process (BOP, gingival consistency and color), after 7 days (p> 0.05). CONCLUSION: The study results showed no difference in use of Coe-PakTM dressing with and without propolis extract in terms of postoperative pain and healing process following the crown lengthening surgery. More studies are required to confirm these results.

Perception of Laypeople and Dental Professionals of Smile Esthetics.

OBJECTIVES: This study aimed to assess and compare the perception of laypersons and dental professionals of smile esthetics based on two factors namely gingival display and alignment of teeth. MATERIALS AND METHODS: A total of 32 females were randomly selected among dental students in the International Campus of School of Dentistry, Tehran University of Medical Sciences (Tehran, Iran) with no previous history of esthetic dental work. Frontal photographs were obtained and cropped from the subnasal to menton areas of subjects to standardize the size of pictures. Three series of slides were prepared of the pictures using Microsoft PowerPoint software. The first series of slides were shown to familiarize the observers with the images. The second and third series were displayed for the observers and they were then asked to fill out a questionnaire. The group of observers included 10 dental specialists and 10 laypersons. Each observer was given a visual analog scale (VAS) chart for scoring (1-10). After completion of the questionnaires, data were transferred to a computer and the differences in judgments of professionals and laypeople were analyzed using the Mann Whitney test. RESULTS: No significant difference was found in the judgments of professionals and laypeople on evaluating overall smile esthetics, gingival display and alignment of teeth except for the slide showing a reverse smile arc. CONCLUSIONS: Laypeople and professionals had similar perceptions of smile esthetics. Thus, it appears that clinicians can rely on the judgment of laypersons in esthetic dental treatments.

Bactericidal Effect of Erbium-Doped Yttrium Aluminum Garnet Laser and Photodynamic Therapy on Aggregatibacter Actinomycetemcomitans Biofilm on Implant Surface.

PURPOSE: Peri-implantitis is a common complication of dental implants. The first step of treatment is elimination of bacterial biofilm and disinfection of the implant surface. This study sought to compare the effects of an erbium-doped yttrium aluminum garnet (Er:YAG) laser, photodynamic therapy using an indocyanin green-based photosensitizer (ICG-based PS) and diode laser, toluidine blue O (TBO) photosensitizer and light-emitting diode (LED) light source, and 2% chlorhexidine (CHX) on biofilm of Aggregatibacter actinomycetemcomitans to sandblasted, large-grit, acid-etched (SLA) implant surfaces. MATERIALS AND METHODS: Fifty SLA implants were divided into five groups and were incubated with A actinomycetemcomitans bacteria to form bacterial biofilm. Group 1 underwent Er:YAG laser radiation (with 10-Hz frequency, 100-mJ energy, and 1-W power); group 2 was subjected to LED (with 630-nm wavelength and maximum output intensity of 2.000 to 4.000 mW/cm(2)) and TBO as a photosensitizer; group 3 was exposed to diode laser radiation (with 810-nm wavelength and 300-mW power) and ICG-based PS; and group 4 was immersed in 2% CHX. Group 5 was the control group, and the samples were rinsed with normal saline. The number of colony-forming units (CFU) per implant was then calculated. Data were analyzed using one-way analysis of variance (ANOVA), and the five groups were compared. RESULTS: Significant differences was found between the control group and the other groups (P < .01). The lowest mean of CFU per implant count was in group 4 (P < .01), and the highest mean belonged to the control group. Photodynamic therapy by TBO + LED and ICG-based PS + diode laser was more effective than Er:YAG laser irradiation in suppression of this organism (P < .01). There was no significant difference between groups 2 and 3. CONCLUSION: The antibacterial effect of 2% CHX was greater than that of other understudy methods.

Effect of Chlorhexidine Application Protocol on Durability of Marginal Seal of Class V Restorations.

OBJECTIVES: This study aimed to evaluate the effect of chlorhexidine (CHX) application protocol on durability of marginal seal of class V composite restorations. MATERIALS AND METHODS: Class V cavities (4×2×1.5mm) were prepared in the buccal surfaces of 160 human third molars. The teeth were randomly divided into five groups (n=32) of (G1) CHX+rinse+etching, (G2) CHX+etching, (G3) etching+CHX+rinse, (G4) etching+ CHX, and (G5) etching alone as the control group. Adper Single Bond 2 was applied as an etch and rinse (E & R) bonding system. Cavities were filled with Z350 composite. Half of the teeth in each group were stored in distilled water for 24 hours and the other half were thermocycled (10,000 cycles, 5-55°C). For dye penetration test, the teeth were sectioned buccolingually and assessed at the enamel and dentin margins under a stereomicroscope at ×20 magnification. The Kruskal-Wallis, Dunn and Mann-Whitney tests were used for statistical analyses. RESULTS: There was no significant difference in immediate microleakage among the groups at the enamel and dentin margins (P= 0.894). After thermocycling, there was significantly less microleakage in G4 than the control group at dentin margin. There were significant differences in microleakage between G4 and G1(P=0.002), G4 and G2 (P=0.001) and G4 and G5 (P= 0.001) at dentin margin. CONCLUSIONS: Application of CHX after etching without rinsing is effective to decrease microleakage. However, it has no effect if applied before etching in use of this particular type of E & R adhesive after thermocycling.

Effect of Re-Etching of Oxalate-Occluded Dentin on Microleakage of Composite Resin Restorations.

OBJECTIVES: This study aimed to assess the effect of re-etching of desensitized dentin for five and 10 seconds on marginal microleakage of composite restorations. MATERIALS AND METHODS: Class V cavities (4×2×2mm) were prepared on the buccal surfaces of 64 third molars and randomly divided into four groups of 16. In the control group, Single Bond (SB) adhesive was applied after etching. In BB+SB group, after application of BisBlock (BB) desensitizer agent (which needs etching), SB adhesive was used. In BB+5E+SB group, re-etching of dentin was done for five seconds after application of desensitizer, and then the adhesive was applied. The process in BB+10E+SB was the same as BB+5E+SB group except for re-etching time, which was 10 seconds. The cavities were restored with composite resin. After 24 hours of storage in distilled water and 10,000 thermal cycles, all samples were subjected to dye penetration test. The teeth were sectioned buccolingually in the middle of restorations. A blind examiner observed the sections under a stereomicroscope. RESULTS: At the occlusal margins, no significant difference in microleakage was observed among the groups (P>0.05). Application of BB in combination with SB had no effect in comparison to the control group (P>0.05); while there were significant differences in microleakage scores between BB+10E+SB and control (P=0.002), BB+10E+SB and BB+SB (P<0.001) and BB+5E+SB and BB+SB groups (P=0.009). CONCLUSIONS: Dentin re-etching after application of BB desensitizer increased the gingival microleakage of class V composite restorations. Application of BB desensitizer combined with SB adhesive enhanced marginal seal.

Effect of a Desensitizing Varnish on Microleakage of Two Self-Etch Adhesives.

OBJECTIVES: The aim of this in-vitro experimental study was to assess the effect of application of a desensitizing varnish on the enamel and dentin marginal seal. MATERIALS AND METHODS: Seventy-two freshly extracted, intact human premolar teeth were divided into four groups (n=18). Class V cavities (3mm in length, 2mm in width and 2mm in depth) were prepared on the buccal surface of each tooth. The following sealing materials were applied in the four groups: One-step Clearfil S3 Bond (S3) self-etch adhesive, two-step Clearfil SE Bond (SE) self-etch adhesive, S3 Bond+ VivaSens desensitizing varnish (VS+S3) and Clearfil SE Bond + VivaSens (VS+SE). The cavities on the teeth were then incrementally filled with Z350 light-cure composite. The teeth were stored in distilled water for 24 hours at 37°C, and were then thermocycled for 1000 cycles. Then, all the specimens were prepared for dye penetration test and were immersed in 2% basic fuchsin dye and incubated at 37°C for 24 hours. The teeth were then sectioned buccolingually along the center of restorations with a diamond disk. Microleakage at the tooth-restoration interface was assessed in the enamel and dentin margins blindly using dye penetration under a stereomicroscope at ×20 magnification. RESULTS: There was significantly greater leakage at the enamel and dentin margins in group VS+SE than in group SE; also, these values were higher in group VS+S3 than in S3. CONCLUSION: Combined application of desensitizing varnish and self-etch adhesives seems to increase microleakage in composite restorations. Thus, its application is not suggested.

Implant site development by orthodontic forced eruption of nontreatable teeth: a case report.

BACKGROUND: Loss of bone and soft tissue attachment are common sequelae of periodontitis that may jeopardize the aesthetic outcome and compromise the functional and aesthetic outcomes of treatment. The following case report describes one of the most predictable techniques of vertical ridge augmentation, which is orthodontic extrusion or forced eruption of hopeless teeth. METHOD: A 34-year-old woman who presented with severe attachment loss and deep pockets was diagnosed with generalized aggressive periodontitis. The mobile maxillary incisors were consequently extracted and were replaced with dental implants. However, prior to extraction, orthodontic extrusion of the hopeless incisors was performed to correct vertical ridge defects. Following extrusion and extraction of the maxillary incisors, to prevent soft tissue collapse and to preserve the papillae during socket healing, the crowns of the extracted teeth were used as pontics on a removable partial provisional denture. After 8 weeks, the implants were placed, and an immediate functional restoration was delivered. After 4 months of healing, a fixed definitive partial prosthesis was fabricated and delivered. RESULT: After periodontal treatment, over a 2-year period, the progression of aggressive periodontitis was controlled. The mean vertical movement of marginal bone was 3.6 mm. The use of the crowns of extracted teeth appears to be an effective method to maintain papillae. CONCLUSIONS: Orthodontic extrusion is a predictable method for the correction of vertical ridge defects. Orthodontic treatment does not aggravate or hasten the progression of aggressive periodontitis.