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Hyaluronic acid (HA) affects angiogenesis and promotes the migration and differentiation of mesenchymal cells, thereby activating the osteogenic ability of osteoblasts. Although studies on the action of HA during bone regeneration are being actively conducted, the optimal dose of HA required for bone regeneration remains unclear. Therefore, the purpose of this study was to elucidate the most effective HA dose for bone formation using a rat critical-size defect model.Thirty rats were randomly divided into 5 groups, with 6 rats in each group. An absorbable collagen sponge soaked with HA or saline was used to fill an 8-mm defect, which was then covered with a collagen membrane. Different treatments were performed for each group as follows: (1) saline control, (2) 1 mg/mL HA, (3) 25 mg/mL HA, (4) 50 mg/mL HA, or (5) 75 mg/mL HA. After a healing period of 4 weeks, micro-computed tomography and histological analysis were performed. The obtained values were analyzed using analysis of variance and the Tukey test (At week 4, the 75 mg/mL HA group had the highest bone volume/total volume ratio, new bone, and bone fill among the 5 groups, and these values were significantly different from those observed in the control group (The 75 mg/mL HA group showed better bone formation than the other groups (1, 25, and 50 mg/mL HA and control).

The aim of this study was to evaluate the impact of polydeoxyribonucleotide (PDRN) on histologic outcomes when implant placement and lateral sinus floor elevation are performed simultaneously.Three bimaxillary premolars (P2, P3, and P4) were extracted from 4 beagle dogs 2 months before lateral sinus floor elevation. After lateral elevation of the sinus membrane, each sinus was allocated to either the test or control group. Sinuses underwent either 1) collagenated synthetic bone graft with PDRN following lateral sinus floor elevation (test group) or 2) collagenated synthetic bone graft without PDRN after lateral sinus floor elevation (control group). Eight weeks after the surgical procedure, all animals were euthanised for a histologic and histomorphometric assessment. Augmented height (AH), protruding height (PH), and bone-to-implant contact in pristine (BICAH, PH, BICThe histologic findings revealed that lateral sinus floor elevation with PDRN might improve early new bone formation and enable higher bone-to-implant contact.

We investigated whether repeated irradiation with light-emitting diodes (LEDs) at a combination of 470 nm and 525 nm could suppress the progression of experimental periodontitis.A experimental periodontitis model was established in the second, third, and fourth premolars of the mandible in beagle dogs for 2 months. The spontaneous progression of periodontitis was monitored under the specified treatment regimen for 3 months. During this period, the animals were subjected to treatments of either plaque control only (control) or plaque control with LED application (test) at 2-week intervals. The clinical parameters included the probing pocket depth (PPD), gingival recession (GR), and the clinical attachment level (CAL). Histomorphometric analysis was performed using measurements of the length of the junctional epithelium, connective tissue (CT) zone, and total soft tissue (ST).There were significant differences in PPD between the control and test groups at baseline and 12 weeks. When the change in PPD was stratified based on time intervals, it was shown that greater differences occurred in the test group, with statistical significance for baseline to 12 weeks, 6 to 12 weeks, and baseline to 6 weeks. There was no significant difference in GR between the control and test groups at any time points. Likewise, no statistically significant differences were found in GR at any time intervals. CAL showed a statistically significant difference between the control and test groups at baseline only, although significant differences in CAL were observed between baseline and 12 weeks and between 6 and 12 weeks. The proportion of CT to ST was smaller for both buccal and lingual areas in the control group than in the test group.Repeated LED irradiation with a combination of 470-nm and 525-nm wavelengths may help suppress the progression of periodontal disease.

BACKGROUND: The effect of nano controlled sequential release of trichloroacetic acid (TCA) and epidermal growth factor (EGF) on the oral soft tissue regeneration was determined. METHODS: Hydrophobically modified glycol chitosan (HGC) nano controlled system was developed for the sequential release of TCA and EGF, and the release pattern was identified. The HGC-based nano controlled release system was injected into the critical-sized defects created in beagles’ palatal soft tissues. The palatal impression and its scanned body was obtained on various time points post-injection, and the volumetric amount of soft tissue regeneration was compared among the three groups: CON (natural regeneration control group), EXP1 (TCA-loaded nano controlled release system group), EXP2 (TCA and EGF individually loaded nano controlled release system). DNA microarray analysis was performed and various soft tissue regeneration parameters in histopathological specimens were measured. RESULTS: TCA release was highest at Day 1 whereas EGF release was highest at Day 2 and remained high until Day 3. In the volumetric measurements of impression body scans, no significant difference in soft tissue regeneration between the three groups was shown in two-way ANOVA. However, in the one-way ANOVA at Day 14, EXP2 showed a significant increase in soft tissue regeneration compared to CON. High correlation was determined between the histopathological results of each group. DNA microarray showed up-regulation of various genes and related cell signaling pathways in EXP2 compared to CON. CONCLUSION: HGC-based nano controlled release system for sequential release of TCA and EGF can promote regeneration of oral soft tissue defects. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13770-019-00232-9) contains supplementary material, which is available to authorized users.

The following consensus report is based on four background reviews (Keeve et al., Implant Dent 2019 28(2): 177–186; Ramanauskaite et al., Implant Dent 2019 28(2): 187–209; Koo et al., Implant Dent 2019 28(2): 173–176; Sculean et al., Implant Dent 2019 210–216). The surgical treatment of peri-implantitis is indicated in the cases where the first choice of treatment, the non-surgical one, failed with recurrence of bleeding and suppuration. The aim of this review was to systematically screen the literature for possible surface decontamination techniques and material during surgical treatment, the surgical regenerative and non-regenerative treatments of peri-implantitis, radiological and clinical outcomes, the importance of the presence of fixed and or keratinised peri-implant gingiva, and to determine predictable therapeutic options for the clinical surgical management of peri-implantitis lesions. Existent clinical, radiographic and microbiological data do not favour any decontamination approaches and fail to show the influence of a particular decontamination protocol on surgical therapy. Using implantoplasty in surgical non-regenerative treatment leads to a significant decrease in bleeding on probing and probing depth, and may result in improvement of clinical and radiographic parameters, up to 3 years after surgery compared with mechanical debridement alone. Surgical augmentative peri-implantitis therapy resulted in improved clinical and radiographic treatment outcomes compared with the baseline in the majority of studies with 6 months to 7–10 years of follow-up. There is no evidence to support the superiority of a specific material, product or membrane in terms of long-term clinical benefits. The best treatment modality to improve the width of keratinised attached mucosa and bleeding and plaque scores, and to sustain the peri-implant marginal bone level, is the use of an apically positioned flap combined with a free gingival graft.

Purpose To investigate the histologic differences between immediate implants placed in chronically infected sites and noninfected sites in a canine model. The histologic results of immediate implant placement also were evaluated on the basis of healing time and implant surface modification. Materials and methods Chronic endodontic-periodontic combined lesions were induced on the second, third, and fourth premolars of the hemimandible in six dogs, with the contralateral teeth as controls. Implants were immediately placed following the infected and noninfected tooth extractions using implants with a machined surface, sandblasted with alumina and acid-etched surface, and chemically modified sandblasted with alumina and acid-etched with calcium solution surface. After 1 and 3 months, three dogs were euthanized and the bone-to-implant contact, bone area fraction occupied, buccal and lingual first bone-to-implant contact from the implant platform, and buccal and lingual marginal bone loss were calculated. Results On histologic evaluation, no inflammation was observed around implants placed in the infected or noninfected sockets. At 1 month, no statistically significant differences were observed between the infected and noninfected sockets in buccal marginal bone loss in the machined implant group (P = .046), lingual first bone-to-implant contact from the implant in the sandblasted with alumina and acid-etched group (P = .046), lingual marginal bone loss in the sandblasted with alumina and acid-etched implant group (P = .028), buccal first bone-to-implant contact from the implant platform in the chemically modified sandblasted with alumina and acid-etched with calcium solution group (P = .028), and lingual first bone-to-implant contact from the implant platform in the chemically modified sandblasted with alumina and acid-etched with calcium solution group (P = .046). At 3 months, no statistically significant differences were observed in parameters between the infected and noninfected sockets for three implant surfaces. Differences between the infected and noninfected sockets were observed between the machined and sandblasted with alumina and acid-etched implant at 1 month (P = .023). Conclusion Immediate implant placement in an infected socket did not lead to any differences when compared with placement in a noninfected socket when sufficient healing time was provided.

Background Three- dimensional (3D) technology has been suggested to overcome these limitations in guided bone regeneration (GBR) procedures because 3D-printed scaffolds can be easily molded to patient-specific bone defect site. This study aimed to investigate the effect of 3-D printed polylactic acid (PLA) scaffolds with or without hyaluronic acid (HA) in a rabbit calvaria model. Methods A calvaria defect with a diameter of 15 mm was created in 30 New Zealand white rabbits. The rabbits were randomly allocated into 3 groups including no graft group (control, n = 10) , 3D printed PLA graft group (3D-PLA, n = 10) , and 3D printed PLA with hyaluronic acid graft group (3D-PLA/HA, n = 10) . Five animals in each group were sacrificed at 4 and 12 weeks after surgery. Microcomputed tomography and histologic and histomorphometric analyses were performed. Results Over the whole examination period, no significant adverse reactions were observed. There were no statistically significant differences in bone volume (BV) /tissue volume (TV) among the three groups at 4 weeks. However, the highest BV/TV was observed in the 3D-PLA/HA group at 12 weeks. The new bone area for control, 3D-PLA, and 3D-PLA/HA showed no statistical differences at 4 weeks. However, the value was significantly higher in the 3D-PLA and 3D-PLA/HA groups compared to the control group at 12 weeks. Conclusion The 3D printed PLA scaffolds was biocompatible and integrated well with bone defect margin. They were also provided the proper space for new bone formation. Therefore, 3D printed PLA/HA might be a potential tool to enhance bone augmentation. This article is protected by copyright. All rights reserved.

Background The aim of this study was to evaluate the efficacy of deproteinized bovine bone mineral with 10% collagen (DBBM-C) soaked with hyaluronic acid (HA) for ridge preservation in compromised extraction sockets. Methods Bilateral third, fourth premolars and first molar were hemisected, distal roots were extracted, and then combined endodontic periodontal lesion was induced in the remaining mesial roots. After 4 months, the mesial roots were extracted and the following four treatments were randomly performed: Absorbable collagen sponge (ACS), ACS soaked with HA (ACS+HA), Ridge preservation with DBBM-C covered with a collagen membrane (RP), Ridge preservation with DBBM-C mixed with HA and covered with a collagen membrane (RP+HA). Animals were sacrificed at 1 and 3 months following treatment. Ridge dimensional changes and bone formation were examined using microcomputed tomography, histology, and histomorphometry. Results At 1 month, ridge width was significantly higher in the RP and RP+HA groups than in the ACS and ACS+HA groups, while the highest proportion of mineralized bone was observed in ACS+HA group. At 3 months, ridge width remained significantly higher in the RP and RP+HA groups than in the ACS and ACS+HA groups. ACS+HA and RP+HA treatments featured the highest proportion of mineralized bone and bone volume density compared to the other groups. No statistical difference was observed between ACS+HA and RP+HA treatments. Conclusions Ridge preservation with the mixture DBBM-C/HA prevented dimensional shrinkage and improved bone formation in compromised extraction sockets at 1 and 3 months. This article is protected by copyright. All rights reserved, One sentence summary. The mixture of hyaluronic acid and deproteinized bovine bone mineral with 10% collagen in compromised extraction sockets can improve bone formation and prevent dimensional shrinkage.

This study aims to investigate and assess salivary biomarkers and microbial profiles as a means of diagnosing periodontitis. A total of 121 subjects were included: 28 periodontally healthy subjects, 24 with Stage I periodontitis, 24 with Stage II, 23 with Stage III, and 22 with Stage IV. Salivary proteins (including active matrix metalloproteinase-8 (MMP-8), pro-MMP-8, total MMP-8, C-reactive protein, secretory immunoglobulin A) and planktonic bacteria (including Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas nigrescens, Parvimonas micra, Campylobacter rectus, Eubacterium nodatum, Eikenella corrodens, Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, and Actinomyces viscosus) were measured from salivary samples. The performance of the diagnostic models was assessed by receiver operating characteristics (ROCs) and area under the ROC curve (AUC) analysis. The diagnostic models were constructed based on the subjects&rsquo, proteins and/or microbial profiles, resulting in two potential diagnosis models that achieved better diagnostic powers, with an AUC value &gt, 0.750 for the diagnosis of Stages II, III, and IV periodontitis (Model PA-I, AUC: 0.796, sensitivity: 0.754, specificity: 0.712) and for the diagnosis of Stages III and IV periodontitis (Model PA-II, AUC: 0.796, sensitivity: 0.756, specificity: 0.868). This study can contribute to screening for periodontitis based on salivary biomarkers.

The purpose of this study was to compare the implant survival, peri-implant marginal bone level, and peri-implant soft tissue of three different types of implants. This was performed with an early loading protocol, using a complete digital workflow, for one year of follow-up. Twenty-four patients with a single missing tooth in the mandibular posterior region were randomly assigned to the control group (SLActive Bone level implant; Institut Straumann AG, Basel, Switzerland), experiment group 1 (CMI IS-III Active implant; Neobiotech Co., Seoul, Korea), and experiment group 2 (CMI IS-III HActive implant; Neobiotech Co., Seoul, Korea). For each patient, a single implant was installed using the surgical template, and all prostheses were fabricated using a computer-aided design/computer-aided manufacturing system on a 3-dimensional model. A provisional prosthesis was implanted at 4 weeks, and a definitive monolithic zirconia prosthesis was substituted 12 weeks following the implant placement. The implant stability quotient (ISQ) and peri-implant soft tissue parameters were measured, and periapical radiographs were taken at 1, 3, 4, 8, 12, 24, 36, and 48 weeks after implant placements. Seven implants in the control group, nine implants in the experiment 1 group, and eight implants in the experiment 2 group were analyzed. There were no significant differences among the three groups in terms of insertion torque, ISQ values between surgery and 8 weeks of follow-up, marginal bone loss at 48 weeks of follow-up, and peri-implant soft tissue parameters (P > 0.05). Statistically significant differences in ISQ values were observed between the control and experiment 1 groups, and the control and experiment 2 groups at the 12 to 48 weeks’ follow-ups. Within the limits of this prospective study, an early loading protocol can be applied as a predictable treatment modality in posterior mandibular single missing restorations, achieving proper primary stability.

Background To minimize alveolar bone resorption, alveolar ridge preservation (ARP) has been proposed. Recently, interest in improving the feasibility of implant placement has gradually increased, especially in situations of infection such as periodontal and/or endodontic lesions. The aim of this study was to investigate if ARP improves feasibility of implant placement compared with no ARP in periodontally compromised sites. Secondary endpoints were the necessity of bone graft at the time of implant placement and implant failure before loading at ARP compared with no ARP. Material and methods This retrospective study was performed using dental records and radiographs obtained from patients who underwent tooth extraction due to chronic periodontal pathology. Outcomes including the feasibility of implant placement, horizontal bone augmentation, vertical bone augmentation, sinus floor elevation, total bone augmentation at the time of implant placement, and implant failure before loading were investigated. Multivariable logistic regression analysis was performed to examine the influence of multiple variables on the clinical outcomes. Results In total, 418 extraction sites (171 without ARP and 247 with ARP) in 287 patients were included in this study. The ARP group (0.8%) shows significantly lower implant placement infeasibility than the no ARP group (4.7%). Horizontal and vertical bone augmentations were significantly influenced by location and no ARP. Total bone augmentation was significantly influenced by sex, location, and no ARP. Conclusion ARP in periodontally compromised sites may improve the feasibility of implant placement. In addition, ARP attenuate the severity of the bone augmentation procedure.

OBJECTIVE To verify whether ridge preservation is effective in the reduction of dimensional loss and in bone formation compared to spontaneous healing in extraction sockets of periodontally compromised teeth. METHODS Twenty-six subjects requiring tooth extraction for stage III/IV periodontitis were randomly assigned to one of two interventions: alveolar ridge preservation using collagenated bovine bone mineral and a resorbable collagen membrane (test, RP) or spontaneous healing (control, SH). Six months later, postoperative cone-beam computed tomography (CBCT) was performed to measure the linear and volumetric changes of the sockets compared to baseline scans. Biopsies were retrieved at the implant site for histomorphometric calculations. Nonparametric tests were applied for statistical analysis. RESULTS Significantly less shrinkage occurred in RP compared to SH, mainly in the crestal zone. The width loss difference between groups was 3.3 mm and 2.2 mm at 1 mm and 3 mm below the crest, respectively (p

Previous studies demonstrated that recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered using a collagen sponge could be a candidate for periodontal regeneration therapy. However, there is little evidence related to rhBMP-2 delivered with a bilayer collagen matrix. The aim of this study was to investigate the proper dose of rhBMP-2 using a bilayer collagen matrix for periodontal regeneration in a 1-wall defect. The mandibular first premolars and first molars of 6 beagle dogs were extracted, and an 8-week healing period was allowed. One-wall intrabony defects (4 mm in width and 5 mm in height) were made on the mesial side of the 2nd premolar and/or the distal side of the 4th premolar bilaterally. Subsequently, a bilayer collagen matrix containing 0 μg (C), 200 μg (T1), or 500 μg (T2) of lyophilized rhBMP-2 was randomly applied to the defect area. Calcein and xylenol orange were injected at 4 and 8 weeks following the surgery, respectively, to label periodic bone formation. After a 12-week healing period, the animals were sacrificed for micro-computed tomography and histomorphometric analysis. Bone mineral density and bone volume density showed statistically significant differences between the control group and group T1, while no significant differences were observed between the control group and group T2 or between groups T1 and T2. The bone height in groups T1 and T2 was smaller than that in the control group. Low doses of rhBMP-2 delivered using a bilayer collagen matrix in 1-wall intrabony defects can promote periodontal regeneration compared to no or high doses of rhBMP-2.

OBJECTIVE To test whether or not topically administered recombinant human epidermal growth factor (rhEGF) accelerates the early healing phase of oral soft tissue wounds. METHODS One day following the creation of palatal defects (n = 6/animal), 14 dogs were allocated to one of the following five groups: spontaneous healing (SH), vehicle ointment (V), vehicle ointment + rhEGF at concentrations of 1 μg/g (EGF1), 10 μg/g (EGF10) or 50 μg/g (EGF50). Topical administration of ointments was repeated twice per day until sacrifice at days 8 and 16. Wound area was clinically monitored. Keratinocytes proliferation (Ki67-immunolabelling), inflammatory response (IR) and areas of collagen (C) and granulation tissue (GT) were histologically measured. Kruskal-Wallis test with Dunnett correction was used for multiple group statistical comparisons. RESULTS Clinically, in comparison with SH, a significantly smaller wound area was observed in groups EGF1 and EGF10 at day 8 (p

Background This experimental study aims to evaluate the effect of hyaluronic acid on healing of infected extraction sockets compared with recombinant human bone morphogenetic protein-2 (rhBMP-2). Methods Both third and fourth mandibular premolars of six beagle dogs were hemisected, and the distal roots were extracted at baseline. Subsequently, combined endodontic-periodontic lesions were induced at the remaining mesial roots. After 4 months, the mesial roots on both sides of the mandible were removed. Four sockets per dog were randomly allocated to four groups: Group 1, Control; Group 2, only absorbable collagen sponge (ACS: carrier); Group 3, 1% hyaluronic acid (HA) gel + ACS; and Group 4, rhBMP-2 + ACS. After 3 months of healing, the dogs were euthanized for microcomputed tomography and histologic analysis. Results After the lesion induction period (4 months), communication between the periodontal lesion and endodontic periapical lesion was observed at all remaining mesial roots. Alveolar bone overgrowth was observed in groups 3 and 4, but bone volume density was not significantly different among all groups. At the crestal portion, mineralization, and osteocalcin expression were higher in groups 3 and 4 than in groups 1 and 2. Conclusion Treatment with HA can promote bone formation and improve the wound healing rate comparable to rhBMP-2 in infected extraction sockets.

Purpose To determine whether the swelling and mechanical properties of osmotic self-inflating expanders allow or not the induction of intraoral soft tissue expansion in dogs. Methods Three different volumes (0.15, 0.25, and 0.42 mL; referred to respectively as the S , M , and L groups) of soft tissue expanders (STEs) consisting of a hydrogel core coated with a silicone-perforated membrane were investigated in vitro to assess their swelling behavior (volume swelling ratio) and mechanical properties (tensile strength, tensile strain). For in vivo investigations, the STEs were subperiosteally inserted for 4 weeks in dogs (n=5). Soft tissue expansion was clinically monitored. Histological analyses included the examination of alveolar bone underneath the expanders and thickness measurements of the surrounding fibrous capsule. Results The volume swelling ratio of all STEs did not exceed 5.2. In tensile mode, the highest mean strain was registered for the L group (98.03±0.3 g/cm), whereas the lowest mean value was obtained in the S group (81.3±0.1 g/cm), which was a statistically significant difference (P

PURPOSE This systematic review aimed to identify the effects of certain flap management procedures on ridge preservation on the basis of existing literature. MATERIALS AND METHODS Electronic (MEDLINE, EMBASE, and Cochrane Central Register of controlled trials) and manual searches of the literature were conducted until February 2017. Randomized controlled trials (RCTs), controlled clinical trials (CCTs), and prospective cohort studies that involved at least 10 subjects were eligible for this systematic review. To evaluate the beneficial effects of flap management on ridge preservation, changes in the bone width, bone height, and keratinized gingiva width were calculated using a random effects model. RESULTS Eleven studies (nine RCTs and two CCTs) were included in this review. No statistically significant differences in bone width and height changes were identified between the flapped and flapless ridge preservation techniques and between the free gingival graft and flapless ridge preservation techniques. A statistically significant shrinkage in keratinized gingiva width was noted with flapped ridge preservation compared with flapless ridge preservation (weighted mean differences, -3.21 mm; 95% confidence interval, -4.10 to -2.33; P < .00001; heterogeneity, 51%; χ2, 0.15). CONCLUSION Within the limitations, this review reveals that flapless ridge preservation was more effective in preserving bone width, bone height, and keratinized gingiva width. To present pertinent evidence regarding which flap management should be recommended for ridge preservation, more controlled and high-quality studies are warranted.

Objective: This review aimed to investigate the feasibility of immediate implant placement in infected extraction sockets. Material and methods: We performed electronic and manual searches up to March 2017 to obtain data from randomized controlled trials (RCTs) and nonrandomized controlled clinical trials (CCTs). Using a fixed-effects model to assess the difference in survival rate (primary outcome), we evaluated the risk difference for immediate implant placement in infected and non-infected sites. We estimated the weighted mean differences (WMDs) of the change in marginal bone loss (MBL), probing depth (PD), modified bleeding index (mBI), marginal gingival level (MGL) and width of keratinized gingiva (WKG) at baseline and latest follow-up. Results: In total, five studies (0 RCT, five CCTs) were included in the systematic review and three studies were included in the meta-analysis. The risk difference for immediate implant placement in an infected extraction socket compared with that in a non-infected socket was −0.02. WMDs for MBL, PD, mBI, MGL and WKG between the two groups were 0.32, 0.12, 0.07, −0.06, 0.20 and 0.51, respectively. No statistical differences were observed between the two groups, except for the change in WKG. Conclusions: Implants can be placed in infected extraction sockets after thorough socket debridement. For aesthetics, WKG should be considered when performing immediate implant placement in infected sites.

Various studies have investigated 3-dimensional (3D)-printed implants using Ti-6Al-4V powder; however, multi-root 3D-printed implants have not been fully investigated. The purpose of this study was to explore the stability of multirooted 3D-printed implants with lattice and solid structures. The secondary outcomes were comparisons between the 2 types of 3D-printed implants in micro-computed tomographic and histological analyses.Lattice- and solid-type 3D-printed implants for the left and right mandibular third premolars in beagle dogs were fabricated. Four implants in each group were placed immediately following tooth extraction. Implant stability measurement and periapical X-rays were performed every 2 weeks for 12 weeks. Peri-implant bone volume/tissue volume (BV/TV) and bone mineral density (BMD) were measured by micro-computed tomography. Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) were measured in histomorphometric analyses.All 4 lattice-type 3D-printed implants survived. Three solid-type 3D-printed implants were removed before the planned sacrifice date due to implant mobility. A slight, gradual increase in implant stability values from implant surgery to 4 weeks after surgery was observed in the lattice-type 3D-printed implants. The marginal bone change of the surviving solid-type 3D-printed implant was approximately 5 mm, whereas the value was approximately 2 mm in the lattice-type 3D-printed implants. BV/TV and BMD in the lattice type 3D-printed implants were similar to those in the surviving solid-type implant. However, BIC and BAFO were lower in the surviving solid-type 3D-printed implant than in the lattice-type 3D-printed implants.Within the limits of this preclinical study, 3D-printed implants of double-rooted teeth showed high primary stability. However, 3D-printed implants with interlocking structures such as lattices might provide high secondary stability and successful osseointegration.

The role of hard-type crosslinked hyaluronic acid (HA) with particulate bone substitutes in bone regeneration for combined inlay-onlay grafts has not been fully investigated. We aimed to evaluate the effect of hard-type crosslinked HA used with bone substitute in terms of new bone formation and space maintenance.A 15-mm-diameter round defect was formed in the calvaria of 30 New Zealand White rabbits. All animals were randomly assigned to 1 of 3 groups: the control group (spontaneous healing without material, n=10), the biphasic calcium phosphate (BCP) graft group (BCP, n=10), and the BCP graft with HA group (BCP/HA, n=10). The animals were evaluated 4 and 12 weeks after surgery. Half of the animals from each group were sacrificed at 4 and 12 weeks after surgery. Samples were evaluated using micro-computed tomography, histology, and histomorphometry.The BCP group showed higher bone volume/tissue volume (BV/TV) values than the control and BCP/HA groups at both 4 and 12 weeks. The BCP and BCP/HA groups showed higher bone surface/tissue volume (BS/TV) values than the control group at both 4 and 12 weeks. The BCP group showed higher BS/TV values than the control and BCP/HA groups at both 4 and 12 weeks. No statistically significant difference in newly formed bone was found among the 3 groups at 4 weeks. The BCP group showed significantly higher new bone formation than the BCP/HA group at 12 weeks.Hard-type crosslinked HA did not show a positive effect on new bone formation and space maintenance. The negative effect of hard-type crosslinked HA may be due to the physical properties of HA that impede osteogenic potential.

Purpose The purpose of this study was to investigate the feasibility of regenerative therapy with a collagenated bone graft and resorbable membrane in intrabony defects, and to evaluate the effects of the novel extracellular matrix (ECM)-based membrane clinically and radiologically. Methods Periodontal tissue regeneration procedure was performed using an ECM-based resorbable membrane in combination with a collagenated bovine bone graft in intrabony defects around the teeth and implants. A novel extracellular matrix membrane (NEM) and a widely-used membrane (WEM) were randomly applied to the test group and the control group, respectively. Cone-beam computed tomography images were obtained on the day of surgery and 6 months after the procedure. Alginate impressions were taken and plaster models were made 1 week and 6 months postoperatively. Results The quantity of bone tissue, the dimensional changes of the surgically treated intrabony defects, and the changes in width and height below the grafted bone substitutes showed no significant difference between the test and control groups at the 6-month examination. Conclusions The use of NEM for periodontal regeneration with a collagenated bovine bone graft showed similar clinical and radiologic results to those obtained using WEM., Graphical Abstract

Purpose The aim of this prospective pilot study was to compare alveolar ridge preservation (ARP) procedures with open-healing approach using a single-layer and a double-layer coverage with collagen membranes using radiographic and clinical analyses. Methods Eleven molars from 9 healthy patients requiring extraction of the maxillary or mandibular posterior teeth were included and allocated into 2 groups. After tooth extraction, deproteinized bovine bone mineral mixed with 10% collagen was grafted into the socket and covered either with a double-layer of resorbable non-cross-linked collagen membranes (DL group, n=6) or with a single-layer (SL group, n=5). Primary closure was not obtained. Cone-beam computed tomography images were taken immediately after the ARP procedure and after a healing period of 4 months before implant placement. Radiographic measurements were made of the width and height changes of the alveolar ridge. Results All sites healed without any complications, and dental implants were placed at all operated sites with acceptable initial stability. The measurements showed that the reductions in width at the level 1 mm apical from the alveolar crest (including the bone graft) were −1.7±0.5 mm in the SL group and −1.8±0.4 mm in the DL group, and the horizontal changes in the other areas were also similar in the DL and SL groups. The reductions in height were also comparable between groups. Conclusions Within the limitations of this study, single-layer and double-layer coverage with collagen membranes after ARP failed to show substantial differences in the preservation of horizontal or vertical dimensions or in clinical healing. Thus, both approaches seem to be suitable for open-healing ridge preservation procedures., Graphical Abstract

Purpose The aim of this study was to radiographically and clinically compare the effect of extracellular matrix (ECM) membranes on dimensional alterations following a ridge preservation procedure. Methods One of 2 different ECM membranes was applied during a ridge preservation procedure. A widely used ECM membrane (WEM; Bio-Gide, Geistlich Biomaterials, Wolhusen, Switzerland) was applied in the treatment group and a newly developed ECM membrane (NEM; Lyso-Gide, Oscotec Inc., Seongnam, Korea) was applied in the control group. Cone-beam computed tomography (CBCT) scans and alginate impressions were obtained 1 week and 6 months after the ridge preservation procedure. Results were analyzed using the independent t-test and the nonparametric Mann-Whitney U test. Results There were no significant differences between the ECM membranes in the changes in the dimension, width, and height of the extraction socket or the quantity of bone tissue. Conclusions The NEM showed comparable clinical and radiographic results to the WEM following the ridge preservation procedure., Graphical Abstract

Purpose: Avoiding excessive trauma-thermal or otherwise-during dental implant site preparation is considered critical to implant success; overheating is considered to be a major cause of bone necrosis. Studies evaluating thermal and mechanical effects of implant drill design are limited, and effects of flute design have not been accounted for. The purpose of this study was to compare heat generation and cutting efficiency associated with two-, three-, and four-fluted implant drills to investigate the optimal number of flutes. Materials and Methods: Two-, three-, and four-fluted dental implant drills with identical point, relief, and rake angles and otherwise standard dimensions were evaluated. Real-time temperature changes while drilling artificial bone were recorded using an infrared thermal imager. Cutting efficiency was assessed as the drilling time to a 15-mm depth under constant load using a specially designed recording system. Each drill variation was examined 20 times. A one-way analysis of variance was used for statistical analysis. Results: Mean temperature increases amounted to 8.3°C, 10.8°C, and 15.1°C for two-, three-, and four-fluted drills, respectively; temperatures significantly increased (P < .001) with an increased number of flutes. Mean drilling time serving as a measure of cutting efficiency amounted to 2.6, 2.5, and 2.5 seconds for the two-, three-, and four-fluted drills, respectively. A trend of cutting efficiency increasing or decreasing according to the number of flutes was not observed. Differences in cutting efficiency among the three drill variations were statistically significant (P = .015). The cutting efficiency of the three-fluted drill was superior to that of the two-fluted drill (P = .016). Conclusion: Within the limitations of the study, a two-fluted drill would be preferred for osteotomy preparation due to its level of heat generation, whereas a three-fluted drill showed favorable cutting efficiency.

BACKGROUND: Trichloroacetic acid (TCA) is an agent widely applied in dermatology for skin regeneration. To test whether TCA can offer an advantage for the regeneration of oral soft tissue defects, the cellular events following TCA application were explored in vitro and its influence on the oral soft tissue wound healing was evaluated in a canine palate model. METHODS: The cytotoxicity and growth factor gene expression in human gingival fibroblasts were tested in vitro following the application of TCA at four concentrations (0.005%, 0.05%, 0.5% and 1%) with different time intervals (0, 3, 9 and 21 h). One concentration of TCA was selected to screen the genes differentially expressed using DNA microarray and the associated pathways were explored. TCA was injected in open wound defects of the palatal mucosa from beagle dogs (n = 3) to monitor their healing and regeneration up to day 16-post-administration. RESULTS: While the 0.5–1% concentration induced the cytoxicity, a significantly higher expression of growth factor genes was observed after 3 and 9 h following the 0.5% TCA application in comparison to other groups. DNA microarray analysis in 0.5% TCA group showed 417 genes with a significant 1.5-fold differential expression, involving pathways of cell cycle, FoxO signaling, p53 signaling, ubiquitin mediated proteolysis and cAMP signaling. In vivo results showed a faster reepithelialization of TCA-treated wounds as compared to spontaneous healing. CONCLUSION: TCA promoted the healing and regeneration of oral soft tissue wound defects by up-regulating the cell cycle progression, cell growth, and cell viability, particularly at a concentration of 0.5%. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13770-019-00227-6) contains supplementary material, which is available to authorized users.

AIM To determine the effect of alveolar ridge preservation (ARP) in molar sites without primary flap closure. MATERIALS AND METHODS Three groups were established: extraction sockets grafted with deproteinized bovine bone mineral containing 10% collagen (DBBM-C) and covered by a native bilayer collagen membrane (NBCM) (test group 1), sockets grafted with DBBM-C only (test group 2), and sockets that healed naturally (control group). Primary flap closure was not attempted. Conebeam computed tomography scans were obtained immediately and then 4 months after ARP. A biopsy was performed. The change of the marginal bone level was measured. RESULTS There was significantly less horizontal resorption in test group 1 than in the control group at levels 1 mm (-1.02 ± 0.88 [mean ± SD] vs. -4.44 ± 3.71 mm) and 3 mm (-0.31 ± 1.51 vs. -2.27 ± 1.15 mm) below the crest, and significantly less vertical reduction in the midcrestal area in test group 1 than in test group 2 (-0.25 ± 0.95 vs. -1.15 ± 1.63 mm) (p

BACKGROUND The data on the importance of soft-tissue management during surgical treatment of periimplantitis are still limited, and no clinical recommendations are yet available. AIM To give an overview on the rationale for periimplant soft-tissue augmentation procedures in the light of potential benefits/risks of the presence/absence of keratinized/attached mucosa (KAM) providing recommendations for the clinician. RESULTS The available evidence indicates that the presence of KAM favors periimplant tissue health evidenced by improved bleeding scores and facilitation of self-performed plaque removal, less mucosal recessions, and more stable marginal bone levels over time. Therefore, the rationales to augment KAM are (a) to optimize the possibility for performing an adequate level of oral hygiene, (b) to help maintaining periimplant soft-tissue health and stability, and (c) to improve esthetics. Various techniques with autogenous or xenogeneic membranes have been described so far for KAM augmentation. Additional soft-tissue grafting in conjunction with a combined regenerative and resective surgical procedure seems to be effective in treating and controlling advanced periimplantitis lesions and improving or maintaining the esthetic outcomes. CONCLUSIONS The limited available data seem to indicate that the best outcome to improve the width of KAM, and the bleeding and plaque scores, as well as to maintain the periimplant marginal bone level is the use of an apically positioned flap combined with a free gingival graft in nondiseased periimplant sites. However, at present, it is unknown: (a) to what extent soft-tissue grafting may additionally improve the outcomes after surgical (resective or regenerative) treatment of periimplantitis compared with the same approaches without soft-tissue grafting, and (b) if considered, when should soft-tissue grafting be performed (eg, before or during surgical treatment of periimplantitis). CLINICAL RECOMMENDATIONS Both soft-tissue resective and regenerative approaches may lead to successful outcomes depending on the clinical indication and defect location. However, the selection of one or another surgical approach should be based on defect type (eg, intrabony and suprabony) and location (esthetic or nonesthetic areas). The presence of an adequate width and thickness of KAM may facilitate soft-tissue (flap) management. In patients with a thin phenotype or lack of an adequate width of KAM, soft-tissue grafting may improve the clinical outcomes.