Correction to: Influence of surface treatment on osseointegration of dental implants: histological, histomorphometric and radiological analysis in vivo.

Dear Professor Dr. Matthias Hannig. Editor-in-Chief Clinical Oral Investigations. Following the publication of our paper by Calvo Guirado et al, 2015 [1] in Clinical Oral Investigations, it came to light that a certain part of the text at the materials and methods and results sections were similar.

Biological effects of compressive forces exerted on particulate bone grafts during socket preservation: animal study.

OBJECTIVES: To compare different compressive forces exerted on a particulate graft material during socket preservation and their effects on bone regeneration. MATERIAL AND METHODS: Six male dogs were used. The second, third, and fourth premolars, and the first molar were extracted bilaterally at the lower jaws. A particulate synthetic biphasic grafting material (60% HA and 40% ß-tricalcium phosphate) was used. Three different standardized compressive forces were applied randomly during the socket preservation. The sample was divided into four experimental groups Test A (10 g), Test B (50 g), Test C (200 g), and Control (empty sockets). Collagen membranes were placed, and primary closure was obtained. Two months after the surgery the animals were sacrificed, and histomorphometric analysis of non-decalcified samples was performed at the coronal, middle, and apical thirds. RESULTS: Grafted sockets resulted in higher bony contour (3 ± 0.43 mm2 ; P < 0.05). The particles penetrated up to the apical third in the group C but not in the other test groups and controls (P < 0.05). The percentage of new bone were higher at the coronal and apical thirds for Controls and group C compared to A and B groups (P < 0.05). The residual graft was higher for group C (53 ± 1.4%), followed by group B (45 ± 3.1%) and group A (35 ± 1.9%; P < 0.05). The percentages of connective tissue were higher at the middle third without differences between groups (P > 0.05). CONCLUSIONS: Within the limitations of this experimental animal study, it might be concluded that grafted sockets compressed with 200 g force will have higher bony contours; higher compressive forces facilitate the penetration of the particulate graft material into the apical area of the socket and results in more bone formation at the coronal, middle, and apical thirds.

The influence of drill length and irrigation system on heat production during osteotomy preparation for dental implants: an ex vivo study.

OBJECTIVE: This study aimed to measure the influence of drill length and irrigation system on heat production during osteotomy preparation for dental implants using bovine bone rib as experimental model. MATERIALS AND METHODS: Three groups were created: Group 1: drilling with three consecutive burs with double irrigation (internal and external) for a 4.0 mm conical implant; and Group 2 and Group 3: drilling with three consecutive burs with external irrigation for a 4.1 mm cylindrical implant and for a 4.3 mm conical implant, respectively. Four lengths were tested: 10, 12, 14 and 16 mm; in site prepared on bovine ribs using a surgical unit linked to a testing device, to standardize and simulate implant drilling procedures. Bone temperature variations were recorded using three thermocouples in different positions as of the crestal bone: 2 mm, position (p1); 7 mm, position 2 (p2); and 12 mm, position 3 (p3). RESULTS: The highest temperature changes were invariably recorded during the process of withdrawal. Significantly lower temperature changes (P < 0.02) could be recorded at maximum drilling depths during the shearing process regardless of drilling depth or irrigation method. Double irrigation was associated with significantly lower temperatures compared with external irrigation by the use of implant drills (P < 0.01). CONCLUSIONS: Within the limitations of this ex vivo study was possible concluded that the use a double irrigation system in multiple conventional drill for osteotomy can decrease the heat generation when increase the drill length.

Peri-implant bone loss clinical and radiographic evaluation around rough neck and microthread implants: a 5-year study.

OBJECTIVE: To evaluate marginal bone loss over 5 years around microthreaded implants placed in the maxillary anterior/esthetic zone and immediate restored with non-occlusal loading. MATERIALS AND METHODS: Seventy-one implants (with microthreads up to the platform-rough surface body and neck, internal connection and platform switching) were placed in healed bone in the maxillary arches of 30 men and 23 women (mean age 37.85 ± 7.09 years, range 27-60). All subjects had at least 3 mm of soft tissue to allow the establishment of adequate biologic width and to reduce bone resorption. Each patient received a provisional restoration immediately after implant placement with slight occlusal contact. Mesial and distal bone height was evaluated using digital radiography on the day following implant placement (baseline) and after 1, 2, 3, 4 and 5 years. Primary stability was measured with resonance frequency analysis. RESULTS: No implants failed, resulting in a cumulative survival rate of 100% after 3 years. Marginal bone loss from implant collar to bone crest measured at baseline (peri-implant bone defect at the fresh extraction socket) and after 5 years was 0.90 mm ± 0.26 mm. Mesial and distal site crestal bone loss ranged from 3.42 ± 1.2 mm at baseline to 3.51 ± 1.5 mm after 5 years and from 3.38 ± 0.9 mm at baseline to 3.49 ± 0.9 mm after 5 years, respectively (P = 0.086). CONCLUSIONS: The results of this study showed limited implant crestal bone loss 0.90 mm ± 0.26 mm and 100% of implant survival rate at 5-year follow-up of immediate restored implants with rough surface neck and microthreads.

Influence of hydroxyapatite granule size, porosity, and crystallinity on tissue reaction in vivo. Part B: a comparative study with biphasic synthetic biomaterials.

OBJECTIVE: The aim of this study was to compare the influence of the physical-chemical properties of synthetic hydroxyapatite (HA) and biphasic commercial materials on the biological behavior of study materials through material characterization and SEM analysis before and after application in rabbit tibias. MATERIALS AND METHODS: Two defects were performed in each tibiae for a total of 180 defects: Group I HA granules (2000-4000 µm), Group II HA granules (1000-2000 µm), Group III HA granules (600-1000 µm), Group IV Ossceram® nano (Bredent medical GmbH & Co. KG, Senden, Germany), Group V 4Bone® granules (MIS Implants Technologies Ltd, Shlomi, Israel), and Group VI: empty defect acted as control. Comparison was performed by mean of material characterization, SEM, and EDX. RESULTS: 4Bone: Pores between 300 µm and 100 µm with intra- and interparticle spaces. Ossceram show also interparticle and intraparticle pores, between 100 µm and 26 µm, but the proportion of interparticles in the 4Bone is clearly minor than in the Ossceram. Related with pure HA, Group III has the greatest porosity (69.3%). For Group I, the intraparticle pores (0.71 µm) are about 8 times larger than those of the other two samples. The analysis of the images of in vivo SEM shown as biphasic groups has presented a more gradual resorption of the material. CONCLUSION: HA-based biomaterials, both pure and biphasic, are an effective means for bone regeneration processes; of these, materials with higher initial and secondary porosimetry allow greater cell colonization and therefore more effective substitution by new bone. The two-phase materials have a higher ion release to the environment in the early stages and thus allow greater colonization by collagen fibers that can be matured into new bone.

Effects on the osseointegration of titanium implants incorporating calcium-magnesium: a resonance frequency and histomorphometric analysis in rabbit tibia.

OBJECTIVE: This study assessed the bone formation around titanium surface incorporating the calcium-magnesium (CaMg) deposited by blasted in rabbit tibia bone to determine whether this surface would further enhance bone healing compared with commercially available implant surface. MATERIAL AND METHODS: The deposition of CaMg on the titanium SLA surface were obtained by blasting formed the experimental group (EX group), while implants with traditional SLA surface were used as control group (CO group), in this study. Fifty cylindrical threaded implants with a length of 8 mm were used (P = 25 per group). Five implants of each group were used to surface characterization by scanning electron microscopy, energy dispersive spectrometry, and optical profilometry. Ten New Zealand white rabbits received 40 implants (n = 20 per group). Resonance frequency analysis was performed three times (0, 4, and 6 weeks). Histomorphometric analysis was performed 4 and 6 weeks after implantation. Statistical significance was set at P < 0.05. RESULTS: Blasted CaMg deposition on SLA implant surface displayed almost identical surface morphologies and R(a) values at the micron scale. In comparing the implant stability quotient at the three time points, highly significant statistic differences were found (P < 0.001). Histomorphological analysis showed higher degrees of bone organization in the samples of test implant surfaces at both implantation times. CONCLUSION: Within the limitations of this study, the results indicate that the deposition of CaMg on the SLA titanium surface may be effective in enhancing the osseointegration of moderately rough grit-blasted implants by increasing the degree of bone-implant contact.

Evaluation of extrashort 4-mm implants in mandibular edentulous patients with reduced bone height in comparison with standard implants: a 12-month results.

OBJECTIVE: The aim of this research was to evaluate the primary stability, the marginal bone loss, the survival, and the success criteria, of 4-mm-length implants compared with implants of conventional length supporting fixed prostheses. MATERIALS AND METHODS: Ten patients were selected for treatment of their atrophic edentulous jaws. Each patient received the following treatment: six dental implants were inserted, two anterior implants of conventional length (10-mm) in the interforaminal area and four posterior short implants of 4-mm length (Standard Plus, Roxolid, SLActive, Institut Straumann AG). The implants supported screw-retained fixed complete dentures. Examinations were conducted at day 0, three, six, and twelve months after surgery for the evaluation of the implant primary stability, secondary stability, crestal bone loss and survival by clinical evaluations, insertion torque values, resonance frequency analysis (RFA), and periapical radiography, respectively. RESULTS: Sixty implants were inserted in ten patients. Mean insertion torque was slightly lower for 4-mm implants than 10-mm implants (38.1 Ncm vs. 42.2 Ncm) but without statistically significant difference. Implant stability was similar for extrashort and conventional implants. Marginal bone loss was similar for both groups for all the time periods. One short implant was lost before loading. The survival rates twelve months after implant placement were of 97.5% and 100% for short and conventional implants, respectively. Similarly, implant stability as measured by RFA was nonsignificantly lower for the 4-mm implants compared to the 10-mm implants. The marginal bone loss was lower for short implants three, six, and twelve months after the surgery without statistical significant difference. CONCLUSIONS: Within the limitations of this study, we conclude that short dental implants (8 mm or less in length) supporting single crowns or fixed bridges are a feasible treatment option with radiographic and clinical success rates similar to longer implants for patients with compromised ridges. Long-term data with larger number of implants and subjects are needed to confirm these preliminary results.

Histological and histomorphometric analyses of narrow implants, crestal and subcrestally placed in severe alveolar atrophy: a study in foxhound dogs.

BACKGROUND: Narrow-diameter implants provide an alternative to the horizontal augmentation techniques situations severe bone atrophy. Lack of bone width and interdental space has been regarded as an encumbrance in the case selection for prosthetic rehabilitation using dental implants. OBJECTIVE: The aim of the study was to evaluate bone-to-implant contact and marginal bone loss of two different narrow implants in resorbed ridges at different crestal positions. MATERIAL AND METHODS: 48 Bredent Narrow(®) implants (24 MiniSky(®) and NarowSky(®) ) were placed at crestal and subcrestal levels in healing bone of atrophic alveolar ridge of 6 American foxhounds. Histological and histomorphometric analyses of osseointegration were carried out at 4 and 8 weeks. RESULTS: Modeling in the marginal defect region was accompanied by marked decreases in the dimensions of both the buccal and the more lingual bone walls. Relative to BIC, significant differences were found in favor of subcrestal group, for both Narrow Sky and MiniSky. Linear measurements showed to be slightly high in the crestal group. With significant differences for PM-IS (peri-implant mucosa to implant shoulder) and IS-BC (implant shoulder to buccal bone crest). CONCLUSIONS: Within the limitations of animal study, it can be stated that the NarrowSky(test group) crestal and subcrestal implants showed less crestal bone resorption, higher ISQ values and most BIC at 4 and 8 weeks of evaluation compared with MiniSky implants (control group). The design of the implants plays an important role in peri-implant mucosa and crestal bone maintenance at 8-week follow-up period.

Retracted: In vivo behavior of hydroxyapatite/ß­TCP /collagen scaffold in animal model. Histological, histomorphometrical, radiological, and SEM analysis at 15, 30, and 60 days

Retraction: Maté Sánchez de Val JE , Calvo Guirado JL , Ramírez Fernández MP , Delgado Ruiz RA , Mazón P, De Aza PN . In vivo behavior of hydroxyapatite/ß­TCP /collagen scaffold in animal model. Histological, histomorphometrical, radiological, and SEM analysis at 15, 30, and 60 days. Clin Oral Impl Res . The above article, published online on August 7, 2015, in Wiley Online Library (wileyonlinelibrary.com) has been retracted by agreement between the journal editor­in­chief, L Heitz­Mayfield, and John Wiley & Sons Ltd. The retraction has been agreed due to image discrepancies resulting in unreliable data. It has not been possible to prove the validity of the images. Images in Figure 4 have been used in other publications representing different time points and materials. Images within Figure 4 have been manipulated to represent different time points and materials. Reference Maté Sánchez de Val JE , Calvo Guirado JL , Ramírez Fernández MP , Delgado Ruiz RA , Mazón P, De Aza PN . In vivo behavior of hydroxyapatite/ß­TCP /collagen scaffold in animal model. Histological, histomorphometrical, radiological, and SEM analysis at 15, 30, and 60 days. Clin Oral Impl Res . https://doi.org/10.1111/clr.12656

Influence of collar design on peri-implant tissue healing around immediate implants: A pilot study in Foxhound dogs.

PURPOSE: The study aims to assess the soft tissue level (STL) and crestal bone level (CBL), of titanium dental implants with different mixed collar abutments configurations. MATERIALS AND METHODS: This study included 48 implants with the same dimensions. They were divided into two groups of 24 implants each one: implants with a polished collar of 2 mm plus a roughened area of 0.8 mm (CONTROL) and implants with a polished collar of 0.8 mm plus a micro-threated and roughened area of 2 mm (TEST). The implants were inserted randomly in the post-extraction sockets of P2, P3, P4, and M1 bilaterally in the lower jaw of six foxhound dogs. STL and CBL were evaluated after 8 and 12 weeks by histology and histometry. RESULTS: All implants were clinically and histologically osseointegrated. Healing patterns examined microscopically at 8 and 12 weeks for both groups yielded similar qualitative findings for the STL evaluation, without significant differences between groups (P > 0.05). CBL was significantly higher in the buccal side in comparison with the lingual side for both groups (P < 0.05); the comparison between groups at 8 weeks showed IS-B (distance from the implant shoulder to the top of the bony crest) and IS-C (distance from the implant shoulder to the first bone-to-implant contact) values significantly higher for control group in comparison with test (P < 0.05). At 12 weeks, CBL showed increased values for both groups that were higher in controls group in comparison with test (P < 0.05). CONCLUSIONS: Bony crest resorption could not be avoided both at test and control sites. However, the neck conformation at the test sites reduced the buccal bone resorption. Soft tissue dimensions were similar both at the test and control sites.

Biological width formation to immediate implants placed at different level in relation to the crestal bone: an experimental study in dogs.

PURPOSE/AIM: Evaluate differences in bone remodeling, soft tissue reactions and biological width formation around immediate implants placed at different level in relation to the crestal bone in beagle dogs. MATERIAL AND METHODS: The mandibular second, third and fourth premolars of six beagle dogs were extracted, and three implants were placed in the right side of each dog. Healing abutments were adjusted (n = 18). After 4 weeks, the procedure was repeated on the left side of the mandible (n = 18). Randomly, three implants were placed at crestal level (control group), and three implants were placed 2 mm subcrestally (test group) in relation to the crestal bone in each animal. The dogs were sacrificed after 8 weeks from the first surgical procedure, and biopsies were obtained. Samples were processed for ground sectioning. Histometric analysis was carried out to compare buccal and lingual bone resorption, soft tissue behavior and biological width formation in both groups. RESULTS: Crestal bone resorption was higher in the test group when considering the difference of 2 mms (IS-B = 2.05 ± 0.36 mm, control; 1.75 (+2) ± 0.38 mm, test). However, the dimensions of the biological width were similar for both groups (PM-C = 3.34 ± 0.53 mm, control; 3.13 ± 0.55 mm, test). CONCLUSIONS: The alterations that occurred in the peri-implant soft tissues may be related to the hard tissue remodeling, showing similar quantitative findings in the biological width formation in both groups. Even though the subcrestal placement might reduce the distance from the implant shoulder to the first bone-to-implant contact and reestablish the biological width dimension in a most coronal position, it might not have any effect on minimizing the marginal bone loss.

Bone remodeling at implants with different configurations and placed immediately at different depth into extraction sockets. Experimental study in dogs.

OBJECTIVES: This study evaluated the effect of implant macrodesign and position, related to the bone crest, on bone-to-implant contact (BIC) and crestal bone (CB) in immediate implants. MATERIAL AND METHODS: The study comprised of six foxhound dogs in which 48 immediate implants were placed. Three types of implants from the same manufacturer with similar surface characteristics but different macrodesigns were randomly placed: Group A (external hex with no collar microthreads), Group B (internal hex and collar microrings), and Group C (internal conical connection and collar microrings). Half of the implants were placed leveled with the bone crest (control) and the remaining, 2 mm subcrestally (test). Block sections were obtained after 12 weeks and processed for mineralized ground sectioning. Statistical analysis consisted of nonparametric Friedman and Wilcoxon test. RESULTS: All implants were clinically stable and histologically osseointegrated. Mean BIC percentage within the control group was as follows: A: 42.52 ± 8.67, B: 35.19 ± 18.12, and C: 47.46 ± 11.50. Within the test group: A: 47.33 ± 5.23, B: 48.38 ± 11.63, and C: 54.88 ± 11.73. Differences between each subgroup in the test and the control groups were statistically significant. BIC was statistically significantly higher in the test (50.588 ± 8.663) than in the control (43.317 ± 9.851) group. Within both groups, differences between group C and the other 2 were statistically significant. Distance from the implant shoulder to the buccal CB was statistically significantly larger in the control than in the test group and between subgroups B and C in the control and test groups. Within the test groups, relative bone gain was noticed. CONCLUSIONS: Subcrestal immediate implant positioning may lead to a relatively reduced CB resorption and increased BIC. Implants macrodesign with crestal microrings may enhance BIC in post-extraction implants.

Influence of surface treatment on osseointegration of dental implants: histological, histomorphometric and radiological analysis in vivo.

OBJECTIVE: The aim of this article is to compare the influence of surface treatment on the integration (at 2, 4 and 8 weeks) of 120 dental implants inserted in 60 tibiae of rabbits. MATERIALS AND METHODS: Four different surfaces were double-blind tested: blasted, acid-etched and discrete crystal deposition (DCD) (group A); blasted (group B); acid-etched (group C) and blasted and acid-etched (group D). Bone-to-implant contact plus reverse torque and bone level were measured at the time of implant insertion and at 14, 28 and 56 days of healing. RESULTS: Group A showed the highest early and late bone-to-implant contact (BIC) values: 40.8 ± 2.3 % at 14 days decreasing to 27.7 ± 1.1 % after 28 days and 39.4 ± 1.4 % at 56 days. For group B, the average BIC values at 14, 28 and 56 days were 23.34 ± 2.1, 23.77 ± 1.9 and 29.47 ± 1.7 %, respectively. Group C showed a value of 25.72 ± 2.3 % after 14 days of integration, 34.92 ± 2.2 % at 28 days and 32.91 ± 1.6 % at 56 days. Group D showed a BIC value of 32 ± 2.5 % at 14 days, 32.85 ± 1.4 % at 28 days and 34.04 ± 2.3 % at 56 days. In the scanning electron microscopy (SEM) analysis, no statistically significant differences were found. The Ca/P ratio values were 1.762 for surface A, 1.625 for surface B, 1.663 for surface C and finally 1.722 for surface D. CONCLUSIONS: Therefore, we conclude that even if there seems to be a tendency to obtain better BIC results with surface A (blasted-etched and covered with hydroxyapatite (HA)), no statistical differences were obtained in this study. CLINICAL RELEVANCE: The study shows the influence of different implant surfaces in increasing osseointegation for immediate loading implants.

Histological, radiological and histomorphometric evaluation of immediate vs. non-immediate loading of a zirconia implant with surface treatment in a dog model.

OBJECTIVE: The aim of this study was to assess the performance of zirconia implants under immediate loading compared with delayed loading in dogs over 30-90 days. MATERIALS AND METHODS: Tooth extractions were made for the subsequent placement of dental implants at premolars P2, P3, P4 and molars M1 bilaterally in the dog mandible. Forty eight zirconia implants, 4 mm in diameter and 10 mm in length, were inserted, whose neck and body surfaces had been treated with femtosecond laser texturing; 24 implants were loaded immediately and 24 remained unloaded during the osseointegration period. Final radiographs were taken recording stability values before sacrifice at 30 or 90 days when sample removal for histological and histomorphometric analysis was performed. Bone-to-implant contact, crestal bone loss and implant stability were evaluated at these two study times. RESULTS: Bone-to-implant contact values after 30 days were 38.9% for immediately loaded implants and 32% for non-loaded implants. After 90 days, values increased to 65% for immediately loaded and 57.6% for non-loaded implants. After 30 days, there was more crestal bone lost in the non-loaded group (0.58 ± 0.28 mm) compared with the immediately loaded group (0.5 ± 0.3 mm). After 90 days, there was improved stability in both groups, but was lower in the immediately loaded group (0.5 ± 0.23 mm) compared with the non-loaded group (0.56 ± 0.28 mm). Initial implant stability values were -3.5 PTV at the moment of implant placement. Stability values after the first 30 days were -4 for immediately loaded implants and -3 for non-loaded. At 90 days, non-loaded implants showed -4.9, whereas immediately loaded showed -7.1. CONCLUSIONS: For the different parameters studied, zirconia implants treated with femtosecond laser and subjected to immediate loading showed better results compared with non-loaded implants in terms of BIC, crestal bone loss and implant stability.

Biomechanical and histological evaluation of four different titanium implant surface modifications: an experimental study in the rabbit tibia.

OBJECTIVES: This study presents a biomechanical comparison of bone response to commercially pure titanium screws with four different types of surface topographies placed in the tibial metaphysis of 30 rabbits. MATERIALS AND METHODS: One hundred twenty implants were tested double-blinded: (a) blasted, acid-etched, and discrete crystal deposition (DCD), (b) blasted, (c) acid-etched, and (d) blasted and acid-etch. Resonance frequency analysis (RFA/ISQ), reverse torque values (RTV), and bone-to-implant contact (BIC) were measured at the time of implant insertion (day 0), 15, 28, and 56 days of healing. RESULTS: All groups tested demonstrated increased RFA/ISQ and RTV results over the time course. At 15 days, the blasted, acid-etched, and DCD group demonstrated a non-significant trend toward higher values when compared to the blasted and etched group (33.0 ± 16 vs. 26.3 ± 12 Ncm, p = .16). At 56 days, the groups utilizing blasting to create additional surface roughness (Sa > 1 micron) showed a statistical significant difference in RTQ versus the non-blasted group (38.5 ± 14 vs. 29.5 ± 9 Ncm, p = .03). CONCLUSIONS: Within the limitations of this study, only the increase in surface roughness (Ra > 1) at 56 days demonstrated statistically significant effects on RTQ. Other additional surface features, such as sub-micron scale DCD, demonstrated improved healing trends but without significance for clinical applications.

Advances in Regenerative Dentistry: A Systematic Review of Harnessing Wnt/ß-Catenin in Dentin-Pulp Regeneration.

Dentin pulp has a complex function as a major unit in maintaining the vitality of teeth. In this sense, the Wnt/ß-Catenin pathway has a vital part in tooth development, maintenance, repair, and regeneration by controlling physiological activities such as growth, differentiation, and migration. This pathway consists of a network of proteins, such as Wnt signaling molecules, which interact with receptors of targeted cells and play a role in development and adult tissue homeostasis. The Wnt signals are specific spatiotemporally, suggesting its intricate mechanism in development, regulation, repair, and regeneration by the formation of tertiary dentin. This review provides an overview of the recent advances in the Wnt/ß-Catenin signaling pathway in dentin and pulp regeneration, how different proteins, molecules, and ligands influence this pathway, either upregulating or silencing it, and how it may be used in the future for clinical dentistry, in vital pulp therapy as an effective treatment for dental caries, as an alternative approach for root canal therapy, and to provide a path for therapeutic and regenerative dentistry.

Effectiveness of malic acid 1% in patients with xerostomia induced by antihypertensive drugs.

OBJECTIVES: Assessing the clinical effectiveness of a topical sialogogue on spray (malic acid, 1%) in the treatment of xerostomia induced by antihypertensive drugs. STUDY DESIGN: This research has been carried out through a randomized double-blind clinical trial. 45 patients suffering from hypertensive drugs-induced xerostomia were divided into 2 groups: the first group (25 patients) received a topical sialogogue on spray (malic acid, 1%) whereas the second group (20 patients) received a placebo. Both of them were administered on demand for 2 weeks. Dry Mouth Questionnaire (DMQ) was used in order to evaluate xerostomia levels before and after product/placebo application. Unstimulated and stimulated salivary flows rates, before and after application, were measured. All the statistical analyses were performed by using SPSS software v17.0. Different DMQ scores at the earliest and final stage of the trial were analysed by using Mann-Whitney U test, whereas Student's T-test was used to analyse salivary flows. Critical p-value was established at p<0.05. RESULTS: DMQ scores increased significantly (clinical recovery) from 1.21 to 3.36 points (p<0.05) after malic acid (1%) application whereas DMQ scores increased from 1.18 to 1.34 points (p>0.05) after placebo application. After two weeks of treatment with malic acid, unstimulated salivary flow increased from 0.17 to 0.242 mL/min whereas the stimulated one increased from 0.66 to 0.92 mL/min (p<0.05). After placebo application unstimulated flow ranged from 0.152 to 0.146 mL/min and stimulated flow increased from 0.67 to 0.70 mL/min (p>0.05). CONCLUSIONS: Malic acid 1% spray improved antihypertensive-induced xerostomia and stimulated the production of saliva.

Protein Adsorption, Calcium-Binding Ability, and Biocompatibility of Silver Nanoparticle-Loaded Polyvinyl Alcohol (PVA) Hydrogels Using Bone Marrow-Derived Mesenchymal Stem Cells.

Several approaches have evolved to facilitate the exploration of hydrogel systems in biomedical research. In this sense, poly(vinyl alcohol) (PVA) has been widely used in hydrogel (HG) fabrication for several therapeutic applications. The biological properties of PVA hydrogels (PVA-HGs) are highly dependent on their interaction with protein receptors and extracellular matrix (mainly calcium) deposition, for which there is not enough evidence from existing research yet. Thus, for the first time, the functional properties, like protein and mineral interactions, related to the proliferation of mesenchymal stem cells (MSCs) by silver nanoparticle (AgNP)-loaded PVA hydrogels (AgNPs-PVA-HGs) were investigated in the present study. The UV absorption spectrum and TEM microscopic results showed a maximum absorbance of synthesized AgNPs at 409 nm, with an average particle size of 14.5 ± 2.5 nm, respectively. The functional properties, such as the calcium-binding and the protein adsorption of PVA-HG, were accelerated by incorporating AgNPs; however, the swelling properties of the HGs were reduced by AgNPs, which might be due to the masking of the free functional groups (hydroxyl groups of PVA) by AgNPs. SEM images showed the presence of AgNPs with a more porous structure in the HGs. The proliferative effect of MSCs increased over culture time from day 1 to day 7, and the cell proliferative effect was upregulated by HGs with more pronounced AgNPs-PVA-HG. In addition, both HGs did not produce any significant cytotoxicity in the MSCs. The histological (bright light and H&E staining) and fluorescence microscopic images showed the presence of a cytoskeleton and the fibrillar structure of the MSCs, and the cells adhered more firmly to all HGs. More fibrillar bipolar and dense fibrillar structures were seen in the day 1 and day 7 cultures, respectively. Interestingly, the MSCs cultured on AgNPs-PVA-HG produced extracellular matrix deposition on day 7. Accordingly, the present results proved the biocompatibility of AgNPs-PVA-HG as a suitable system for culturing mammalian stem cells for regenerative tissue applications.