Calcium Phosphate Paste Research Articles

Remineralization potential of strontium-doped nano-hydroxyapatite dentifrice and casein phosphopeptide-amorphous calcium phosphate cream on white spot lesions in enamel following orthodontic debonding - a randomized controlled trial.

This study was intended to compare and determine the potency of strontium-doped nano-hydroxyapatite paste against a topical cream containing casein phosphopeptide-amorphous calcium phosphate and a regular dentifrice for remineralization of white spot lesions of enamel following orthodontic debonding. Ninety individuals with white spot lesions on their enamel who visited the orthodontic department for de-bonding were selected for the research. Patients were randomly assigned to three distinct groups with each group consisting of 30 patients. Group 1 served as the control and received regular dentifrice, Group 2 received strontium-doped nano-hydroxyapatite paste, and Group 3 received casein phosphopeptide-amorphous calcium phosphate topical cream. Patients were instructed to locally apply a specified amount of the prescribed preparation twice daily for six weeks. The data were analysed using the statistical programme SPSS 22.0 (SPSS Inc., Chicago, IL, USA), and the level of significance had been set at p < 0.05. Group 1 did not show any change in the enamel following the application of toothpaste. Both Group 2 and 3 demonstrated higher post-treatment scores, indicating effective remineralization potential (p < 0.001). However, Group 2 (strontium-doped nano-hydroxyapatite paste) displayed significantly greater remineralization capacity when compared to group 3 (casein phosphopeptide-amorphous calcium phosphate topical cream). Compared to conventional dentifrice and casein phosphopeptide-amorphous calcium phosphate paste, strontium-doped nano-hydroxyapatite preparation demonstrated greater enamel remineralization of the white spot lesions and favourable surface alterations in the enamel surface. strontium-doped nano-hydroxyapatite can be utilised safely and efficiently to treat early caries and remineralise white spot lesions on the enamel.

The Effect of Different Percentages of Nano-bioactive Glass in the Synthesized CPP/ACP Paste on the Remineralization of Demineralized Enamel

Background: The preventive treatments of primary caries lesions are essential for preventing destructive damage to the tooth structure. One of the common treatments is the application of casein phosphopeptide-amorphous calcium phosphate (CCP/ACP) paste on the enamel surface. The aim of this study was to investigate the effect of different percentages of nano-bioactive glass (nBG) incorporation into synthesized CPP/ACP paste on the remineralization of demineralized enamel. Methods: In general, 24 extracted human intact premolar teeth were selected, and their crowns were removed for this purpose. Each crown was cut into two halves, and each half was considered as a sample. The samples were placed in a demineralizing solution at a pH rate of 4.6 for 8 hours, in artificial saliva for 1 hour, and again in a remineralizing solution at a pH rate of 7 for 15 hours. The pH cycling was performed for 14 days to demineralize the enamel surface. The samples were randomly divided into 3 groups (n=16), including G1 (without treatment), G2 (treated with synthesized CPP/ ACP paste containing 5% nanobioglass), and G3 (treated with synthesized CPP/ACP paste containing 10% nanobioglass). The paste was then placed directly on the surface of the demineralized enamel for 4 minutes (twice a day for 28 days). The samples were subjected to the Vickers microhardness test. Finally, data were analyzed using SPSS (version 19) and the analysis of variance and Tukey’s tests (α = 0.05). Results: There was a significant difference between microhardness values in G1 and G2, as well as G1 and G3 (P&lt;0.05). However, no statistically significant difference was observed between G2 and G3 (P&gt;0.05). Conclusions: The results showed adding bioactive glass into synthetic CPP/ACP paste increases enamel remineralization in spite of the percentage of bioactive glass incorporation.

Penetration and durability of CPP-ACP paste and sodium fluoride varnish as desensitizing agents: An in vitro comparison.

This study aimed to investigate and compare the penetration and durability of two dentin desensitizers, sodium fluoride varnish and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste, using electron microscopy. The study was performed on 60 dentin specimens prepared from extracted human premolars. After applying 17% EDTA to remove the smear layer, the specimens were divided into two groups. MI Paste and Bi-fluoride varnish were applied to the specimens. Microscopic images of 20 samples were obtained immediately. Twenty other samples were accessed after 15 days, and the other 20 were accessed after 30 days of toothbrushing and thermal cycling. Both surface and longitudinal cross-sectional images (after sample fracture) were studied. Data were analyzed with two-way ANOVA and Mann-Whitney U test at a significance level of P<0.05. The mean depth of material penetration was significantly time-dependent and fluctuated in both groups. There was a significant difference between the mean level of plugs between 0, 15, and 30 days (P<0.001). Penetration increased with time for the MI Paste group, while in the Bi-fluoride group, the increase was significant at 15 and 30 days than immediately after application. The mean thickness of the plugs was significantly different at the three time periods, and MI Paste showed a sudden decrease in plug thickness after 15 days. Immediately after application, Bi-fluoride occluded dentinal tubules more effectively, and its durability after abrasion and thermal fatigue were higher than MI Paste.

Arthroscopic management of large subchondral talar cyst: a novel treatment strategy

Subchondroplasty is a novel and minimally invasive technique used to treat large subchondral talar cysts. It avoids soft tissue scarring, the need for osteotomies, bone grafting and its associated complications as seen with conventional approaches. Subchondroplasty involves arthroscopically approaching the cyst and injecting it with calcium phosphate paste injection, which undergoes an endothermic process and crystallizes in a manner that resembles cancellous bone to fill the defect. This case series presents two patients who underwent subchondroplasty: a 44-year-old female nurse with atraumatic right ankle pain of 2years with a CT scan revealing a large subchondral cyst over the medial talar dome and a 55-year-old male chemical plant worker with left ankle pain following a biking accident 6years ago whose CT scan too showed a large subchondral cyst in the medial talus. Both tolerated the surgery well, with significant reductions noted in MOXFQ scores at the 1-year follow-up.

Hardness analysis of remineralization primary teeth enamel after the application gel of duck eggshell extract (anas platyrhynchos domesticus) with consentration 20% and 40% in vitro

Background : Children are a population that has a high potential to be exposed to caries. Calcium deficiency due to demineralization of the enamel can cause a decrease in hardness during caries pathway. It can be anticipated with the application of re-mineralizing materials. Duck eggshells are contain high amount of calcium. This research aimed to examine the effect of duck eggshell extract gel (Anas plathyrhynchos domesticus) on the enamel hardness of primary teeth. Methods : This research is an experimental laboratory type using a pre and post-test control group design. There were 3 treatment groups with 4 samples in each group, which consisted of application of duck eggshell extract gel (Anas plathyrhynchos domesticus) with a concentration of 20% and 40%, and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste. Sample application was carried out 42 times in 14-day intervals. Then the sample was measured with vickers microhardness tester. The data were processed by using Paired T-Test, Kruskal-Wallis, and Post Hoc Mann-Whitney statistical tests. Results : showed that there were significant differences in the samples before and after the application of duck eggshell extract gel (Anas plathyrhynchos domesticus) (p&lt;0.05). Significant differences were also found in the three groups (p&lt;0.05). The group that experienced the highest increase in hardness was the 20% duck eggshell extract gel (Anas plathyrhynchos domesticus) treatment group. Conclusion : was that duck eggshell extract gel (Anas plathyrhynchos domesticus) with a concentration of 20% was effective in increasing the hardness of primary tooth enamel

APPLICATION OF CPP-ACP REMINERALIZATION MATERIALS (TOOTH MOUSSE) ON SALIVA PH IN STUDENT

Introduction: Dental and oral health is very important because it can affect the overall health of the body and affect the quality of life. Casein phosphopeptide-Amorphous calcium phosphate (CPP-ACP) is one of the ingredients used in dentistry to prevent caries. The degree of acidity of the pH of saliva is one of the factors that cause dental caries. The aim of the Research : To analyze the pH image of Saliva before and after the smearing of CPP-ACP (Tooth mousse) remineralization materials in 1st grade students of Anaka Elementary School tasikmalaya City. Type of Research: This research is a type of deskriphal research with a one group pre and post test research design design. The sampling technique is the total population, with a total sample of 34 respondents. Hasil saliva pH examination before and after being given the smearing treatment of CPP-ACP (Tooth mousse) remineralization material. Result of the Research: The results of salivary pH research before the smearing of antiangiogenic substances CPP-ACP (Tooth mousse) were at pH &lt; 7 as many as 34 people (100%) with an average pH of 6.00 in the "acid" category. While the pH of saliva after the smearing of anticariogenic material CPP-ACP (Tooth mousse) is the most at pH = 7 as many as 32 people (94.1%) pH &lt; 7 as many as 2 people with an average pH of 6.95 "neutral" category. Research Conclusion: That the use of Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) paste may increase salivary pH in the normal direction.

Artificial neural network investigation of injectability and percolation of highly filled β -Tricalcium phosphate suspensions

Over the past few decades, calcium phosphate cement has been used successfully for bone reconstruction applications. As percutaneous surgical methods have developed, there is an increased interest in calcium phosphate cement injection behavior. The aim of this study is to minimize percolation (liquid phase migration under pressure) and maximize injectability (ratio of the extruded part to whole) of highly filled β-tri calcium phosphate (β-TCP) suspensions by varying capillary flow process parameters with an artificial neural network (ANN) approach. The effects of hydroxyethyl cellulose (HEC) and polyethylene glycol (PEG-400) were also studied as binder additives for injectable β-tri calcium phosphate pastes. Prepared suspensions were investigated by capillary and small amplitude oscillatory rheometry. The study predicted experimental input and output data by using Backpropagation Neural networks via the Levenberg-Marquardt algorithm. The ANN model was developed by feed-forward back propagation network and predict percolation (%) and injectability (%). A great agreement was observed between the predicted values by the ANN model and the experimental data for injectability (%) and percolation (regression coefficients) of 0.9984 and 0.9982 respectively. The results depict that ANNs can improve the accuracy of injectability and percolation results which can be used to optimize process and additive parameters for injectable bone cements and pastes. 2 wt% HEC was determined as the most effective factor to improve the rheological properties of highly filled β-TCP pastes which could be injected as much as 99.21 % at a rate of 15 mm/min through dies with L/D ratio of 15. Their percolation value was calculated as 0.82 %. Lubricative effect of PEG-400 additive with 2 wt% HEC to reduce injection force was also demonstrated.

Analysis of the Role of CPP-ACPF Paste in Combination with Aqueous Extracts of Propolis to Improve Enamel Roughness after Demineralization Challenge

Aims: This study aims to evaluate the combined efficacy of aqueous extracts of propolis and Fluoridated Casein Phosphopeptide–Amorphous Calcium Phosphate (CPP.ACPF) paste or Minimal Intervention (MI) paste plus on improving enamel surface roughness after demineralization challenge. Materials and methods: A total of (75) posterior wisdom teeth were used in the study. Enamel blocks were prepared and divided into five groups randomly, the teeth in all groups were subjected to demineralization cycle and then treated with: Sinjar's aqueous extract of propolis (AEP)-MI paste plus cream n. (15), Sulaymaniah's AEP-MI paste plus cream n. (15), Duhok's AEP-MI paste plus cream group n. (15), control positive group of MI paste plus alone n. (15), and control negative group of artificial saliva alone n. (15). The Roughness of enamel blocks was measured using a profilometer machine at baseline, after demineralization cycle and finally after the treatment protocol.Results: There were statistically high significant differences among study groups after the demineralization cycle and there was an increase in surface roughness in all groups after demineralization, but the least elevation in surface roughness belonged to a mixture of Sulaymaniah's aqueous extract of propolis with MI past plus followed by Duhok's aqueous extract of propolis with MI past plus group after treatment protocol. Statistically, there were high significant reductions in surface roughness in all groups after the remineralization except in an artificial saliva group. Conclusions: Combination CPP-ACPF Paste with Aqueous Extracts of Propolis reducing enamel's roughness and increasingresistance to demineralization.

Influence of diode laser treatment and casein phosphopeptide-amorphous calcium phosphate paste on eroded root dentin.

It is still unclear whether the pretreatment for dentin hypersensitivity can interfere with the adhesive-dentin bonding strength. This study aimed to evaluate in vitro the effect of pretreatment with a casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste and diode laser on the shear bond strength of the etch-and-rinse adhesive system in the adhesive-dentin interface. Seventy-five bovine root specimens were randomly divided into five experimental groups (n = 15). Samples were eroded by six cycles of immersion in hydrochloric acid solution (0.01M; pH = 1.2) for 20 s each, at 45 min intervals, and treated with: G2 - no treatment, G3 - CPP-ACP, G4 - diode laser (970 nm), and G5 - CPP-ACP + Diode laser. After treatments, the morphology of the specimens was analyzed. The fracture mode of each group was evaluated after restoration with composite resins in the treated area. Data were analyzed by the one-way ANOVA and Tukey's test (P < 0.05). G3 showed the highest values for shear bond strength; there was no significant difference among G1, G3, and G5 (P > 0.05). The adhesive fracture was predominant for all groups. The use of desensitizers containing CPP-ACP, associated or not with a diode laser, increased the bond strength of the etch-and-rinse adhesive system on eroded root dentin.

The Effects of Casein Phosphopeptide-Amorphous Calcium Phosphate Paste and Tri-Calcium Phosphate Varnish in Preventing Enamel Demineralization: Roughness, Wettability, Ion-Selective Electrodes-Fluor and Hardness in Vitro

The Effects of Casein Phosphopeptide-Amorphous Calcium Phosphate Paste and Tri-Calcium Phosphate Varnish in Preventing Enamel Demineralization: Roughness, Wettability, Ion-Selective Electrodes-Fluor and Hardness in Vitro

Implications of unconventional setting conditions on the mechanical strength of synthetic bone grafts produced with self-hardening calcium phosphate pastes

This work presents the effects of several factors on the mechanical strength of a calcium phosphate cement (CPC) based on alpha tricalcium phosphate and correlates the results with the microstructure and percentage of conversion to hydroxyapatite. Conversion rate increased by raising the setting temperature in the studied range (4–90 °C), but the strength exhibited an increasing-decreasing trend due to changes in the morphology of hydrated crystals. Plate-like crystals were formed in the range of 22–60 °C, mechanically reinforcing the material, whereas the formation and refinement of needle-like crystals at higher setting temperature decreased the strength. Moreover, cements with dissimilar particle sizes had different optimal hydrolysis temperatures that resulted in the maximum strength. The finest powder led to higher strength at lower setting temperature due to the formation of a more compact crystal network and higher conversion. Therefore, optimization of powder particle size may allow to achieve the highest possible strength at room temperature, being beneficial for the production of the strongest pre-set CPC-based implants without the use of energy. Furthermore, the particle size can be also engineered to produce formulations that develop the highest strength at physiological temperature, with application as injectable bone grafts. The incorporation and crosslinking of gelatine further increased the mechanical strength of pre-set cements by bridging the hydroxyapatite crystals, the setting temperature showing a similar effect to that of gelatine-free cements. In contrast, moisture decreased the strength and reduced the brittleness by solvating intramolecular association between hydroxyapatite crystals and between gelatine molecules. Moreover, large cement bodies were slightly weaker than small ones, but the size effect was not statistically significant.

Antibacterial Efficacy of Casein Phosphopeptide-Amorphous Calcium Phosphate Compared to Calcium Hydroxide as Intracanal Medicaments against Enterococcus faecalis: In-vitro Study

Background: Endodontic infection may persist despite root canal instrumentation. Thus, the use of intracanal medicaments plays an essential role in eliminating resistant bacteria like Enterococcus faecalis, known to be associated with persistent infections in endodontically treated teeth. Although calcium hydroxide is the gold standard intracanal medicament, it has been reported that Enterococcus faecalis is immune to its effects. Therefore, several studies assessed the efficacy of other intracanal medicaments, but none to date evaluated Casein Phosphopeptide-Amorphous Calcium Phosphate. Objectives: This in-vitro randomized controlled study aimed to assess the antibacterial efficacy of Casein phosphopeptide-amorphous calcium phosphate as an intracanal medicament against Enterococcus faecalis and compared it to calcium hydroxide. Methods: 60 extracted single root canal permanent teeth were prepared and later divided into three equal groups according to the intracanal medicament used. Group 1: No intracanal medicament (negative control), Group 2: Calcium hydroxide paste, and Group 3: Casein phosphopeptide-amorphous calcium phosphate paste. The intracanal medicaments were placed on the canals for 7 days. The outcome of this procedure was measured by counting colony-forming units. Statistical analysis was carried out using One-Way ANOVA and Tukey’s Post Hoc Test to determine significant differences between the groups. Results: The mean bacterial count for Group 2 was significantly lower than Group 1 and Group 3. Calcium hydroxide showed significantly more antibacterial efficacy against Enterococcus faecalis than Casein phosphopeptide-amorphous calcium phosphate and the negative control groups. Conclusion: Casein Phosphopeptide-amorphous calcium phosphate is ineffective in inhibiting Enterococcus faecalis growth compared to Calcium hydroxide.

Bonding a titanium plate and soft tissue interface by using an adhesive bone paste composed of α-tricalcium phosphate and α-cyclodextrin/nonanyl group-modified poly(vinyl alcohol) inclusion complex

Adhesive bone pastes for dental implants and soft tissue interfaces were developed using α-tricalcium phosphate (α-TCP) and α-cyclodextrin (α-CD)/nonanyl group-modified poly(vinyl alcohol) (C9-PVA) inclusion complex solution (ICS). The thixotropic solution of α-CD/C9-PVA ICS was prepared by mixing α-CD and C9-PVA in deionized water. The α-CD/C9-PVA bone paste led to the highest bonding and shear adhesion between commercial pure titanium plates and soft tissue like collagen casing. Moreover, the compressive strength of these pastes reached 14.1 ± 3.8 MPa within 24 h incubation. Young's modulus of the α-CD/C9-PVA bone paste was lower than that of commercial calcium phosphate paste. Furthermore, the surface of α-CD/C9-PVA bone paste demonstrated excellent cell adhesion for cultured L929 fibroblast cells. Overall, the α-CD/C9-PVA bone paste can likely be effectively used to adhere dental implant abutments and soft tissue interfaces.

Association of Nd:YAG laser and calcium-phosphate desensitizing pastes on dentin permeability and tubule occlusion.

Objective To evaluate the efficacy of Nd:YAG laser associated with calcium-phosphate desensitizing pastes on dentin permeability and tubule occlusion after erosive/abrasive challenges.Methodology Dentin specimens were exposed to 17% ethylene diamine tetra-acetic acid (EDTA) solution for 5 min and randomly allocated into five groups: G1, control (no treatment); G2, Nd:YAG laser (1 W, 10 Hz, 100 mJ, 85 J/cm2); G3, Laser + TeethmateTM Desensitizer; G4, Laser + Desensibilize Nano P; and G5, Laser+Nupro®. Specimens underwent a 5-day erosion-abrasion cycling. Hydraulic conductance was measured post-EDTA, post-treatment, and post-cycling. Post-treatment and post-cycling permeability (%Lp) was calculated based on post-EDTA measurements, considered 100%. Open dentin tubules (ODT) were calculated at the abovementioned experimental moments using scanning electron microscopy and ImageJ software (n=10). Data were analyzed using two-way repeated measures ANOVA and Tukey’s test (α=0.05).Results G1 presented the highest %Lp post-treatment of all groups (p<0.05), without significantly differences among them. At post-cycling, %Lp significantly decreased in G1, showed no significant differences from post-treatment in G3 and G4, and increased in G2 and G5, without significant differences from G1 (p>0.05). We found no significant differences in ODT among groups (p>0.05) post-EDTA. At post-treatment, treated groups did not differ from each other, but presented lower ODT than G1 (p<0.001). As for post-cycling, we verified no differences among groups (p>0.05), although ODT was significantly lower for all groups when compared to post-EDTA values (p<0.001).Conclusion All treatments effectively reduced dentin permeability and promoted tubule occlusion after application.Combining Nd YAG laser with calcium-phosphate pastes did not improve the laser effect. After erosive-abrasive challenges, treatments presented no differences when compared to the control.

The Efficacy of Non-fluoridated Toothpastes on Artificial Enamel Caries in Primary Teeth: An In Vitro Study.

ABSTRACTAims:The aim of this study was to evaluate the remineralizing effect among various non-fluoridated toothpastes on artificial caries in primary teeth.Materials and Methods:Fifty sound primary incisor teeth were embedded in self-curing acrylic resin and immersed in demineralizing solution for 4 days forming artificial caries. All teeth were divided into five groups (10 teeth/group): Group I deionized water (control); Group II 1000 ppm F (Kodomo®); Group III non-fluoridated toothpaste containing calcium glycerophosphate and calcium lactate (Dokbuaku®); Group IV casein phosphopeptides-amorphous calcium phosphate (CPP-ACP) paste (GC Tooth Mousse®), and Group V non-fluoridated toothpaste containing nanohydroxyapatite (NHA) (Apagard®). The specimens were subjected to pH-cycling and immersed in toothpaste slurry twice for 7 days. Baseline, before, and after pH-cycling surface microhardness (SMH) values were measured by Vickers hardness numbers, and the percentage recovery of SMH (%SMHR) was calculated. Data were analyzed by one-way analysis of variance and Tukey’s multiple comparison at 95% confidence intervals.Results:The SMH values of test groups were significantly higher than those of the control group (p = 0.00). The %SMHR was −5.72±7.03% in the control group, Group II was significantly higher than Group III but there were no significant differences among Groups II, IV, and V (p > 0.05).Conclusion:Non-fluoridated toothpastes containing CPP-ACP or NHA for young children had efficacy in remineralizing effect on primary teeth comparable with 1000 ppm fluoridated toothpaste.

Remineralization Potential and Shear Bond Strength of Surface Treated Hypomineralized Enamel in Bonding of Orthodontic Brackets: An In Vitro Study

Aim: To investigate the effect of different conditioning methods on remineralization potential of hypomineralized enamel and its shear bond strength (SBS) to orthodontic brackets. Materials and Methods: An in vitro study was conducted at Mansoura University, Egypt. Eighty premolars were collected and randomly classified into four groups ( n = 20 each) as follows: Group 1. Control (sound teeth), Group 2. Demineralized, Group 3. Demineralized and treated with nanohydroxyapatite (nano-HA) varnish, Group 4. Demineralized and treated with casein phosphopeptide–amorphous calcium phosphate (CPP–ACP) paste. To detect the rate of remineralization on the surface of treated specimens, energy dispersive X-ray (EDX) analysis was used in conjunction with the scanning electron microscope (SEM). The SBS was measured with a universal testing machine. One-way ANOVA test was carried out to analyze differences between the tested groups. Result: SE micrographs of Group 3 and Group 4 specimens showed smoother and less porous enamel surface than that of the Group 2 specimens. EDX analysis showed highest calcium (Ca) (25.47%) and phosphorous (P) (12.76%) values for Group 4 while Group 2 showed the lowest Ca and P values (16.96%) and (10.20%), respectively ( P &lt; .001). Demineralized enamel showed lowest (3.70 MPa) SBS mean value compared to sound (10.69 MPa) and remineralized enamel (Group 3—9.90 MPa, Group 4—10.32 MPa) ( P &lt; .001). Conclusion: Nano-HA and CPP–ACP have equal remineralizing effect on hypomineralized enamel lesions and positive influence on SBS.

The effect of proanthocyanidin and casein phosphopeptide-amorphous calcium phosphate on the bond strength durability to caries-affected dentin.

ObjectivesThe aim of this study was to evaluate the effect of proanthocyanidin (PA) and casein phosphopeptide‐amorphous calcium phosphate (CPP‐ACP) paste on the micro‐shear bond strength (μSBS) durability of an etch‐and‐rinse adhesive to caries‐affected dentin (CAD).Materials and methodsThe occlusal surfaces of 80 human molars with occlusal caries were ground to expose flat dentin surfaces with CAD. Then, they were randomly divided into four groups (n = 20) according to the CAD pretreatment. The study groups included no pretreatment, pretreatment with CPP‐ACP for 3 min, pretreatment with PA for 1 min, and pretreatment with PA for 1 min followed by CPP‐ACP for 3 min before adhesive application. After restoring the specimens with composite resin, μSBS testing was performed for half of the bonded surfaces in each group after 24 h and the other half was tested after 6 months of water storage and failure mode analysis was performed.ResultsThe PA group was associated with a higher μSBS than the control and CPP‐ACP groups after 24 hours (p < 0.05). No significant difference was observed regarding the μSBS of the control and the other groups after 24 h (p > 0.05). No significant difference was observed regarding the μSBS of the PA and PA + CPP‐ACP groups (p > 0.05). The μSBS of the 6‐month specimens was significantly lower than those of the 24‐h specimens for all the groups (p < 0.05) except for the PA group which did not exhibit a significant difference between the two times (p > 0.05). The most common type of failure was mixed failure.ConclusionPA pretreatment could stabilize the CAD‐resin interface and protect degradation over time. The same effect was not observed for CPP‐ACP or PA + CPP‐ACP.

Ceramic 3D-Printed Titanium Cranioplasty.

Inlay cranioplasties following partial craniectomy in tumor or trauma cases and onlay cranioplasties for reconstructions of residual developmental skull anomalies are frequently performed using CAD-CAM techniques. In this case series, we present a novel cranial implant design, being a combination of 3D-printed titanium grade 23 and calcium phosphate paste (CeTi). The titanium patient-specific implant, manufactured using selective laser melting, has a latticed border with interconnected micropores. The cranioplasty is miniscrew fixed and its border zone subsequently partially filled with calcium phosphate paste to promote osteoinduction and osteoconduction. From April 2017 to April 2019, 8 patients have been treated with such a CeTi implant. The inlay cranioplasties were each time revision surgeries of complicated cases. All implants were successful after a limited follow-up time (range 18-42 months). There were no dehiscences and no infections, and no complaints of thermal conduction. The proposed CeTi cranial implant combines the strength of titanium implants with the biological integration potential of ceramic implants and seems particularly resistant to infection, probably due to the biofunctionalized titanium surface and the antimicrobial activity of elevated intracellular free calcium levels.

Reduction of inflammation in a chronic periodontitis model in rats by TNF-α gene silencing with a topically applied siRNA-loaded calcium phosphate paste

We developed a calcium phosphate-based paste containing siRNA against TNF-α and investigated its anti-inflammatory and bone-healing effects in vitro and in vivo in a rat periodontitis model. The bioactive spherical CaP/PEI/siRNA/SiO2 nanoparticles had a core diameter of 40–90 nm and a positive charge (+23 mV) that facilitated cellular uptake. The TNF- α gene silencing efficiency of the nanoparticles in J774.2 monocytes, gingival-derived cells, and bone marrow-derived cells was 12 ± 2%, 36 ± 8%, and 35 ± 22%, respectively. CaP/PEI/siRNA/SiO2 nanoparticles cancelled the suppression of alkaline phosphatase (ALP) activity in LPS-stimulated bone marrow-derived cells. In vivo, ALP mRNA was up-regulated, TNF-α mRNA was down-regulated, and the amount of released TNF-α was significantly reduced after topical application of the calcium phosphate-based paste containing siRNA-loaded nanoparticles. The number of TNF-α-positive cells in response to CaP/PEI/siRNA/SiO2 nanoparticle application was lower than that observed in the absence of siRNA. Elevated ALP activity and numerous TRAP-positive cells (osteoclasts) were observed in response to the application of all calcium phosphate pastes. These results demonstrate that local application of a paste consisting of siRNA-loaded calcium phosphate nanoparticles successfully induces TNF-α silencing in vitro and in vivo and removes the suppression of ALP activity stimulated by inflammation. Statement of significanceWe developed a calcium phosphate-based paste containing nanoparticles loaded with siRNA against TNF-α. The nanoparticles had a core diameter of 40–90 nm and positive charge (+23 mV). The anti-inflammatory and osteoinductive effects of the paste were investigated in vitro and in vivo in a rat periodontitis model. In vitro, the TNF-α gene silencing efficiency of the nanoparticles in J774.2 monocytes, gingival-derived cells, and bone marrow-derived cells was 12 ± 2%, 36 ± 8%, and 35 ± 22%, respectively. The ALP activity of bone marrow-derived cells was recovered. In vivo, TNF-α mRNA was down-regulated and the amount of released TNF-α was significantly reduced, whereas the ALP mRNA was up-regulated. Elevated ALP activity and TRAP-positive cells were observed by immunohistochemistry.

Resistance of bonded premolars to four artificial ageing models post enamel conditioning with a novel calcium-phosphate paste.

BackgroundThis in vitro study compares a novel calcium-phosphate etchant paste to conventional 37% phosphoric acid gel for bonding metal and ceramic brackets by evaluating the shear bond strength, remnant adhesive and enamel damage following water storage, acid challenge and fatigue loading. Material and MethodsMetal and ceramic brackets were bonded to 240 extracted human premolars using two enamel conditioning protocols: conventional 37% phosphoric acid (PA) gel (control), and an acidic calcium-phosphate (CaP) paste. The CaP paste was prepared from β-tricalcium phosphate and monocalcium phosphate monohydrate powders mixed with 37% phosphoric acid solution, and the resulting phase was confirmed using FTIR. The bonded premolars were exposed to four artificial ageing models to examine the shear bond strength (SBS), adhesive remnant index (ARI score), with stereomicroscopic evaluation of enamel damage. ResultsMetal and ceramic control subgroups yielded significantly higher (p < 0.05) SBS (17.1-31.8 MPa) than the CaP subgroups (11.4-23.8 MPa) post all artificial ageing protocols, coupled with higher ARI scores and evidence of enamel damage. In contrast, the CaP subgroups survived all artificial ageing tests by maintaining adequate SBS for clinical performance, with the advantages of leaving unblemished enamel surface and bracket failures at the enamel-adhesive interface. ConclusionsEnamel conditioning with acidic CaP pastes attained adequate bond strengths with no or minimal adhesive residue and enamel damage, suggesting a suitable alternative to the conventional PA gel for orthodontic bonding. Key words:Enamel etching, calcium phosphate, bracket bond strength, adhesive residue, enamel damage.