The effect of recommending a CPP-ACPF product on salivary and plaque pH levels in orthodontic patients: a randomized cross-over clinical trial.

OBJECTIVE: Along with their re-mineralizing capacity, calcium phosphopeptide-amorphous calcium phosphate products combined with fluoride (CPP-ACPF) could also be beneficial by neutralizing acidic salivary and plaque pH. The purpose was to evaluate the effect of CPP-ACPF on salivary and plaque pH in orthodontic patients. MATERIALS AND METHODS: As a triple-blind, cross-over randomized trial, 30 orthodontic patients with fixed appliances (age range = 15.70 ± 4.08 years) were recruited and randomly assigned to two groups. A CPP-ACPF paste (MI Paste Plus, GC America, Alsip, IL) was used by group 1 (n = 15) and a placebo by group 2 (n = 15) for 1 month. After a 1 month washout period, patients used the alternative paste for another month. Plaque and salivary pH levels were measured at all before and after periods. RESULTS: By applying MI Paste Plus, the plaque pH increased from 5.81 ± 0.45 to 6.60 ± 0.38 (p < 0.05), whereas the before and after salivary pH recordings, which were 6.72 ± 0.43 and 6.71 ± 0.38, respectively, remained statistically unchanged (p > 0.05). CONCLUSION: MI Paste Plus can be clinically beneficial in increasing plaque pH levels, but has no effect on the salivary pH.

Effect of pH on compressive strength of some modification of mineral trioxide aggregate.

OBJECTIVES: Recently, it was shown that NanoMTA improved the setting time and promoted a better hydration process which prevents washout and the dislodgment of this novel biomaterial in comparison with WTMA. This study analyzed the compressive strength of ProRoot WMTA (Dentsply), a NanoWMTA (Kamal Asgar Research Center), and Bioaggregate (Innovative Bioceramix) after its exposure to a range of environmental pH conditions during hydration. STUDY DESIGN: After mixing the cements under aseptic condition and based on the manufacturers` recommendations, the cements were condensed with moderate force using plugger into 9 × 6 mm split molds. Each type of cement was then randomly divided into three groups (n=10). Specimens were exposed to environments with pH values of 4.4, 7.4, or 10.4 for 3 days. Cement pellets were compressed by using an Instron testing machine. Values were recorded and compared. Data were analyzed by using one-way analysis of variance and a post hoc Tukey's test. RESULTS: After 3 days, the samples were solid when probed with an explorer before removing them from the molds. The greatest mean compressive strength 133.19 ± 11.14 MPa was observed after exposure to a pH value of 10.4 for NanoWMTA. The values decreased to 111.41 ± 8.26 MPa after exposure to a pH value of 4.4. Increasing of pH had a significant effect on the compressive strength of the groups (p<0.001). The mean compressive strength for the NanoWMTA was statistically higher than for ProRoot WMTA and Bioaggregate (p<0.001). Moreover, increasing of pH values had a significant effect on compressive strength of the experimental groups (p<0.001). CONCLUSION: The compressive strength of NanoWMTA was significantly higher than WMTA and Bioaggregate; the more acidic the environmental pH, the lower was the compressive strength.

Dental public health post-graduate trainees in the US: Experiences, challenges, and opportunities-A qualitative study.

OBJECTIVES: The goal of this study was to explore challenges and opportunities that dental public health (DPH) residents and recent graduates experienced during and after their residency training programs in the US. METHODS: In this qualitative study, to recruit participants, study invitations were distributed to 93 DPH postgraduate trainees via social media, email, and an online DPH nationwide course in 2019. Semi-structured in-depth interviews were conducted through Zoom audioconference. The interviews were conducted until thematic saturation was achieved. The audio-recorded interviews were transcribed and crosschecked to ensure accuracy. The interviews were coded using grounded theory. A qualitative analysis software (ATLAS.ti 8.0) was used to facilitate coding and organizing data extraction from transcripts. RESULTS: Eighteen DPH postgraduate trainees from 12 DPH residency programs participated and completed the interview. DPH trainees had experienced educational and financial challenges, difficulty finding DPH-related jobs after graduation, and a complex board examination preparation process. CONCLUSION: DPH postgraduate trainees and especially foreign-trained dentists experienced serious challenges during and after their postgraduate residency programs. Opportunities exist to enhance the strength of DPH programs to build a competent DPH workforce.

Coronavirus Disease Update on Epidemiology, Virology, and Prevention.

In March 2020, the World Health Organization declared COVID-19 as the first coronavirus-initiated pandemic. COVID-19's fast-paced global spread with a broad range of clinical manifestations compelled health regulatory organizations, public health professionals, and researchers to update their information about the disease and provide individual- and community-based guidelines, solutions, and regulations to break the disease cycle, mitigate person-to-person transmission, and reduce cross-contamination in healthcare settings. In this review, the authors provide known facts and updated information about SARS-CoV-2 virology and its new variants, transmission routes, reported clinical symptoms, epidemiology, and infection control and prevention guidelines with a focus on a hierarchy of controls in dental settings.

Effect of protective coating on microhardness of a new glass ionomer cement: Nanofilled coating versus unfilled resin.

BACKGROUND AND OBJECTIVES: EQUIATM is a new gastrointestinal (GI) system with high compressive strength, surface microhardness (MH), and fluoride release potential. This in vitro study aimed to assess the effect of aging and type of protective coating on the MH of EQUIATM GI cement. MATERIALS AND METHODS: A total of 30 disc-shaped specimens measuring 9 mm in diameter and 2 mm in thickness were fabricated of EQUIATM GI and divided into three groups of G-Coat nanofilled coating (a), no coating (b) and margin bond (c). The Vickers MH value of specimens was measured before (baseline) and at 3 and 6 months after water storage. Data were analyzed using repeated measures ANOVA. RESULTS: Group B had significantly higher MH than the other two groups at baseline. Both G-Coat and margin bond increased the surface MH of GI at 3 and 6 months. The MH values of G-Coat and margin bond groups did not significantly increase or decrease between 3 and 6 months. CONCLUSION: The increase in MH was greater in the G-Coat compared to the margin bond group in the long-term. Clinically, margin bond may be a suitable alternative when G-Coat is not available.

The effect of casein phosphopeptide amorphous calcium phosphate fluoride paste (CPP-ACPF) on oral and salivary conditions of patients undergoing chemotherapy: A randomized controlled clinical trial.

BACKGROUND: Oral and saliva conditions of patients undergoing chemotherapy is often affected by the medication they receive. Up to now, no appropriate medication that possesses the positive effects of chemotherapy without presenting oral complications has been introduced. OBJECTIVE: The aim of this study was to assess the clinical effects of CPP-ACPF paste on the oral and salivary status of patients undergoing chemotherapy. METHODS: From October 2013 to April 2014, 20 patients in chemotherapy treatment plans and who met the inclusion criteria enrolled in this randomized parallel single-blind controlled clinical trial in Shohada-e-Tajrish Hospital in Tehran, Iran. Patients were divided into two groups: 1) patients received their daily medication of cancer therapy center (group 1, control); 2) patients applied CPP-ACPF Crème (MI paste plus, GC USA) twice a day as instructed (group 2). The baseline status of oral conditions of patients (mucositis, dry mouth, infection, diminished tasting sense, difficulty in food intake, burning sensation of mucosa, saliva and dental plaque pH, rest and stimulated saliva, buffering capacity of saliva) were recorded and reevaluated after 21 and 42 days. The data were analyzed with a Mann-Whitney U-test. RESULTS: A total of 20 patients were allocated randomly to groups 1 and 2. The Mann-Whitney U-test showed that application of CPP-ACPF paste twice daily did not cause any significant difference in oral complication of the subject group compared with the control group (p>0.05). Among salivary signs, resting and stimulated saliva rates and saliva buffering capacity had significantly altered in the CPP-ACPF group in day 21 and 42 in comparison with those of the control group (p<0.05). CONCLUSION: Application of CPP-ACPF paste before and during chemotherapy can improve the salivary status of patients undergoing this treatment.

Histological Evaluation of Single and Double-visit Direct Pulp Capping with Different Materials on Sound Human Premolars: A Randomized Controlled Clinical Trial.

INTRODUCTION: The aim of this study was to evaluate the clinical and histological status of the pulp in sound human premolars after direct pulp capping (DPC) with four different DPC methods/materials. METHODS AND MATERIALS: This study was conducted on eight volunteers who had to extract four first premolars due to orthodontic treatment. Subsequent to tooth isolation, standardized class I occlusal cavities were prepared and the buccal pulp horns were exposed. Then four different protocols of DPC were applied randomly: group A (control); calcium hydroxide lining paste (Dycal), group B; ProRoot MTA (standard double-visit method), group C; ProRoot MTA (single-visit method) and group D; calcium hydroxide injectable paste (Multi-Cal). The cavities were then restored and the patients were put on a six-week clinical follow-up and by the end of this period the teeth were extracted for histological evaluation. Data were analyzed with the Kruskal Wallis test and the level of significance was set at 0.05. RESULTS: In terms of clinical symptoms and formation of hard tissue bridge (HTB), no significant differences were found between groups A, B and C (P>0.05); however, group D's results were significantly different as they exhibited minimal HTB formation and excessive sensitivity (P<0.05). Inflammation was significantly lower in group B (P>0.05). CONCLUSION: Application of MTA during a single-visit protocol of DPC was clinically and histologically as successful as the standard double-visit method but the routine use of Multi-Cal as pulp capping material is questionable and should be reconsidered.

Impact of Dilution and Polymerization on Cytotoxicity of Dentin Adhesives to Human Gingival Fibroblasts: Early Exposure Time.

Background and aims. The aim of this study was to evaluate the effect of dilution and curing methods of an etch-and-rinse adhesive and a self-etching primer from the same manufacturer at early exposure time on cytotoxicity of primary human gingival fibroblasts. Materials and methods. Primary human gingival fibroblasts were exposed to different dilutions of Adper Single Bond (ASB) and Adper Prompt L-Pop (APL) (3M ESPE, USA). They were evaluated in unpolymerized mode for 20 s, 5 min and 24 h and in polymerized mode for 24 h and 48 h. Cytotoxicity was evaluated using three cytotoxic tests (MTT, cell counting and DNA condensation). Data was analyzed by a one-way ANOVA and Post Hoc Tukey HSD test. Results. Cytotoxicity tests revealed that unpolymerized APL was more cytotoxic compared to ASB after 20 s (P<0.05). By increasing the time to 5 min and 24 h, ASB was more cytotoxic than APL with lower dilutions. Polymerized ASB was more toxic than APL. Conclusion. Both adhesives were cytotoxic in different dilutions, times and curing modes. Cytotoxicity of the unpolymerized self-etching primer (APL) was more than etch-and-rinse adhesive (ASB) in 20 s, which is important clinically and dentists should be aware of the harmful effects and try to minimize it by curing and rinsing soon after composite resin insertion. ASB was more cytotoxic at 5 min and 24h.

Correlation between long-term in vivo amalgam restorations and the presence of heavy elements in the dental pulp.

PROJECT: To measure the levels of heavy metals (Hg, Sn) in the dental pulp and blood samples of patients with long-term amalgam restorations. PROCEDURE: 12 amalgam restored and 12 non-restored, sound teeth were chosen and access cavity preparation to the pulp chamber was made. The contents were transferred and dissolved in 5mL of concentrated nitric acid followed by placement in an oven at 180°C for tissue digestion. After cooling the tubes each digested sample was transferred to an atomic absorption system to measure the levels of heavy metals. The blood samples of five patients in each group were randomly analyzed to determine the levels of these heavy metals in the blood and if there were a correlation between these levels in blood and pulp. Data were analyzed by t-test at a P<0.05 level of significance. RESULTS: No significant difference was seen between the levels of Hg and Sn in pulp tissues (P>0.05); however, the blood analysis showed higher level of Hg amalgam group (P=0.009). The analysis between the pulp and blood samples showed positive correlations for both Hg and Sn elements in dental pulp and the blood (P=1.000) (P=0.900). CONCLUSIONS: The long-term presence of dental amalgam (at least 5 years) did not result in any remarkable changes in the levels of mercury and tin in the pulp tissue; however, there were increases in the level of mercury in the blood circulation even five years following the placement of the restoration.

The effects of two attachment types on the stresses introduced to the mandibular residual ridge: a 3D finite element analysis.

PURPOSE: Two commonly used attachment systems for implant-retained overdentures are bar and ball systems. The aim of this study was to compare these two types of attachments on the basis of the stresses introduced to the mandibular posterior residual ridge by an overdenture retained by two implants. METHOD AND MATERIALS: A basic model was generated from the data provided by a CT scan of a patient's mandible, the diagnostic casts, and the existing overdenture. Two root-form implants were placed in the anterior mandible. Models were used to simulate two situations: The first model represented an edentulous mandible supporting an overdenture retained by two implants connected with a bar and plastic clip system, and in the second model two ball attachments with nylon caps were used as the retention mechanism. A 35 N vertical load was introduced to the first molar region of each group to simulate the occlusal forces of the maxillary complete denture. The stresses in the mandibular residual ridges under the first molar region were measured using Ansys software. RESULTS: The bar-retained overdenture introduced higher stresses to the posterior mandibular residual ridge compared to the ball-retained overdenture (0.4 MPa and 0.1 MPa, respectively). CONCLUSION: Within the limitations of this study, the ball system was shown to introduce a lower amount of stress to the posterior mandibular residual ridge compared to a bar and clip system.