Trends and age-period-cohort effect on dental caries prevalence from 2008 to 2019 among Brazilian preschoolers.

This study aimed to evaluate trends in the prevalence of dental caries in preschool children and associated factors considering different time variations. This is a time series study performed using data from three cross-sectional studies with pre-school children from southern Brazil in 2008, 2013 and 2019. This children group was born between the years of 2003 to 2018. Dental caries was evaluated by decayed, missing and filled deciduous teeth (dmft index). Demographic, socioeconomic, behavioural and psychosocial variables were also collected. Chi-square test for trends and a hierarchical age-period-cohort (HAPC) analysis using multilevel Poisson regression model for testing the associations between predictor variables and dental caries experience were used. A total of 1,644 pre-school children participated in all surveys. There was a significant difference in caries experience considering all APC effects. The prevalence of dental caries was 25.0% in 2008, 16.3% in 2013, and 19.4% in 2019 (p < 0.01) and no statistical difference was observed. An age effect showed that older children were more likely to experience dental caries. Considering the cohort effect, there is a significant difference between the generations, mainly between 2003 and 2018. Household income, use of dental services, and parent's perception of child oral health were associated with dental caries experience no matter the time variation. Despite recent declines in dental caries prevalence among preschool children, caries levels increased with age and social inequalities persisted through the years, indicating a need of reviewing the policies to reduce the burden of this oral disease.

Trends and age-period-cohort effect on dental caries prevalence from 2008 to 2019 among Brazilian preschoolers

Abstract This study aimed to evaluate trends in the prevalence of dental caries in preschool children and associated factors considering different time variations. This is a time series study performed using data from three cross-sectional studies with pre-school children from southern Brazil in 2008, 2013 and 2019. This children group was born between the years of 2003 to 2018. Dental caries was evaluated by decayed, missing and filled deciduous teeth (dmft index). Demographic, socioeconomic, behavioural and psychosocial variables were also collected. Chi-square test for trends and a hierarchical age-period-cohort (HAPC) analysis using multilevel Poisson regression model for testing the associations between predictor variables and dental caries experience were used. A total of 1,644 pre-school children participated in all surveys. There was a significant difference in caries experience considering all APC effects. The prevalence of dental caries was 25.0% in 2008, 16.3% in 2013, and 19.4% in 2019 (p < 0.01) and no statistical difference was observed. An age effect showed that older children were more likely to experience dental caries. Considering the cohort effect, there is a significant difference between the generations, mainly between 2003 and 2018. Household income, use of dental services, and parent's perception of child oral health were associated with dental caries experience no matter the time variation. Despite recent declines in dental caries prevalence among preschool children, caries levels increased with age and social inequalities persisted through the years, indicating a need of reviewing the policies to reduce the burden of this oral disease.

Does bullying due to oral conditions influence cigarette smoking in adolescents? A structural equation modeling.

This study aimed to explore the pathways that can influence cigarette smoking among adolescents. This population-based cohort followed a random sample of 12-year-old adolescents from southern Brazil for 6 years. Regular cigarette smoking was assessed through a self-reported question, previously used in the Brazilian National Survey of Scholar Health. We also gathered data on bullying, dental caries at baseline, incidence of caries, sex, friend network, and Sense of Coherence (SOC). Socioeconomic and demographic characteristics were also collected. Structural equation modeling was used to evaluate the pathways. Of the 1,134 adolescents examined at baseline, 768 were re-evaluated (67.7% retention rate). The prevalence of smoking was 37.6%. This prevalence was directly affected by low SOC (SC: -0.14, p < 0.01), low household income (SC: -0.12, p < 0.01), and male sex (SC: 0.15, p < 0.01). Presence of dental caries at baseline indirectly influenced the occurrence of dental bullying at follow-up via the incidence of dental caries (SC: 0.01, p < 0.05). Dental bullying indirectly influenced cigarettes consumption via SOC (SC: 0.62, p < 0.05). Friend network also indirectly influenced the consumption of cigarettes via SOC (SC: 0.32, p < 0.05). Psychosocial factors influence adolescent cigarette consumption through its higher direct and indirect effects (via bullying). In addition, behavioral, sociodemographic, and clinical factors also influence the occurrence of smoking.

Metaresearch study highlights the gender gap in randomized controlled trials in dentistry.

BACKGROUND AND OBJECTIVES: This study aimed to assess the gender gap in randomized controlled trials (RCTs) in dentistry in terms of authorship, collaborations, metrics, funding and reporting of good research practice and transparecy. METHODS: The search was performed in PubMed for RCTs restricted to English texts in the dental field, indexed from 12/31/2016 to 12/31/2021. Two reviewers screened the studies in line with the eligibility criteria. A total of 844 articles were included. The name and gender of authors, citation metrics, funding, reporting of characteristics of good research practice and transparency were extracted. We considered "collaboration between authors" when the corresponding author was different from the first author. RESULTS: The proportion of women as first authors was 46.56% and 40.12% for corresponding authors. The analysis showed that when a woman is the corresponding author, the probability of the first author also being a woman is 57% higher compared to the first author being a man. For "protocol registration" and "data sharing," the prevalence of reporting was higher when women were first authors. CONCLUSION: A gender gap in dentistry RCTs was identified and related to the participation of women as first and corresponding authors and the collaboration between authors.

Exploring the use of preprints in dentistry.

OBJECTIVE: This study aims to assess the use, impact, and dissemination of preprints in dentistry. METHODS: This is a meta-research study with a cross-sectional design. We included preprints published in dentistry, regardless of the year of publication. Searches were performed in the medRxiv.org and Preprints.org platforms and restricted to English. One researcher extracted the data, and another researcher verified data consistency. The following data were extracted: year of publication, country of the corresponding author, number of abstract and full-text views and downloads, Altmetric attention score, whether the preprint was mentioned in other servers such as Twitter and Publons, number of mentions in other servers, number of citations in the Dimensions database, and whether the preprint had already been published in a peer-reviewed journal. If already published, we extracted the journal's impact factor (JCR 2021) and the number of citations in the Dimensions database. We conducted a descriptive analysis of the extracted characteristics and explored relationships between metrics using the Spearman correlation. RESULTS: We identified 276 preprints. Most of the studies were published between 2020 and 2022 (n = 229), especially those from ten countries. The most-cited preprint and published article are the same study. Only the correlation between the number of preprint citations and peer-reviewed article citations in the Dimensions database showed a large positive association (Spearman's rho = 0.5809). CONCLUSION: Preprints gained popularity over the last several years due to the COVID-19 pandemic and reached a larger audience, especially on platforms such as Twitter. CLINICAL SIGNIFICANCE: Preprint publishing allows faster dissemination of science for the benefit of society.

Direct relations between sense of coherence and oral health-related quality of life in adolescents.

OBJECTIVE: To verify the relations between sense of coherence (SOC) and dental caries on oral health-related quality of life (OHRQoL) of adolescents. SUBJECT AND METHODS: A cross-sectional sample of 768 adolescents nested in a cohort study was evaluated. SOC was measured using Antonovsky's scale. Dental caries was collected considering the decayed, missing, and filled teeth index (DMFT). OHRQoL was collected through the Child Perception Questionnaire. Demographic, socioeconomic, and use of service variables were also collected. The mediation effects between variables were tested by structural equation modeling. RESULTS: The average age of the individuals was 17.5 years. Individuals with high SOC scores had a positive impact on OHRQoL (ß-coefficient = -0.573, p < 0.00). Individuals with high DMFT (ß-coefficient = 0.080, p = 0.034) and dental pain (ß-coefficient = 0.079, p = 0.039) negatively impacted OHRQoL. Still, adolescents who had dental pain (ß-coefficient = 0.112, p = 0.005), mothers with lower education levels (ß-coefficient = -0.114, p = 0.004), lower household income (ß-coefficient = -0.131, p = 0.003), and those who visited the dentist (ß-coefficient = 0.109, p = 0.005) exhibited a higher DMFT index. CONCLUSIONS: SOC and dental caries had a direct effect on OHRQoL, indicating that oral conditions and psychosocial characteristics are important contributors to OHRQoL.

Does bullying due to oral conditions influence cigarette smoking in adolescents? A structural equation modeling

Abstract This study aimed to explore the pathways that can influence cigarette smoking among adolescents. This population-based cohort followed a random sample of 12-year-old adolescents from southern Brazil for 6 years. Regular cigarette smoking was assessed through a self-reported question, previously used in the Brazilian National Survey of Scholar Health. We also gathered data on bullying, dental caries at baseline, incidence of caries, sex, friend network, and Sense of Coherence (SOC). Socioeconomic and demographic characteristics were also collected. Structural equation modeling was used to evaluate the pathways. Of the 1,134 adolescents examined at baseline, 768 were re-evaluated (67.7% retention rate). The prevalence of smoking was 37.6%. This prevalence was directly affected by low SOC (SC: -0.14, p < 0.01), low household income (SC: -0.12, p < 0.01), and male sex (SC: 0.15, p < 0.01). Presence of dental caries at baseline indirectly influenced the occurrence of dental bullying at follow-up via the incidence of dental caries (SC: 0.01, p < 0.05). Dental bullying indirectly influenced cigarettes consumption via SOC (SC: 0.62, p < 0.05). Friend network also indirectly influenced the consumption of cigarettes via SOC (SC: 0.32, p < 0.05). Psychosocial factors influence adolescent cigarette consumption through its higher direct and indirect effects (via bullying). In addition, behavioral, sociodemographic, and clinical factors also influence the occurrence of smoking.

Prevalence of psychological disorders in patients with temporomandibular disorders: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Temporomandibular disorders (TMDs) affect the muscles of mastication, the temporomandibular joint, and associated structures. They are generally classified as muscular or articular and are the main cause of pain in the orofacial region, eventually causing psychological problems. However, the real burden of psychological disorders is unknown. PURPOSE: The purpose of this systematic review and meta-analysis was to assess the prevalence of psychological disorders in patients with TMDs. MATERIAL AND METHODS: The study was conducted through a bibliographic search carried out without initial limit until July 2021 in the following electronic databases: MEDLINE/PubMed, Scopus, and PsycINFO. Clinical observational studies investigating depression and somatization in patients with TMD diagnosed by the Diagnostic Research for Temporomandibular Disorders (RDC/TMD) criteria in muscular, articular, and disc disorders were included. A descriptive analysis of the included studies and a meta-analysis for the prevalence data were performed for the synthesis of evidence. RESULTS: A total of 2320 studies were found, of which 48 complete articles were assessed for eligibility and 22 were included in the analysis. The general prevalence of depression and moderate and severe somatization in patients diagnosed with TMD was estimated at 43.0% (95% confidence interval (CI), 36.0% to 50.0%) and 60.0% (95% CI 52.0 - 67, 0%). The average overall score for depression was estimated at 0.92 (95% CI, 0.69-1.15), being classified as moderate depression. The average overall score for somatization was estimated at 1.09 (95% CI, 0.81-1.36), being classified as severe somatization. All analyses showed high heterogeneity (I2>90%). Based on the quality assessment, 80.9% of studies included in the review had low to moderate risk of bias. CONCLUSIONS: Patients with TMDs who seek clinical care show a high prevalence of depression and somatization.

There is room for improvement in the use of scoping reviews in dentistry.

OBJECTIVE: To evaluate the reporting of authors' justifications for choosing the scoping review methodology in oral health. STUDY SELECTION, DATA AND SOURCE: This is a meta-research study about scoping reviews in dentistry. This study searched for reviews in PubMed and Scopus without year restrictions and restricted to English-language publications. Study selection was undertaken by two reviewers independently. Each of these reviewers extracted data from half of the included studies considering general study characteristics and scoping reviews objectives, as well as data about whether or not the authors clearly explained why they chose the scoping review framework. RESULTS: We included 184 articles. Ninety-seven of the reports did not provide a rationale as to why they chose the scoping review method (52.7%). Regarding the reported aims of the studies, 29.9% (n = 29/87) of the scoping reviews presented more than one. When comparing studies reporting the use of the PRISMA-ScR to those not reporting the PRISMA-ScR, there is no difference in the reporting of a clear explanation of why the authors used a scoping review method. CONCLUSION: There is room for improvement in how authors report their justifications for choosing the scoping review method. CLINICAL SIGNIFICANCE: Scoping reviews may be used by researchers who are unaware of this method. Educational initiatives should thus be encouraged.

Self-reported oral health and normative indices of dental caries among adolescents: a cohort study.

This study assessed the association between self-reported oral health and the normative indices of dental caries in an adolescent population. This study is based on a 6-year data from a cohort, beginning in 2012, with 1,134 twelve-year-old adolescents. After three phases of data collection, 68% of the samples were followed up. Self-reported oral health was evaluated through the question: "Would you say that the health of your teeth, lips, jaws, and mouth is …?", and answers were categorized as "good" or "poor." Calibrated dentists examined clinical conditions using the decayed, missing, and filled teeth (DMFT) index. Statistical analysis was performed using multilevel logistic regression models, considering the dependence of those observed thrice and adjusted for demographic, socioeconomic, and dental visit variables. Adolescents who evaluated their oral health as poor had higher mean DMFT (OR: 1.35; CI95% 1.22-1.50). When evaluated separately, decayed (OR: 2.43; CI95% 1.83-3.23) and missing (OR: 3.94; CI95% 1.26-12.26) teeth also presented significant results, showing poor self-reported oral health associated with a higher mean. Adolescents' self-perceived oral health was associated with normative dental caries indices, and this association was maintained throughout adolescence.

Self-reported oral health and normative indices of dental caries among adolescents: a cohort study

Abstract: This study assessed the association between self-reported oral health and the normative indices of dental caries in an adolescent population. This study is based on a 6-year data from a cohort, beginning in 2012, with 1,134 twelve-year-old adolescents. After three phases of data collection, 68% of the samples were followed up. Self-reported oral health was evaluated through the question: "Would you say that the health of your teeth, lips, jaws, and mouth is …?", and answers were categorized as "good" or "poor." Calibrated dentists examined clinical conditions using the decayed, missing, and filled teeth (DMFT) index. Statistical analysis was performed using multilevel logistic regression models, considering the dependence of those observed thrice and adjusted for demographic, socioeconomic, and dental visit variables. Adolescents who evaluated their oral health as poor had higher mean DMFT (OR: 1.35; CI95% 1.22-1.50). When evaluated separately, decayed (OR: 2.43; CI95% 1.83-3.23) and missing (OR: 3.94; CI95% 1.26-12.26) teeth also presented significant results, showing poor self-reported oral health associated with a higher mean. Adolescents' self-perceived oral health was associated with normative dental caries indices, and this association was maintained throughout adolescence.

Survival of atraumatic restorative treatment restorations in the elderly patients: a systematic review.

This study aimed to assess the survival of glass ionomer cement (GIC) restorations performed using the atraumatic restorative treatment (ART) in elderly patients. The systematic review protocol was registered in the PROSPERO database. The records were searched until August 2020 in eight electronic bibliographic databases, and included randomized and non-randomized clinical trials and observational studies, with no restrictions on the language or year of publication. Study selection and data extraction were performed independently by two reviewers. Data were extracted, summarized, collected for qualitative analysis, and evaluated for individual risk of bias using the Joanna Briggs Institute's Critical Appraisal Tool. The literature search retrieved 5,186 records; however, only seven studies fulfilled the eligibility criteria and were included. The studies were published between 2002 and 2019. A total of 1,239 restorations were investigated at intervals of 6, 12, 24, and 60 months of follow-up. Some studies had a low risk of bias, while others had moderate and high risk of bias. In general, GIC restorations placed using ART were considered satisfactory. The 6-month, 12-month, and 24-month survival rates ranged from 81.3% to 97.2%, 72.2% to 94%, and 63% to 87%, respectively; additionally, the survival rate for the longest follow-up period (60 months) was 85%. Given the best evidence-based information regarding caries removal, we highlight the need to provide a conservative and effective technique for use in elderly patients. ART is a promising and viable alternative that guarantees the survival of restorations in elderly patients.

How are meta-analyses being conducted and reported in dentistry? A meta-research study

Aim: This study aimed to evaluate how meta-analyses are conducted and reported in dentistry. Methods: We conducted a search to identify dentistry-related Systematic Reviews (SRs) indexed in PubMed in 2017 (from January 01 until December 31) and published in the English language. We included only SRs reporting at least one meta-analysis. The study selection followed the 4-phase flow set forth in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA), and it was independently conducted by two researchers. Data extraction was performed by one of three reviewers, and data related to conducting and reporting of the meta-analysis were collected. Descriptive data analysis was performed summarizing frequencies for categorical items or median and interquartile range for continuous data. Results: We included 214 SRs with meta-analyses. Most of the studies reported in the title that a meta-analysis was conducted. We identified three critical flaws in the included studies: Ninety (90) meta-analyses (43.1%) did not specify the primary outcome; most of the meta-analyses reported that a measure of statistical heterogeneity was used to justify the use of a fixed-effect or random-effects meta-analysis model (n=114, 58.5%); and a great part did not assess publication bias (n=106, 49.5%). Conclusion: We identified deficiencies in the reporting and conduct of meta-analysis in dentistry, suggesting that there is room for improvement. Educational approaches are necessary to improve the quality of such analyses and to avoid biased and imprecise results

Prevalence of xerostomia and its association with systemic diseases and medications in the elderly: a cross-sectional study

ABSTRACT BACKGROUND: Dry mouth syndrome or xerostomia is defined as decreased salivary flow or hypofunction of salivary glands. Its origins are multicausal and might be the result of a change in the salivary glands or a systemic imbalance. OBJECTIVE: To ascertain the prevalence of self-reported xerostomia and to identify associated factors. DESIGN AND SETTING: Cross-sectional study on the entire population of 293 elderly people over 60 years of age living in a Brazilian municipality. METHODS: Data were gathered from a questionnaire that asked about demographic data, chronic diseases and use of continuous medications, and which used the Xerostomia Inventory (XI) to evaluate dry mouth sensation. Our analysis consisted of multivariate regression and estimation of odds ratios (OR) and their respective 95% confidence intervals (CI) in binary logistic regression models. RESULTS: The prevalence of self-reported xerostomia was 19.1%. Elderly people with diabetes had higher odds of having self-reported xerostomia (OR: 3.59; 95% CI: 1.48-8.68; P < 0.001) as did those who had chronic diseases and used continuous medication (OR: 2.3; 95% CI: 1.19-4.67; P = 0.009). Elderly people who used continuous medication for the gastrointestinal tract were more likely to have xerostomia (OR: 2.14; 95% CI: 1.03-1.44; P = 0.030). CONCLUSIONS: Elderly people with diabetes and chronic diseases who were using continuous medication were more likely to have dry mouth. Use of continuous medications for the gastrointestinal tract led to a greater chance of having self-reported xerostomia.

Prevalence of xerostomia and its association with systemic diseases and medications in the elderly: a cross-sectional study.

BACKGROUND: Dry mouth syndrome or xerostomia is defined as decreased salivary flow or hypofunction of salivary glands. Its origins are multicausal and might be the result of a change in the salivary glands or a systemic imbalance. OBJECTIVE: To ascertain the prevalence of self-reported xerostomia and to identify associated factors. DESIGN AND SETTING: Cross-sectional study on the entire population of 293 elderly people over 60 years of age living in a Brazilian municipality. METHODS: Data were gathered from a questionnaire that asked about demographic data, chronic diseases and use of continuous medications, and which used the Xerostomia Inventory (XI) to evaluate dry mouth sensation. Our analysis consisted of multivariate regression and estimation of odds ratios (OR) and their respective 95% confidence intervals (CI) in binary logistic regression models. RESULTS: The prevalence of self-reported xerostomia was 19.1%. Elderly people with diabetes had higher odds of having self-reported xerostomia (OR: 3.59; 95% CI: 1.48-8.68; P < 0.001) as did those who had chronic diseases and used continuous medication (OR: 2.3; 95% CI: 1.19-4.67; P = 0.009). Elderly people who used continuous medication for the gastrointestinal tract were more likely to have xerostomia (OR: 2.14; 95% CI: 1.03-1.44; P = 0.030). CONCLUSIONS: Elderly people with diabetes and chronic diseases who were using continuous medication were more likely to have dry mouth. Use of continuous medications for the gastrointestinal tract led to a greater chance of having self-reported xerostomia.

Influence of low-level laser therapy on implant stability in implants placed in healed sites: a randomized controlled trial.

BACKGROUND: The present study aims to assess the influence of low-level laser therapy (LLLT) on stability in implants placed in healed sites. MATERIAL AND METHODS: The present study followed the SPIRIT statement and is reported according to CONSORT. Patients were randomly allocated to LLLT or control groups. LLLT consisted in the application of 808-nm GaAlA laser applied before the preparation of the implant bed and after suturing (80 seconds; 11J/cm2). Implant stability quotient (ISQ) and the distance between the implant platform to the alveolar bone crest (millimeters) were assessed at implant placement (T0) and the abutment selection phase (4-6 months, Ta). RESULTS: A total of 64 implants were placed in 33 patients. The insertion torque ranged from 10 to 70 N.cm (mean 43.23; SD ±16.82). The T0 ISQ ranged from 18 to 95.5 (mean 61.7; SD ±18.23) and the crestal bone radiographic distance was 2.03 mm (SD±1.27). At Ta, the ISQ ranged from 39 to 90 (mean 64.2; SD±9.84), and the mean crestal bone radiographic loss was 1.70mm (SD±1.65). However, no differences were observed when LLLT and control groups were compared with ISQ difference (Ta-T0; p=0.598) or radiographical peri-implant alterations (p=0.531). CONCLUSION: LLLT did not influence the implant stability in implants placed in healed sites compared to a control group. TRIAL REGISTRATION: ReBEC, RBR-35TNJ7 . Registered May 23, 2018.

Survival of atraumatic restorative treatment restorations in the elderly patients: a systematic review

Abstract: This study aimed to assess the survival of glass ionomer cement (GIC) restorations performed using the atraumatic restorative treatment (ART) in elderly patients. The systematic review protocol was registered in the PROSPERO database. The records were searched until August 2020 in eight electronic bibliographic databases, and included randomized and non-randomized clinical trials and observational studies, with no restrictions on the language or year of publication. Study selection and data extraction were performed independently by two reviewers. Data were extracted, summarized, collected for qualitative analysis, and evaluated for individual risk of bias using the Joanna Briggs Institute's Critical Appraisal Tool. The literature search retrieved 5,186 records; however, only seven studies fulfilled the eligibility criteria and were included. The studies were published between 2002 and 2019. A total of 1,239 restorations were investigated at intervals of 6, 12, 24, and 60 months of follow-up. Some studies had a low risk of bias, while others had moderate and high risk of bias. In general, GIC restorations placed using ART were considered satisfactory. The 6-month, 12-month, and 24-month survival rates ranged from 81.3% to 97.2%, 72.2% to 94%, and 63% to 87%, respectively; additionally, the survival rate for the longest follow-up period (60 months) was 85%. Given the best evidence-based information regarding caries removal, we highlight the need to provide a conservative and effective technique for use in elderly patients. ART is a promising and viable alternative that guarantees the survival of restorations in elderly patients.

Saliva as a tool for monitoring hemodialysis: a systematic review and meta-analysis

Abstract This study aimed to assess whether the reductions in serum urea and creatinine levels are different from the reductions in salivary urea and creatinine levels that occur after hemodialysis in chronic renal patients. The systematic review protocol was registered in the PROSPERO database. Eight databases were searched to identify pretest-posttest studies of chronic kidney disease patients undergoing hemodialysis, with no language or year restrictions. The JBI Critical Appraisal Tool was used to assess the risk of bias. Meta-analyses using random-effect models were conducted to compare salivary and serum correlations and to pooled mean and proportion differences from pre- to posthemodialysis urea and creatinine levels by subgroup analysis. The I2 test was used to assess heterogeneity, and a meta-regression was performed to statistically assess correlations and differences in the pooled effects pre- and postdialysis. The Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) was used to assess the certainty of evidence. The search resulted in 1404 records, and only six studies (n = 252 participants) fulfilled the eligibility criteria and were included. The studies were published between 2013 and 2018. All studies showed a significant reduction in both salivary and serum urea/creatinine levels. All eligible studies presented a low risk of bias. The meta-analysis shows a moderate to high correlation between salivary and blood levels of urea (r: 0.79; 95% CI: 0.56-1.00) and creatinine (r: 0.64; 95%CI: 0.16-1.00), with a very low level of certainty. The reductions in salivary urea and creatinine levels are similar to and correlated with the reductions in blood urea and creatine levels after hemodialysis among chronic kidney disease patients.

Saliva as a tool for monitoring hemodialysis: a systematic review and meta-analysis.

This study aimed to assess whether the reductions in serum urea and creatinine levels are different from the reductions in salivary urea and creatinine levels that occur after hemodialysis in chronic renal patients. The systematic review protocol was registered in the PROSPERO database. Eight databases were searched to identify pretest-posttest studies of chronic kidney disease patients undergoing hemodialysis, with no language or year restrictions. The JBI Critical Appraisal Tool was used to assess the risk of bias. Meta-analyses using random-effect models were conducted to compare salivary and serum correlations and to pooled mean and proportion differences from pre- to posthemodialysis urea and creatinine levels by subgroup analysis. The I2 test was used to assess heterogeneity, and a meta-regression was performed to statistically assess correlations and differences in the pooled effects pre- and postdialysis. The Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) was used to assess the certainty of evidence. The search resulted in 1404 records, and only six studies (n = 252 participants) fulfilled the eligibility criteria and were included. The studies were published between 2013 and 2018. All studies showed a significant reduction in both salivary and serum urea/creatinine levels. All eligible studies presented a low risk of bias. The meta-analysis shows a moderate to high correlation between salivary and blood levels of urea (r: 0.79; 95% CI: 0.56-1.00) and creatinine (r: 0.64; 95%CI: 0.16-1.00), with a very low level of certainty. The reductions in salivary urea and creatinine levels are similar to and correlated with the reductions in blood urea and creatine levels after hemodialysis among chronic kidney disease patients.