Category: Statistics

Yi Chuan. 2026 May;48(5):483-505. doi: 10.16288/j.yczz.25-172.

ABSTRACT

Examining a greater number of short tandem repeats (STRs) is essential for cases involving mutations, consanguinity, and complex kinship testing. However, previous population studies were mostly limited to fewer than 40 STRs. Therefore, this study investigated the genetic polymorphism, linkage disequilibrium, and mutation rates of 81 autosomal STR loci in the Han Chinese population of northern China. We confirmed the core repeat structure of STR loci, and focused on evaluating the forensic application value of the Category C and 21 additional STR loci not included in the standard “Forensic science-Data structures of selected loci from the DNA database” (GB/T 41009-2021). Blood samples from 400 unrelated healthy Northern Han Chinese individuals and parent-child blood samples from 157 families were detected using GSTAR ^TM25, GSTAR ^TM31FS, and GSTAR ^TM29HS kits. Genetic analysis was performed on genotyping data of 81 autosomal STR loci. The core sequence structures of newly added 15 STR loci were confirmed by sequencing the allelic ladder. After applying Bonferroni correction, all 81 autosomal STR loci conformed to Hardy-Weinberg equilibrium. The observed heterozygosity ranged from 0.4375 to 0.9075, discrimination power from 0.6332 to 0.9845 (lowest at LPL), polymorphism information content from 0.3938 to 0.9092, probability of exclusion for trios from 0.1384 to 0.8108, and for duos from 0.0955 to 0.7069. Significantly, linkage disequilibrium was observed between D5S2500 and D5S2800 loci. When excluding the D5S2800 locus, the cumulative discrimination power (CDP) of remaining 80 autosomal STR loci was 1-2.293×10^-89, cumulative probability of exclusion (CPE) of trios was 1-5.074×10^-31, and cumulative exclusion probability of duos was 1-1.400×10^-19. A total of 13 mutations were observed across 508 meiotic events in 157 families at 10 STR loci. The mutation rates for D5S818, D11S2368 and D18S51 were 0.004, while those of D6S1043, D7S1517, D11S4463, D13S325, D14S1434, D20S482 and D20S85 were 0.002. In conclusion, the 81 genetic loci, including Category C and newly added STRs, exhibit good or moderate polymorphism and are suitable for individual identification, paternity testing, and kinship identification. Given the linkage disequilibrium between the D5S2500 and D5S2800, if simultaneous on the capillary electrophoresis platform, it is recommended to use only the test results from the D5S2500 locus for statistical analysis. This data generated provide allele frequency and mutation rate for a large number of STRs, along with the clarified core sequences, thus offering an important data foundation for DNA evidence evaluation.

PMID:42145195 | DOI:10.16288/j.yczz.25-172

J Obstet Gynaecol. 2026 Dec;46(1):2665632. doi: 10.1080/01443615.2026.2665632. Epub 2026 May 18.

ABSTRACT

BACKGROUND: The objective of this study was to review type 2 diabetes (T2D) remission and glycaemic improvement in gynaecologic oncology patients with class 3 obesity undergoing preoperative weight loss.

METHODS: This was a case series of 92 gynaecologic oncology patients with BMI ≥40 kg/m² and T2D who underwent preoperative weight loss with a low-calorie liquid meal replacement. Patients were classified as high or low likelihood of remission based on diabetes duration, glycated haemoglobin (A1C) and insulin use. Data were summarised descriptively and Fisher’s exact test and paired t-test were used as inferential statistics using SAS 9.4.

RESULTS: Twenty-one patients with a mean age of 57.8 (SD = 11.7) years completed a weight loss protocol of median 14 (IQR = 10.5-16.5) weeks. Eighteen (86%) had endometrioid endometrial carcinoma or atypical endometrial hyperplasia. Initial mean BMI and A1C were 48.0 (SD = 6.7) kg/m² and 8.2% (SD = 2.3%). After the protocol, mean BMI and A1C were 43.1 (SD = 5.5) kg/m² and 7.1% (SD = 1.7%). On average, A1C decreased 1.1% (95% CI: 0.5-1.6, p < 0.05) after weight loss. 3/21 patients experienced diabetes remission. The rate of remission was 2/6 and 1/15 for patients coded as high and low likelihood of remission (p = 0.18).

CONCLUSIONS: Weight, BMI and A1C were significantly reduced by preoperative weight loss in gynaecologic oncology patients with T2D. There was a low rate of diabetes remission, with most patients having clinical characteristics predictive of a low likelihood of remission.

PMID:42145191 | DOI:10.1080/01443615.2026.2665632

Biometrics. 2026 Apr 9;82(2):ujag070. doi: 10.1093/biomtc/ujag070.

ABSTRACT

Extracting biologically meaningful information from high-dimensional, heterogeneous omics data is one of the key challenges in many biomedical studies. Among various biomedical applications, disease subtyping is of particular interest due to its critical role in improving diagnosis and designing personalized treatments. To address this, biclustering has become a widely used statistical method for subtyping. Additionally, it has been demonstrated across various statistical learning methods that incorporating biological graph knowledge such as gene regulatory network can significantly enhance variable selection, prediction accuracy, and model interpretability. However, existing graph-guided methods, while often yielding promising results, tend to overlook potential misspecifications, such as false positive (FP) and false negative (FN) edges in the graphs. Ignoring this noise can lead to suboptimal identification of biclusters. Therefore, it is essential to develop biclustering methods that can effectively handle noisy graphs as well as provide biological insight. We propose a Bayesian denoising knowledge-guided biclustering method that enables to integrate multiple graphs simultaneously. The incorporated graphs, viewed as noisy variations of the underlying true graph, are de-noised through modeling of FP and FN errors. A Markov chain Monte Carlo algorithm is developed to estimate the biclusters. Extensive simulation studies and real data analyses, including gene expression and proteomics datasets of Alzheimer’s disease, have been conducted to validate the superior performance of the proposed method.

PMID:42145180 | DOI:10.1093/biomtc/ujag070

Biometrics. 2026 Apr 9;82(2):ujag082. doi: 10.1093/biomtc/ujag082.

ABSTRACT

A concentration index, a standardised covariance between a health variable and relative income ranks, is often used to quantify income-related health inequalities. There is a lack of formal approach to study the effect of an exposure, e.g., education, on such measures of inequality. In this paper we contribute by filling this gap and developing the necessary theory and method. Thus, we define a counterfactual concentration index for different levels of an exposure. We give conditions for the identification of this complex estimand, and then deduce its efficient influence function. This allows us to propose estimators, which are regular asymptotic linear under certain conditions. In particular, we show that these estimators are $sqrt{n}$-consistent and asymptotically normal, as well as locally efficient. The implementation of the estimators is based on the fit of several nuisance functions. The estimators proposed have rate robustness properties allowing for convergence rates slower than $sqrt{n}$-rate for some of the nuisance function fits. The relevance of the asymptotic results for finite samples is studied with simulation experiments. We also present a case study of the effect of education on income-related health inequalities for a Swedish cohort.

PMID:42145179 | DOI:10.1093/biomtc/ujag082

J Contemp Dent Pract. 2026 Feb 1;27(2):190-200. doi: 10.5005/jp-journals-10024-4028.

ABSTRACT

AIM: To systematically review studies to evaluate the correlation and agreement between facial photographic measurements and cephalometric parameters in assessing jaw discrepancy.

MATERIALS AND METHODS: An extensive search was performed in PubMed, Scopus, and Web of Science to retrieve articles published from January 2015 to December 2024, and the literature search itself was conducted from 2 to 20 December 2024. The systematic review was carried out following the PRISMA 2020 guidelines. The participants, intervention, control, and outcome (PICO) framework used was as follows: (P) Orthodontic patients who underwent cephalometric and facial photographic assessment; (I): Cephalometric measurements derived from standardized 2D lateral facial photographs; (C): Cephalometric measurements obtained from lateral cephalograms; (O): Agreement between photographic and cephalometric parameters, evaluated through correlation coefficient, agreement statistics, or diagnostic accuracy measures (sensitivity/specificity); and (S): Observational correlation studies and diagnostic accuracy studies. The data extracted comprised study design, participant details, measurement parameters, and outcome statistics. Data extraction and quality appraisal were performed independently by two reviewers using the Joanna Briggs Institute (JBI) diagnostic test accuracy checklist.

RESULTS: A total of 83 studies were screened, of which seven studies met the inclusion criteria, comprising six cross-sectional and one prospective design. Risk of bias (ROB) assessment indicated an overall low to moderate risk. Most studies reported clear inclusion criteria and applied both index and reference tests within the same session. However, blinding of assessors was frequently unclear, introducing potential interpretation bias. Photographic measurements showed significant correlations with cephalometric parameters, with reliability highest for vertical dimensions and selected sagittal measures. Diagnostic accuracy ranged from fair to excellent. Transverse discrepancies were not assessed in any of the studies reviewed.

CONCLUSION: Standardized facial photographs can serve as a valuable adjunct in orthodontic assessment, particularly for evaluating sagittal and vertical relationships. Although facial photographs demonstrate diagnostic utility, comprehensive assessment of skeletal discrepancies continues to rely on lateral cephalograms.

CLINICAL SIGNIFICANCE: Facial photography provides a practical, radiation-free tool that may enhance orthodontic diagnosis in selected contexts, especially when radiographic imaging is unavailable. Its greatest utility lies in sagittal and vertical assessment, while future integration with 3D photogrammetry and AI-based landmark detection may further improve diagnostic precision. How to cite this article: Novianty SI, Alhasyimi AA, Dewi AH, et al. Facial Photography vs Cephalometry for Assessing Jaw Discrepancies: A Systematic Review. J Contemp Dent Pract 2026;27(2):190-200.

PMID:42145169 | DOI:10.5005/jp-journals-10024-4028

J Contemp Dent Pract. 2026 Feb 1;27(2):170-178. doi: 10.5005/jp-journals-10024-4022.

ABSTRACT

AIM: To compare the clinical efficacy of injectable vitamin C and injectable platelet-rich fibrin (i-PRF), each combined with microneedling (MN), in enhancing gingival thickness (GT) among individuals with a thin gingival phenotype.

MATERIALS AND METHODS: This randomized, controlled, split-mouth clinical trial included 16 systemically healthy participants (14 females, 2 males; 18-40 years) presenting with a thin gingival phenotype. In each patient, one side received MN + vitamin C (intervention), and the contralateral side received MN + i-PRF (control). Interventions were performed in three sessions at 7-day intervals. Clinical parameters-GT, keratinized tissue width (KTW), pocket depth (PD), gingival index (GI), and plaque index (PI)-were recorded at baseline, 1, 3, and 6 months. Data were analyzed using two-way repeated measures ANOVA and mixed cumulative linked models (CLMs), with p < 0.05 considered significant.

RESULTS: Both groups showed a statistically significant increase in GT over time (p < 0.001). The vitamin C group achieved significantly greater GT at 1 month (1.71 ± 0.29 vs 1.55 ± 0.35 mm; p = 0.007) and 3 months (1.39 ± 0.33 vs 1.26 ± 0.33 mm; p = 0.034), while differences were not significant at 6 months. Keratinized tissue width changes were minimal and comparable between groups. Pocket depth decreased slightly in both groups, with i-PRF showing a significantly lower PD at 6 months (p = 0.040). Both GI and PI improved significantly over time, with vitamin C showing a trend toward greater GI reduction (p = 0.053). No adverse effects were observed, and 92.3% of participants reported high satisfaction.

CONCLUSION: Injectable vitamin C combined with MN is a safe, minimally invasive, and effective approach for improving GT and esthetics in thin periodontal phenotypes, showing comparable long-term outcomes to i-PRF.

CLINICAL SIGNIFICANCE: Development of newer, less invasive therapeutic approaches that help in the prevention of gingival recession. A thin gingival biotype is more prone to gingival recession and to achieve satisfactory therapeutic results with minimum trauma to tissues of any interventional process. How to cite this article: Abdelhay NM, Elzanaty MT, Ibrahim RO. Comparative Evaluation of Vitamin C and Injectable Platelet-rich Fibrin in the Management of Thin Gingival Phenotype: A Split-mouth Randomized Clinical Trial. J Contemp Dent Pract 2026;27(2):170-178.

PMID:42145166 | DOI:10.5005/jp-journals-10024-4022

J Contemp Dent Pract. 2026 Feb 1;27(2):156-162. doi: 10.5005/jp-journals-10024-4032.

ABSTRACT

BACKGROUND AND AIM: Localization of submerged cover screws during second-stage dental implant surgery may require blind probing or extensive flap reflection, potentially increasing tissue trauma and postoperative discomfort. Implant detector devices (IDDs) have recently emerged as chairside adjuncts for implant localization; however, patient-reported outcomes associated with their clinical use remain underexplored. Therefore, this study aimed to evaluate patient-reported outcomes associated with different IDDs during second-stage dental implant surgery.

METHODOLOGY: A prospective observational study was conducted across multiple clinical settings. Adult patients undergoing second-stage exposure of submerged dental implants were consecutively recruited. Implant localization was performed using one of three detector systems (EasyinSmile, Implant Locator iD1, or Spotter) prior to soft-tissue incision. Immediately after surgery, participants completed a structured questionnaire assessing satisfaction, perceived complications, comfort with device use, perceived pain reduction, and willingness to recommend the technology. Associations between detector type and patient-reported outcomes were analyzed using cross-tabulation and Fisher’s exact test (α = 0.05).

RESULTS: Fifty-four patients were included. Overall satisfaction was high (87.0%, n = 47): 35 (64.8%) were very much satisfied, 12 (22.2%) somewhat satisfied, 7 (13.0%) undecided, and none selected either “not really satisfied” or “not at all satisfied.” Most participants reported comfort with device use (77.8%, n = 42), and 49 (90.7%) perceived less pain during the detector-assisted procedure. No definite complications were reported, although 15 (27.8%) were unsure. Thirty-three participants (61.1%) indicated willingness to recommend the technology. No statistically significant differences were observed among the three detector systems for any patient-reported outcome (p > 0.05).

CONCLUSION: Implant detector devices were associated with high patient-reported satisfaction and a favorable procedural experience during second-stage implant surgery. Outcomes appeared comparable across detector systems; however, because this observational study did not include a conventional control group, superiority over standard localization methods cannot be inferred. Further randomized controlled studies with objective outcomes are needed to confirm these findings.

CLINICAL SIGNIFICANCE: Implant detector devices may support a more patient-centered second-stage implant procedure by enabling minimally invasive implant uncovering, improving patient comfort and acceptance, and potentially reducing procedural anxiety. How to cite this article: Hamdi BA, AlZarea B, AlMoaleem MM, et al. Patient-reported Outcomes of Implant Detector Device Use in Second-stage Dental Implant Surgery. J Contemp Dent Pract 2026;27(2):156-162.

PMID:42145164 | DOI:10.5005/jp-journals-10024-4032

J Contemp Dent Pract. 2026 Feb 1;27(2):148-155. doi: 10.5005/jp-journals-10024-4029.

ABSTRACT

AIM: To evaluate the effect of over-the-counter (OTC) whitening products on postbleaching enamel surface roughness and the ability to recover the postbleaching shade after a standardized staining challenge under in vitro conditions.

MATERIALS AND METHODS: This experimental, longitudinal in vitro study included 40 human enamel specimens. Specimens were subjected to bleaching with 35% hydrogen peroxide (HP) and then immersed in a purple-corn beverage at 37°C for 30 minutes every 24 hour for 28 days; the beverage was renewed daily. Specimens were randomly assigned to four equal groups (n = 10) according to the OTC treatment: Group I, distilled water (control); group II, whitening strips (WS); group III, whitening mouthwash (WM); and group IV, WS + WM. Shade recovery was assessed using the CIEDE2000 color difference (ΔE₀₀) relative to the postbleaching reference shade, and surface roughness (Ra) was measured with a contact profilometer at baseline (post-staining, pre-OTC) and after the assigned OTC regimen. Statistical analyses included paired Student’s t-tests, MANOVA, and one-way between-groups ANOVA (p < 0.05).

RESULTS: At baseline, no between-group differences were observed for Ra (p = 0.893) or ΔE₀₀ (p = 0.304). After exposure, Ra increased significantly compared with control in WS (p = 0.026), WM (p = 0.002), and WS + WM (p = 0.025), with no differences among the three OTC regimens (p > 0.05). Within groups, Ra increased in WS (+0.83 μm; p < 0.001), WM (+1.18 μm; p = 0.001), and WS + WM (+0.72 μm; p = 0.005), but not in the control (p = 0.532). For ΔE_00, there were between-group differences (p < 0.001): WS + WM yielded the lowest values and differed from control, WS, and WM (all p < 0.05), while WS and WM did not differ from each other (p > 0.05). Within groups, ΔE₀₀ decreased in WS (-14.62; p < 0.001), WM (-16.47; p < 0.001), and WS + WM (-21.19; p < 0.001), with no change in the control (p = 0.292). A global multivariate effect of OTC whitening was detected [Wilks’ Λ, p < 0.001; partial η² (η_p²) = 0.753], with a very large effect size for ΔE₀₀ (η_p² = 0.934) and a moderate one for Ra (η_p² = 0.326).

CONCLUSION: Under in vitro conditions, OTC whitening regimens increased enamel surface roughness and reduced color difference, with a larger effect on ΔE₀₀ than on Ra. The combined regimen of strips and mouthwash produced the greatest reduction in ΔE_00, while Ra did not differ among OTC protocols. Longer-term randomized clinical trials are needed to determine the clinical relevance of these findings.

CLINICAL SIGNIFICANCE: After professional bleaching, OTC WS, WM, or both may improve color recovery, but they may also increase enamel surface roughness. Clinicians should advise patients about this esthetic-surface trade-off and recommend judicious use. How to cite this article: Llancari-Alonzo R, Manrique-Guzmán J, Manrique-Chávez J, et al. Effect of Over-the-counter Whitening Products on Postbleaching Enamel Surface Roughness and Shade Recovery: An In Vitro Study. J Contemp Dent Pract 2026;27(2):148-155.

PMID:42145163 | DOI:10.5005/jp-journals-10024-4029

J Contemp Dent Pract. 2026 Feb 1;27(2):141-147. doi: 10.5005/jp-journals-10024-4033.

ABSTRACT

AIM: This study investigated the effect of adding bioactive biocompatible seashell-derived hydroxyapatite (HA) nanofillers on the mechanical properties of acrylic polymethyl methacrylate (PMMA) resin, namely flexural strength, hardness, and compressive strength.

MATERIALS AND METHODS: Sixty acrylic specimens were divided into four groups, with five acrylic specimens for each test; control and experimental specimens containing 5, 10, and 12% seashell nanoparticles (NPs) added to the acrylic. The tests included hardness, compression strength, and flexural strength. According to the required proportion of NPs, these NPs were added to the monomer (liquid) of the cold-cured acrylic resin. The specimens were removed to complete the preparation process and then stored in distilled water at 37°C for 48 hours before testing. Data were analyzed using SPSS software. The difference was considered statistically significant at a p-value ≤ 0.05. For descriptive analysis of all variables, a paired t-test was used to compare the control group with the experimental groups.

RESULTS: For hardness and compression strength, the highest mean values for the groups were 12, 10, and 5%, respectively. For flexural strength, the 12% group was higher than the control group, followed by the 10% group, and then the 5% group, which was lower than the control group. A significant difference was found between the control group at both 5 and 12% for flexural strength, and a significant difference was also found between the control group at both 5 and 10% for hardness, and across all concentration groups for compression.

CONCLUSION: Adding a high concentration of seashell HA NP largely increased the flexural strength of PMMA resin. Cold-cured PMMA resin incorporated with lower concentrations of seashell HA NPs noticeably revealed improved hardness. Seashell HA NPs at the studied three concentrations improved the compression strength of the cold-cured PMMA resin.

CLINICAL SIGNIFICANCE: Natural HA NPs from seashell can be used as a bio-compatible nanofiller that can strengthen self-curing polymer materials. How to cite this article: Al Hamdany AK, Tawfek ZS, Agha NF, et al. Effect of Hydroxyapatite Seashell Nanofiller on Some Properties of Autopolymerized Acrylic Material for Orthodontic Appliances. J Contemp Dent Pract 2026;27(2):141-147.

PMID:42145162 | DOI:10.5005/jp-journals-10024-4033

J Contemp Dent Pract. 2026 Feb 1;27(2):124-129. doi: 10.5005/jp-journals-10024-3914.

ABSTRACT

AIM: The study aimed to characterize the surface morphology and evaluate the surface roughness of clear aligners (CAs) coated with titanium dioxide (TiO₂) nanoparticles.

MATERIALS AND METHODS: In this in vitro study, thermoformed PETG samples (n = 20) were equally divided into TiO₂-coated and noncoated groups. Coated samples underwent TiO₂ nanoparticle deposition via radiofrequency (RF) magnetron sputtering. All samples were analyzed using scanning electron microscopy (SEM) for surface morphology, energy dispersive X-ray analysis (EDAX) for elemental composition, and atomic force microscopy (AFM) for surface roughness. Parameters assessed included average surface roughness (Ra), root mean square roughness (Rms), and mean peak height (mh). Statistical analysis was performed using SPSS v22.0; intergroup comparisons were made using the independent t-test.

RESULTS: Scanning electron microscopy images showed a uniform, crack-free TiO₂ coating in the coated group, while the control group lacked such features. Energy dispersive X-ray analysis confirmed the presence of titanium and oxygen in the coated samples only. Atomic force microscopy results revealed significantly lower surface roughness values in the coated group: Ra (5.17 ± 1.28 nm), Rms (6.77 ± 1.62 nm), mh (36.11 ± 9.27 nm) compared to the control: Ra (11.96 ± 5.80 nm), Rms (14.72 ± 6.30 nm), mh (51.00 ± 7.42 nm) (p < 0.05).

CONCLUSION: Titanium dioxide-coated aligners demonstrated reduced surface roughness and improved surface morphology over non-coated aligners.

CLINICAL SIGNIFICANCE: Titanium dioxide nanoparticle coating may enhance the clinical performance of CAs by improving surface quality and reducing potential bacterial adhesion. How to cite this article: Padmanabhan SV, Kalathur Sridev A, Sankaranarayanan V, et al. In Vitro Evaluation of Surface Morphology and Roughness of TiO₂-coated Clear Aligners Using Scanning Electron Microscopy and Atomic Force Microscopy. J Contemp Dent Pract 2026;27(2):124-129.

PMID:42145160 | DOI:10.5005/jp-journals-10024-3914