Table 1.
Characteristics and detailed description of the included studies.
| S. No. | Author Name/Year/Country | Study Design | Sample Size | Study Groups | Type of Toothbrushes | Duration of Use of Toothbrushes | Method of DNA Extraction | Gene(s) Assessed with Amplification Method | Capillary Electrophoresis Instrument | Results | Inference/Statistical Significance |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Alfadaly et al./2016/Saudi Arabia | Observational cross-sectional study | Total number of patients: 25; Total number of toothbrushes: 104; (25 uncovered siwaks, 4 covered siwaks, and 25 toothbrushes) |
Group I (4 months, 4 volunteers); Group II (3 months, 5 volunteers); Group III (2 months, 4 volunteers); Group IV (1 month, 5 volunteers); Group V (1 week, 3 volunteers); Group VI (the same day, 4 volunteers, and covered siwak was added); Group VII (reference samples); Group VIII (positive and negative control samples) |
Toothbrush, uncovered siwak, and covered siwak | 1 week, 1 month, 2 months, 3 months, and 4 months | Promega kit | DNA profiling: AmpFLSTR Identifiler PCR Amplification Kit |
3130XL Genetic Analyzer and GeneMapper software | DNA from siwak samples (18.96 ± 16.15) was higher than toothbrush samples (1.76 ± 1.07). 1/25 samples in siwak only partial DNA profiling could be done. In toothbrush group 8/25 profiling could be done and 3/25 partial profiling was done. Unit of DNA measurement was ng/μL |
Significant (p < 0.001%) |
| 2. | Reddy et al./2011/India | Observational cross-sectional study | 30 samples, 30 patients (each used a sample for a week). Equal gender distribution in each group |
Group 1: 10 samples immediately processed; Group II: 10 samples processed after 1 month; Group III: 10 samples processed after 2 months |
Toothbrush brand name not mentioned | Immediately, 1 month, and 2 months | Real Genomics YGB 100 (Real Biotech Corporation, Taiwan) DNA extraction kit | SRY gene for gender identification using real-time PCR and Taq PCR Master Mix (Qiagen, India) | Real Plex Master Cycler (Eppendorf, Japan) | Genetic material was preset in low quantity in most of the samples. Gender identification: All males were identified correctly; out of 15 females, 4 were wrongly identified. Unit of DNA measurement was ng/μL |
Sensitivity of SRY gene was 100%. Specificity of SRY gene in gender was 73.33% |
| 3. | Riemer et al./2012/Canada | Observational cross-sectional study | N = 55 (25 males and 30 females) |
Group I: 21 individuals used their toothbrush for 1 month; Group II: 22 individuals used their toothbrush for 3 months; Group II: 12 individuals gave their currently used toothbrush for analysis. Negative control: 2 unused toothbrushes |
Toothbrush brand name not mentioned | Current used toothbrush, 1 month, and 3 months | Partial toothbrush head sampling technique phenol-chloroform method, and profiles were obtained using AmpFISTR Profiler Plus (Applied Biosystems, Foster City, CA) |
DNA profile compared with reference standard AmpFISTR Profiler Plus PCR Identification Kit (Applied Biosystems, Foster City, CA) |
No data available | DNA yield: 600 ng of DNA per toothbrush. DNA profiling complete in 51 and partial in 4 samples. Unit of DNA measurement was ng/g |
No significant difference in the quantity and quality of DNA obtained from 1 month, 3 months, and random period used toothbrushes |
| 4. | Tanaka et al./2000/Japan | Observational cross-sectional study | 10 toothbrushes from 10 individuals | Case toothbrush samples (among 10 samples, 3 were actual cases: 1 drowned patient and 2 from murder case). Control: blood samples from 8 patients (blood samples from the heart of both the drowning and homicide victims were obtained at autopsy) |
Used toothbrush | 3 months to 1 year. Among 10 samples, 1 was stored for 6 months before analysis |
Whole toothbrush head was taken for DNA extraction by phenolchloroform extraction and ethanol precipitation. Quantification by fluorometry |
Six loci (DQA1, LDLR, GYPA, HBGG, D7S8, and GC); Nine STR loci (D3S1358, vWA, FGA, TH01, TPOX, CSF1PO, D5S818, D13S317, and D7S820). AmpFISTR Profiler Plus PCR Amplification Kit (Applied Biosystems, Foster City, CA) |
310 Genetic Analyzer (Applied Biosystems, Foster City, CA) | 9 toothbrushes: 10 to 430 ng; 10 toothbrushes: 0.5 ng mL. All loci were types in all samples despite low DNA yield. Unit of DNA measurement was ng/μL |
All the test samples were typed at all loci. (No statistical analysis was performed) |
| 5. | Bandhaya et al./2007/Thailand | Observational cross-sectional study | Total samples obtained from 4 individuals who used toothbrushes for 1, 7, 14, or 30 days |
Group 1: toothbrush used for 1 day; Group 2: toothbrush used for 7 days; Group 3: toothbrush used for 14 days; Group 4: toothbrush used for 30 days. Each group had the following subgroups: Sub group a1: 5 bristle bundles DNA extraction done by Chelex1-100; Sub group a2: 5 bristle bundles DNA extraction done by QIAamp DNA Mini Kit; Subgroup b1: 10 bristle bundles DNA extraction done by Chelex1-100; Sub group b2: 5 bristle bundles DNA extraction done by QIAamp DNA Mini Kit |
Used toothbrushes | 1, 7, 14, and 30 days | Chelex1-100 or QIAamp DNA Mini Kit | STR (GeneAmp PCR System 9700) (Applied Biosystems) | ABI PRISM 3100 Genetic Analyzer and GeneMapper ID Software (Applied Biosystems) | DNA from QIAamp DNA Mini Kit > DNA from Chelex1-100 kit. Complete profile could be typed from QIAamp DNA Mini Kit but not in Chelex1-100 kit. Comparing 5 and 10 bristle bundles, STR was complete in all samples of Mini Kit from 5 bristle bundles and was complete in 30- and 14-day samples of 10 bristle bundles of Mini Kit. In the Chelex1-100 kit, none was completely typed. Unit of DNA measurement was ng/μL |
Statistical analysis was not done. DNA Mini Kit was a better method for DNA extraction and 5 bristle bundles are better suited for DNA extraction from toothbrushes |