CBCT based study to analyze and classify root canal morphology of maxillary molars - A retrospective study

OBJECTIVE

The study aims to evaluate maxillary molars' root and root canal morphology among the Saudi population using Cone-Beam Computed Tomography scanning (CBCT).

SUBJECTS AND METHODS

Retrospectively, the CBCT scans of 483 Saudi nationals were evaluated to identify the number of roots and root canals in maxillary first and second molars. The records were tabulated and classified according to Vertucci and a new system for root and canal classification given by Ahmed and Dummer. Fisher's exact test was used to analyze the data statistically. To check for symmetry, comparisons were made between all the maxillary first molars (MFM's) and maxillary second molars (MSM's) on opposing quadrants. Inter Observer variability was seen using Cohen's Kappa test.

RESULTS

MFM's presented with three roots with Type II Vertucci canal configuration (VC) commonly seen among them. MSM's had more variations in the number of roots and canals, although three roots and Type I VC were predominantly seen. When comparing the two genders statistically significant difference was observed in both maxillary molars at a 5% level using Fisher's exact test. Three roots with four canals (3R4C) were predominantly observed in the MFM's (85.6%) and three roots with three canals (3R3C) identified in 51.95% were more common than 3R4C (43.55%) in MSM's. Both the maxillary molars bilaterally, exhibited a high percentage of symmetry in root and canal configurations.

CONCLUSIONS

Identification of root canal morphology of molars would reduce the chances of root canal failures by making sure all canals are obturated. This study provides supplemental information about the root canals of maxillary molars in a Saudi Arabian subpopulation.

Awareness, knowledge, attitudes, and practices before the second wave of the COVID-19 pandemic in Saudi Arabia

OBJECTIVE

The COVID-19 outbreak was first reported in Wuhan City, China in early December 2019. It was declared a pandemic by WHO in March 2020. This study aimed at assessing the knowledge, awareness, and attitudes of the general population in Saudi Arabia towards COVID-19, as well as its adherence to preventive measures and its willingness to take the vaccine.

PATIENTS AND METHODS

This descriptive cross-sectional study involved an online sample of 7,188 participants (from five regions of Saudi Arabia) who completed a self-administered online-based questionnaire. They were recruited from 23 November 2020 to 29 November 2020 based on the nonprobability convenience sampling method. The self-administered questionnaire comprised four main sections: gathering information about participants' demographics, knowledge and awareness of COVID-19, participants' practices (hygiene and other) against infection, and vaccine acceptability.

RESULTS

More than half of the study participants were knowledgeable about COVID-19. The mean scores were 10.4 (SD=3.44, range: 0-18 - with high scores indicating better knowledge or awareness) for knowledge and 6.1 (SD=2.26, range: 0-11) for awareness, indicating a need for more educational campaigns to improve the level of knowledge and awareness among the Saudi Arabian population about COVID-19. The mean score for attitude was 5 (SD=1.67, range: 0-8 - from 0=very pessimistic to 8=very optimistic), indicating moderate optimism. As for practices, the mean score was 7.8 (SD=1.57, range: 0-10), indicating good practices to prevent or control infection. Concerning acceptability of the COVID-19 vaccine, 63.8% of the participants agreed to take the vaccine if it was proven to be 95% effective.

CONCLUSIONS

The findings of this study can help us designing effective measures against COVID-19 infections. Our results highlight the best practices adopted by the Saudi Arabian population, as well as those areas requiring improvement, including knowledge, attitudes, and practices against this disease.

Clinical genomics expands the morbid genome of intellectual disability and offers a high diagnostic yield

Intellectual disability (ID) is a measurable phenotypic consequence of genetic and environmental factors. In this study, we prospectively assessed the diagnostic yield of genomic tools (molecular karyotyping, multi-gene panel and exome sequencing) in a cohort of 337 ID subjects as a first-tier test and compared it with a standard clinical evaluation performed in parallel. Standard clinical evaluation suggested a diagnosis in 16% of cases (54/337) but only 70% of these (38/54) were subsequently confirmed. On the other hand, the genomic approach revealed a likely diagnosis in 58% (n=196). These included copy number variants in 14% (n=54, 15% are novel), and point mutations revealed by multi-gene panel and exome sequencing in the remaining 43% (1% were found to have Fragile-X). The identified point mutations were mostly recessive (n=117, 81%), consistent with the high consanguinity of the study cohort, but also X-linked (n=8, 6%) and de novo dominant (n=19, 13%). When applied directly on all cases with negative molecular karyotyping, the diagnostic yield of exome sequencing was 60% (77/129). Exome sequencing also identified likely pathogenic variants in three novel candidate genes (DENND5A, NEMF and DNHD1) each of which harbored independent homozygous mutations in patients with overlapping phenotypes. In addition, exome sequencing revealed de novo and recessive variants in 32 genes (MAMDC2, TUBAL3, CPNE6, KLHL24, USP2, PIP5K1A, UBE4A, TP53TG5, ATOH1, C16ORF90, SLC39A14, TRERF1, RGL1, CDH11, SYDE2, HIRA, FEZF2, PROCA1, PIANP, PLK2, QRFPR, AP3B2, NUDT2, UFC1, BTN3A2, TADA1, ARFGEF3, FAM160B1, ZMYM5, SLC45A1, ARHGAP33 and CAPS2), which we highlight as potential candidates on the basis of several lines of evidence, and one of these genes (SLC39A14) was biallelically inactivated in a potentially treatable form of hypermanganesemia and neurodegeneration. Finally, likely causal variants in previously published candidate genes were identified (ASTN1, HELZ, THOC6, WDR45B, ADRA2B and CLIP1), thus supporting their involvement in ID pathogenesis. Our results expand the morbid genome of ID and support the adoption of genomics as a first-tier test for individuals with ID.

Excessively redundant umbilical skin as a potential early clinical feature of Morquio syndrome and FKBP14-related Ehlers-Danlos syndrome

Several umbilical abnormalities have been linked to and utilized to aid in the clinical diagnosis of certain syndromes. For instance, umbilical skin redundancy has long been recognized as a core feature of Rieger syndrome although its association with other disorders is unknown. In this article, we report for the first time the occurrence of this distinct clinical sign in association with two other syndromes: Morquio syndrome and FKBP14-related Ehlers-Danlos syndrome (EDS). Our observation is clinically significant because patients with Morquio syndrome are often diagnosed only after they develop typical skeletal manifestations, which reduces the efficacy of available enzyme replacement therapy, so the umbilical sign we report here can facilitate a much earlier diagnosis. In addition, the extreme rarity of FKBP14-related Ehlers-Danlos syndrome (EDS) can greatly delay the diagnosis of this condition unless it is recognized in the differential diagnosis of redundant umbilical skin as we argue in this report.

Free thyroxine, free triiodothyronine and thyroid-stimulating hormone before and after hemodialysis in Saudi patients with end-stage renal disease: is there any difference?

Patients on regular hemodialysis (HD) suffer from a chronic illness that is believed not to involve the thyroid gland. However, they may have low levels of serum thyroxine (T4) and tri-iodothyronine (T3). It was found earlier that serum total T3 and free T4 concentrations were significantly higher immediately after a HD session than before. In this single-center prospective study, we evaluated the difference between free T3 (FT3), free T4 (FT4) and thyroid-stimulating hormone (TSH) levels before and immediately after HD sessions in 40 Saudi patients with end-stage renal disease undergoing regular HD at the Prince Salman Center for Kidney Disease, Riyadh, Saudi Arabia. The study involved 23 female and 17 male patients with a mean age of 49.65 ± 16.20 years. None of the study patients had any known thyroid disease. We measured the thyroid hormones monthly for three successive months using the electrochemiluminescence technique both before and after HD sessions. At the end of our study, we found a statistically significant difference between pre-HD and post-HD levels for FT3; in the first month, it was 4.47 ± 1.01 versus 4.86 ± 1.03 pmol/L, (P = 0.004); in the second month, it was 4.48 ± 1.37 versus 4.83 ± 1.64 pmol/L, (P = 0.008); and in the third month, it was 3.84 ± 0.88 versus 4.04 ± 0.84 pmol/L, (P = 0.003). The FT4 in the first month was 15.42 ± 2.75 pmol/L versus 17.20 ± 2.85 pmol/L, P = 0.000, in the second month it was 14.86 ± 2.66 versus 16.74 ± 3.27 pmol/L, P = 0.000 and in the third month it was 14.86 ± 3.93 versus 16.70 ± 4.00 pmol/L, P = 0.000, respectively. However, the pre- and post-HD levels of TSH did not show any statistically significant difference; in the first month it was 3.17 ± 1.47 versus 3.32 ± 1.39 pmol/L, P = 0.254, in the second month it was 2.57 ± 1.36 versus 2.49 ± 1.29 pmol/L, P = 0.299 and in the third month it was 2.36 ± 1.17 versus 2.44 ± 1.22 pmol/L, P = 0.238, respectively. Thus, there was a statistically significant increase in the post-HD levels of FT3 and FT4 although the TSH levels did not show any significant change. Our study suggests that measurement of TSH alone might be more reliable in the assessment of thyroid function in patients on regular HD than FT3 and FT4.

Molecular characterization of retinitis pigmentosa in Saudi Arabia

PURPOSE

To catalog mutations that underlie retinitis pigmentosa (RP) in Saudi Arabia using a representative sample.

METHODS

Fifty-two patients with RP were recruited and their homozygosity mapping, with or without linkage analysis, was used to suggest the causative genes followed by bidirectional sequencing.

RESULTS

Mutations were identified in 94% of our study cohort, including seven that were novel.

CONCLUSIONS

Homozygosity mapping is an extremely robust approach in the study of retinitis pigmentosa in the setting of high rates of consanguinity. BBS3 mutations can rarely present as nonsyndromic RP.