Relationship between hypothyroidism and periodontitis: A scoping review

Periodontitis and thyroid function: A bidirectional Mendelian randomization study

BACKGROUND AND OBJECTIVE

Previous studies suggest interaction between periodontitis and thyroid function, while the causality has not yet been established. We applied the Mendelian randomization (MR) method to assess bidirectional causal association between periodontitis and thyroid-related traits, including free thyroxine (FT4), thyroid stimulating hormone (TSH), hypothyroidism, hyperthyroidism and autoimmune thyroid disease (AITD).

METHODS

Genetic instruments were extracted from large-scale genome-wide association studies on normal-range FT4 (N = 49 269) and TSH (N = 54 288) levels, TSH in full range (N = 119 715); hypothyroidism (discovery/replication cohorts: N = 53 423/334 316), hyperthyroidism (discovery/replication cohorts: N = 51 823/257 552), AITD (N = 755 406) and periodontitis (N = 45 563). Here, the inverse variance weighted (IVW) method was applied as the primary analysis, and robustness of results were assessed by several pleiotropic-robust methods. Results were adjusted for Bonferroni correction thresholds with significant p < .004 (0.05/13) and suggestive p between .004 and .05.

RESULTS

The IVW analysis revealed a suggestively causal linkage between genetic predisposition to periodontitis and the increased risk of hypothyroidism (discovery cohort: odds ratio [OR] = 1.24, 95% confidence interval [CI] = 1.05-1.46, p = .012; replication cohort: OR = 1.06, 95% CI = 1.01-1.11, p = .011). No evidence was found for supporting the impact of periodontitis on hyperthyroidism and AITD risks (associated p ≥ .209), as well as thyroid-related traits on periodontitis risk (associated p ≥ .105). These findings were robust and consistent through sensitivity analysis with other MR models.

CONCLUSION

This bidirectional MR reveals periodontitis should not be attributed to variations in thyroid function but it has potential causal effect on hypothyroidism risk, which provides a better understanding of the relationship between periodontitis and thyroid function, and potential evidence for the clinical intervention of hypothyroidism. Further investigations are warranted to elucidate the nature and underlying mechanisms of this finding.

Severe Chronic Gingivitis in Association With Hypothyroidism and Grade 2 Adenoid Hypertrophy: A Case Report

Hypothyroidism is the second-commonest endocrine disorder in the world. Similarly, gingivitis is also a highly prevalent oral condition in every population globally. Adenoid hypertrophy and associated mouth breathing may aggravate preexisting gingival inflammation. Here, we are presenting the case of a 22-year-old female gingivitis patient with bleeding from gums on the slightest provocation and with a two-year history of preexisting hypothyroidism. Thorough systemic examinations and investigations ruled out the presence of hematological and/or coagulation disorders. However, she was found to have grade 2 adenoid hypertrophy along with a habit of mouth breathing. Periodontal and systemic management of the patient has resolved her gingival bleeding to a greater extent. Still, there remain a lot of ambiguity and a lack of clarity about the exact etiology and mechanism of pathogenesis behind her oral and general health status. Cases like these pose a diagnostic challenge for the treating dentist or periodontist and thus require a coordinated and collaborative effort of multiple health specialties.

A Patient with Hypothyroidism in Need of Periodontal Connective Tissue Graft Surgery

Hypothyroidism is a condition characterized by thyroid hormone deficiency and can be caused by a variety of factors. Untreated or chronic hypothyroidism can present in adult patients as myxedema, which is characterized by symptoms including fatigue, generalized slower metabolism, weight gain, depressed mood, dry skin, and brittle hair. Hypothyroidism can have various oral manifestations, particularly in children, in whom it can delay the eruption of the dentition. Dental management of patients with hypothyroidism depends on the etiology and status of the disease and requires the consideration of other organ systems affected.

Investigating salivary concentration of calcium ion in hypothyroidism

Background and Aims

Hypothyroidism is the most common disease of the thyroid gland. Thyroid hormone plays a crucial role in regulating tissue growth and metabolism. Additionally, patients with thyroid dysfunction have a higher incidence of caries and periodontal problems. The presence of calcium and phosphate ions seems to be effective in remineralizing teeth and reducing caries. The aim of this study was to evaluate the salivary level of calcium in patients with hypothyroidism.

Results

The results of this study showed that saliva calcium concentration in patients with hypothyroidism is significantly lower than healthy subjects. Also, no significant association was found between salivary calcium levels and TSH and T4 hormones level of blood.

Conclusion

The increased prevalence of dental caries in patients with hypothyroidism may be related to a decrease in their calcium levels.

Unexpected lower level of oral periodontal pathogens in patients with high numbers of systemic diseases

Background

Periodontal disease is associated with systemic conditions such as diabetes, arthritis, and cardiovascular disease, all diseases with large inflammatory components. Some, but not all, reports show periopathogens Porphyromonas gingivialis and Tannerella forsythia at higher levels orally in people with one of these chronic diseases and in people with more severe cases. These oral pathogens are thought to be positively associated with systemic inflammatory diseases through induction of oral inflammation that works to distort systemic inflammation or by directly inducing inflammation at distal sites in the body. This study aimed to determine if, among patients with severe periodontal disease, those with multi-morbidity (or many chronic diseases) showed higher levels of periodontal pathogens.

Methods

A total of 201 adult subjects, including 84 with severe periodontal disease were recruited between 1/2017 and 6/2019 at a city dental clinic. Electronic charts supplied self-reported diseases and conditions which informed a morbidity index based on the number of chronic diseases and conditions present. Salivary composition was determined by 16S rRNA gene sequencing.

Results

As expected, patients with severe periodontal disease showed higher levels of periodontal pathogens in their saliva. Also, those with severe periodontal disease showed higher levels of multiple chronic diseases (multimorbidity). An examination of the 84 patients with severe periodontal disease revealed some subjects despite being of advanced age were free or nearly free of systemic disease. Surprisingly, the salivary microbiota of the least healthy of these 84 subjects, defined here as those with maximal multimorbidity, showed significantly lower relative numbers of periodontal pathogens, including Porphyromonas gingivalis and Tannerella Forsythia, after controlling for active caries, tobacco usage, age, and gender. Analysis of a control group with none to moderate periodontal disease revealed no association of multimorbidity or numbers of medications used and specific oral bacteria, indicating the importance of severe periodontal disease as a variable of interest.

Conclusion

The hypothesis that periodontal disease patients with higher levels of multimorbidity would have higher levels of oral periodontal pathogens is false. Multimorbidity is associated with a reduced relative number of periodontal pathogens Porphyromonas gingivalis and Tannerella forsythia.

DETERMINATION OF MANDIBULAR BONE CHANGES IN PATIENTS WITH PRIMARY HYPOTHYROIDISM TREATED WITH LEVOTHYROXINE SODIUM

Background

This study aimed to assess fractal dimension (FD) and the radiomorphometric indexes on the digital panoramic radiography (DPR) of patient with primary hypothyroidism receiving levothyroxine sodium replacement therapy.

Methods

A total of 115 subjects were included in this cross sectional retrospective study. According to the results of the thyroid function tests, the subjects were divided into two groups as primary hypothyroidism (levothyroxine sodium replacement therapy given), (n = 57) and the healthy control group (n = 58). The fractal dimension (FD), panoramic mandibular index (PMI), mandibular cortical width (MCW), gonial index (GI) and mandibular cortical index (MCI) values of all patients were calculated on DPRs. The statistical analysis of all data was performed with SPSS version 22.

Results

The distributions of age and gender in the primary hypothroidism group were similar to control group (p = 0.19 and p = 0.62, respectively). The two groups did not differ statistically significantly in terms of FD, PMI, MCW, GI, and MCI.

Conclusion

We determined that mandibular cortical and trabecular bone structure did not significantly differ between healthy individuals and patients receiving drug replacement theraphy due to hypothyroidism, but our results should be further supported with the investigation of clinical parameters.

Atypical antipsychotics olanzapine and clozapine increase bone loss in female rats with experimental periodontitis

BACKGROUND AND OBJECTIVES

Periodontitis is a highly prevalent disease in psychiatric patients, including those undergoing symptomatic treatment with second-generation antipsychotics. Some of these drugs, such as clozapine (CLO) and olanzapine (OLA), have prominent metabolic effects such as weight gain, hyperglycemia, and dyslipidemia, which are risk factors for periodontitis. In addition to the metabolic effects, there are reports of changes in salivary flow, gingival bleeding, and caries. In this context, we aimed to evaluate if the metabolic effects of OLA and CLO alter periodontal parameters in an animal model of periodontitis without the environmental and psychosocial biases inherent to human diseases.

METHODS

In the first set of experiments, male and female adult Wistar rats received oral administration of CLO, OLA, or vehicle for 45 days. They were evaluated for body mass composition and weight gain, blood glucose parameters (fasting and glucose tolerance and insulin resistance tests), and lipid profile (HDL, total cholesterol, and triglycerides). In a second set of experiments, the same measurements were performed in female rats exposed to the antipsychotics for 45 days and ligature-induced periodontitis on the 30th day of treatment. Macroscopic measurements of exposed roots, microtomography in the furcation region of the first molar, and histological evaluation of the region between the first and second molars were evaluated to assess bone loss. Additionally, gingival measurements of myeloperoxidase activity and pro-inflammatory cytokine TNF-α were made.

RESULTS

Only females exposed to OLA had more significant weight gain than controls. They also exhibited differences in glucose metabolism. Ligature-induced periodontitis produced intense bone retraction without changing the density of the remaining structures. The bone loss was even higher in rats with periodontitis treated with OLA or CLO and was accompanied by a local increase in TNF-α caused by CLO. These animals, however, did not exhibit the same metabolic impairments observed for animals without periodontitis.

CONCLUSION

The use of clozapine and olanzapine may be a risk factor for periodontal disease, independent of systemic metabolic alterations.

Reduction in Gingival Bleeding after Atelocollagen Injection in Patients with Hashimoto's Disease-A Pilot Study

Periodontal diseases are one of the main causes of tooth loss and the second most common oral disease after carries. Patients with autoimmune diseases, such as Hashimoto's disease, are more often vulnerable to infection. In the study group of patients, despite the lack of other signs of gingivitis, bleeding occurred after tooth brushing or minor trauma. Bleeding on probing is the first objective sign of ongoing inflammation. The study was conducted on a group of 17 patients diagnosed with Hashimoto's disease. The atelocollagen Linerase (100 mg) thinned with 5 mL 0.9% NaCl was used. A total of 0.05 mL of solution was injected into keratinized gingiva, two millimeters above the gingival papillae basement, four times in two-week intervals. The greatest decrease in the number of bleeding points was observed after the first and second injections of atelocollagen. After the third and fourth injections, the average BOP continued to decrease, but the decline was very slow. The use of atelocollagen made it possible to eliminate bleeding symptoms in the study group.

An Unusual Simultaneous Occurrence of Diabetes and Hypothyroidism in a Periodontitis Patient: A Case Report

Periodontal disease, diabetes mellitus, and hypothyroidism are commonly prevalent non-communicable diseases afflicting the human population all over the world, with the added burden on the health care system increasing the overall morbidity. It has been seen through various shreds of evidence that systemic diseases may influence the course of the localized disease and vice versa. Here, we report a case of 38-year-old female periodontitis patient also diagnosed with diabetes mellitus and hypothyroidism. Periodontitis is one of the complications of diabetes. But the occurrence of periodontal disease is a less common intra-oral finding in hypothyroidism as compared to diabetes. All these three chronic diseases were simultaneously observed in this patient, which is a rare occurrence and can adversely affect her overall prognosis. This case report highlights the need for a systematic interdisciplinary approach in the diagnosis and management of such cases.

Analysis of the Oral Microbiome in a Patient with Cardiofaciocutaneous Syndrome and Severe Periodontal Disease: Impact of Systemic Antibiotic Therapy

An 8-year-old girl diagnosed with cardiofaciocutaneous syndrome presented to our department with gingival pain, inflammation, and bleeding. Her medical history included hypoplasia of the corpus callosum, intellectual disability, trichothiodystrophy, global developmental delay, myopia, laryngomalacia, hypothyroidism, and osteoporosis. A diagnosis was reached of "periodontitis as a direct manifestation of systemic diseases". During 9 years of follow-up, there were exacerbation episodes with spontaneous gum bleeding, ulcers in the interdental papilla, tooth mobility, and progressive tooth loss. Some of these exacerbation episodes resolved clinically with the administration of amoxicillin and metronidazole. We therefore proposed an oral microbiome study (subgingival and saliva samples) before and after antibiotic therapy. The most abundant genera at the subgingival level before administering antibiotics were Prevotella, Streptococcus, Fusobacterium, Leptotrichia, and Aggregatibacter. Of the 94 genera sequenced, 57 were less abundant in the post-treatment state than at baseline, particularly certain Gram-negative periodontal pathogens such as Porphyromonas, Treponema, Aggregatibacter, Fusobacterium, and Campylobacter. In contrast, other genera related to oral health, such as Haemophilus, Granulicatella, and Abiotrophia, showed an increase after administering the antibiotic. In conclusion, periodontitis exacerbations as a direct manifestation of systemic disease can occasionally be controlled exclusively with systemic antibiotics, without the need for performing mechanical periodontal therapy. This clinical recovery is correlated to substantial changes in the oral microbiome, which lead to the recovery of eubiosis of the microbiota.

Osteoporosis and Alveolar Bone Health in Periodontitis Niche: A Predisposing Factors-Centered Review

Periodontitis is a periodontal inflammatory condition that results from disrupted periodontal host-microbe homeostasis, manifested by the destruction of tooth-supporting structures, especially inflammatory alveolar bone loss. Osteoporosis is characterized by systemic deterioration of bone mass and microarchitecture. The roles of many systemic factors have been identified in the pathogenesis of osteoporosis, including endocrine change, metabolic disorders, health-impaired behaviors and mental stress. The prevalence rate of osteoporotic fracture is in sustained elevation in the past decades. Recent studies suggest that individuals with concomitant osteoporosis are more vulnerable to periodontal impairment. Current reviews of worse periodontal status in the context of osteoporosis are limited, mainly centering on the impacts of menopausal and diabetic osteoporosis on periodontitis. Herein, this review article makes an effort to provide a comprehensive view of the relationship between osteoporosis and periodontitis, with a focus on clarifying how those risk factors in osteoporotic populations modify the alveolar bone homeostasis in the periodontitis niche.

Transcriptomic Analysis Reveals Genetic Cross-Talk between Periodontitis and Hypothyroidism

Background. Aim of this bioinformatics study based on transcriptomic analysis was to reveal the cross-talk between periodontitis (PD) and hypothyroidism (HT). Methods. The gene expression datasets GSE18152 and GSE176153 of HT and GSE10334, GSE16134, and GSE173078 of PD were downloaded through the Gene Expression Omnibus (GEO) database. Differential Expression Genes (DEG) between cases and controls in each microarray were assessed by using the “limma” (linear models for microarray data) R package (|log2 fold change (FC)| >0 and $P$ -value <0.05). To analyze the cross-talk effect between HT and PD, the intersection of DEG of HT and PD was selected. To investigate the biological function of cross-talk genes, the gene ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were applied. Protein-Protein Interaction (PPI) network was constructed using Cytoscape software. Top 10 cross-talk genes were screened, and the expression values of these 10 genes were extracted. ROC analysis was performed by using the pROC package and GGplot2 package of R language to predict the classification accuracy. Results. The overlapping DEG between HT and PD were 107 cross-talk genes. The results revealed that developmental process ( $P$ -value =1.06E-21) was the most significantly enriched biological process, followed by cell differentiation ( $P$ -value =8.49E-18) and immune system process ( $P$ -value =6.78E-11). KEGG analysis showed that Complement and coagulation cascades ( $P$ -value =2.29E-05), Hematopoietic cell lineage ( $P$ -value =2.66E-05), Phospholipase D signaling pathway ( $P$ -value =0.034367878) and Chemokine signaling pathway ( $P$ -value =0.04946333) were significantly enriched. The top 10 genes with most connections were LCE1B, LCE2B, LCE2A, LCE2C, LCE1C, LCE1F, ITGAM, C1QB, TREM2, and CD19. The AUC values of the two datasets of HT were both greater than 65% (GSE18152 = 81.42%, GSE176153 = 68.75%). AUC values of three datasets of PD were all greater than 60% (GSE10334 = 69.23%, GSE16134 = 73.72%, GSE173078 = 81.6%). Conclusions. A genetic cross-talk between HT and PD was detected, whereby LCE family genes appeared to play the most important role.

MORPHOLOGICAL CHANGES OF PERIODONTAL COMPONENTS UNDER EXPERIMENTAL LIPOPOLYSACCHARIDE PERIODONTITIS COMBINED WITH HYPERTHYROIDISM

OBJECTIVE

The aim: Investigate structural changes in the tissues of the periodontal complex under the condition of experimental lipopolysaccharide periodontitis combined with hyper¬thyroidism.

PATIENTS AND METHODS

Materials and methods: The studies were performed on adult white male rats, which simulated periodontitis combined with hyperthyroidism. Periodontal tissues were subjected to morphological examination on the 22nd day of the experiment. Collection of material for microscopic examinations was performed according to the generally accepted method; histological specimens were studied using a light optical microscope.

RESULTS

Results: Morphological studies of the components of the periodontal complex of experimental animals with experimental periodontitis established the reorganization of its structural elements. Damage to the epithelium in the area of attachment of the circular ligament and erosive-ulcerative changes of the gums led to a deepening of the gingival sulcus with the formation of a deep periodontal pocket. Intense hyperkeratosis was observed in the area of the bottom of the periodontal pocket. In the own plate of the mucous membrane of the gums - significant edema, collagen fibers were disorganized, defragmented. There were pronounced destructive-degenerative and inflammatory changes of the epithelial and own plates of all areas of the gums and periodontium, damage to the nuclei and cytoplasm of keratinocytes, fibroblasts, and leukocytes.

CONCLUSION

Conclusions: Experimental periodontitis combined with hyperthyroidism is accompanied by pronounced signs of destructive and inflammatory changes in the soft and dense tissues of the periodontal complex, as well as disruption of stromal-vascular interactions, which progress from reversible to irreversible disruption of periodontal connective tissue.

Implication of thyroid function in periodontitis: a nationwide population-based study

Possible links between periodontitis and various cardiometabolic and autoimmune diseases have been advocated on the basis of chronic inflammation or oxidative stress. However, the association between periodontitis and thyroid dysfunction is under-researched. Participants without previous thyroid disease or ongoing thyroid-related medication were included from a nationwide population-level survey. Participants were categorized into tertiles of thyroid stimulating hormone (TSH) levels (first tertile < 1.76 mIU/L; second tertile 1.76-2.83 mIU/L; third tertile > 2.83 mIU/L), and periodontal condition was assessed using the Community Periodontal Index. Of the total of 5468 participants, 1423 had periodontitis (26%). A significant difference in the weighted prevalence of periodontitis according to TSH tertiles was observed, with the highest prevalence in the first tertile (26.5%) and the lowest prevalence in the third tertile (20.9%, p = 0.003). Subjects in the first TSH tertile had higher odds for periodontitis than those in the third tertile (OR 1.36, 95% CI 1.10-1.68; p for trend = 0.005) after adjusting for covariates. This association was consistent across subgroups and within sensitivity analyses among subjects without specific factors affecting thyroid function or diseases reported to be related to periodontitis. The present study demonstrated that low TSH levels were associated with significantly higher odds for periodontitis.

Does thyroid dysfunction influence inflammatory mediators in experimental periodontitis?

Objective. The aim of the present study was to investigate the presence of inflammatory mediators in rats with only periodontitis and periodontitis in a setting of hyper- and hypo-thyroidism and to analyze the correlative linkages between inflammatory mediators and thyroid hormones. Methods. White male 12-14 weeks old inbred rats (n=48) weighing 180-200 g were employed in the experiment. They were randomly divided into the following groups: Group I - control group, Group II - group with a model of periodontitis, Group III - group with a periodontitis in a setting of hyperthyroidism, and Group IV - group with periodontitis in a setting of hypothyroidism. The presence of tumor-necrosis factor-α (TNF-α) and interleukins IL-1β and IL-10 in the periodontal homogenate supernatant was studied by a solid-phase enzyme-linked immunosorbent assay. Results. It was shown that experimental lipopolysaccharide (LPS)-induced periodontitis is accompanied by hyperproduction of pro-inflammatory cytokines (TNF-α, IL-1β) and reduction of anti-inflammatory cytokines (IL-10), whereas TNF-α underwent to maximum changes. Thyroid dysfunction exacerbates cytokine imbalance and severity of inflammation in experimental LPS-induced periodontitis, especially pronounced at hyperthyroidism, as evidenced by the predominance of TNF-α and IL-1β levels in the periodontal homogenate supernatant by 38.5% (р<0.01) and 75.6% (p<0.001), respectively, hyperthyroid over the euthyroid, and by 20.1% (p<0.05) and 24.1% (p<0.05), respectively, over the hypothyroid rats. Conclusions. Thyroid dysfunction, especially hyperthyroidism, may play an important role in the pro-inflammatory response in periodontitis. Hyperproduction of inflammatory mediators in thyroid dysfunction can induce a noticeable damage in the whole apparatus of the periodontium, thereby causing progression of periodontitis.

Influence of photodynamic therapy on the periodontitis-induced bone resorption in rat

This study aimed to evaluate the effects of toluidine blue-mediated photodynamic therapy (TB-PDT) on the periodontitis-induced bone resorption in periodontitis in rats. Periodontal disease was induced by cotton ligature around the right second maxillary molar in 64 rats. After 4 weeks, the rats were randomly divided into four groups: sterile saline solution (control group); laser therapy (laser group); TB (100 μg/mL); TB plus laser (0.15 W/cm2) irradiation every other day for 240 s (PDT group). All rats were euthanized at 15 days postoperatively. Eight gingival tissue samples were collected from each group. The expressions of receptor activator of nuclear factor kappa-Β ligand (RANKL) and osteoprotegerin (OPG) in gingival tissue samples were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The maxillae from the rest of the rats were taken for histological examination. In the PDT group, the analysis revealed less bone loss than in the control treatment (P < 0.05). No significant difference was found among the control group, TB group, and laser group (P > 0.05). Significantly higher and lower expressions of RANKL and OPG were revealed in the PDT group than that in control group, respectively (P < 0.01). When compared with the control group, the expression of RANKL was significantly reduced by 40.0% in periodontitis in rats treated with TB-PDT for 15 days (P < 0.01). The expression of OPG was increased in the PDT group with TB-PDT for 15 days, when compared with the control group (P < 0.05). TB-PDT treatment significantly reverses the abnormal expression of RANKL and OPG in periodontitis in rats.

ENDOCRINE REGULATION OF ERYTHROID LINEAGE OF HEMATOPOIESIS IN CHILDREN LIVING UNDER A LOW-DOSE RADIATION EXPOSURE AFTER THE CHORNOBYL NPP ACCIDENT

OBJECTIVE

Elucidation of relationship between the levels of thyroid-stimulating hormone (TSH), free serum thyroxine, serum and urine cortisol and parameters of erythroid lineage of hematopoiesis to estimate the thyroid functionin children of prepubertal, pubertal, and postpubertal age permanently residing under a low-dose radiation exposureto determine the premorbid state of thyroid function.

MATERIALS AND METHODS

Children aged 3 to 18 years old (n = 203) living in the most intensively radionuclide-contaminated regions of Kyiv, Zhytomyr and Chornihiv oblasts of Ukraine after the Chornobyl NPP accident wereenrolled. Complaints of ossalgia, arthralgia, fatigue, bone fractures in the history, bone dysembryogenetic stigmata,hypermobility syndrome degree, and types of somatic diseases were taken into account. Peripheral blood countparameters, biochemical indices of blood serum were studied, namely the levels of total protein, cholesterol, creatinine and alkaline phosphatase activity. Levels of the free thyroxine, pituitary TSH, serum and daily urine cortisol, anddoses of radiation exposure were determined.

RESULTS

The radiation dose values in children ranged from (0.35 ± 0.09) mSv to (0.54 ± 0.12) mSv. There was nodifference between the parameters of erythroid lineage of hematopoiesis depending on radiation dose. At the levels of serum TSH up to 1.0 μIU/ml no correlation was found with cortisol levels; at TSH levels of 1.0-3.0 μIU/ml thecorrelation coefficient was r = 0.31; at TSH levels higher than 3.0 μIU/ml the correlation coefficient was r = 0.61probably indicating a compensatory role of adrenal cortex in children at risk of thyroid disease development. In children with joint hypermobility grade II there was a higher incidence of dentofacial anomalies (χ2 = 6.9), deformitiesof lower extremities (χ2 = 6.9), and dental caries (χ2 = 4.3) (p < 0.05). There was a direct correlation between theserum TSH level (over 3 μIU/ml) and micrognathia (brachygnathia) (r = 0.62) indicating the impact of thyroid disease on dentofacial development. The TSH at a level of upper limit of the reference range values may contribute toa decreased RBC count in peripheral blood, increased average volume and hemoglobin content in erythrocyte beingassociated with the initial manifestations of thyroid dysfunction.

CONCLUSIONS

Abnormal endocrine regulation of hematopoiesis affects the connective tissue, stromal microenvironment of bone marrow, and accordingly the erythroid branch of hematopoiesis in children, which may be relevant inthe development and course of oncohematological diseases.