Status of retained deciduous second molars in subjects with agenesis of second premolars in relation to age.

AIM: To evaluate the presence and status of retained DM2 without permanent successors in relation to age. BACKGROUND: Preservation of retained deciduous second molars (DM2) can be applied to treat congenital absence of second premolars (PM2). However, the consequences of caries and progressing root resorption or infraocclusion may affect their survival. METHODS: Panoramic radiographs of individuals >10 years of age with agenesis of at least one PM2 were evaluated and divided into three groups according to age. The presence and location of retained DM2, caries/restorations, infraocclusion and root resorption were investigated. RESULTS: A total of 131 subjects with PM2 agenesis were included (mean age: 13 years 11 months). The majority were missing one or two PM2. In total, 174 retained DM2 were present (33%), and their incidence was higher in the younger age groups. Caries/restorations were found in 88 (50.6%) and infraocclusion in 21 (12%) retained DM2. The roots were resorbed mostly for ½ of the root length (35%). CONCLUSION: Long-term prognosis of retained DM2 without permanent successors seems uncertain, especially within the younger age group. In individuals older than 17 years, the prognosis for a healthy DM2 is favorable, if no distinct infraocclusion or extensive root resorption is present.

Evaluation of a relationship between malocclusion and idiopathic scoliosis in children and adolescents.

PURPOSE: Idiopathic scoliosis is a developmental deformation of the vertebral column of an unknown aetiology. Its clinical symptoms and hypothetical causative factors may affect the stomatognathic system. The aim of this study was to analyse the relationships between the prevalence and type of malocclusions, and the presence of idiopathic scoliosis, its location and severity. METHODS: This was a prospective longitudinal study. The study group consisted of 80 patients with idiopathic scoliosis and the control group of 61 healthy individuals. Standard standing long-cassette radiographs were taken of all of the patients in the idiopathic scoliosis group in order to confirm diagnosis, to determine localization and the Cobb angle of the curve. Both groups underwent standard clinical dental examination. RESULTS: The most commonly observed types included right main thoracic (R-MT) and thoracolumbar or left lumbar scoliosis (Cobb angle 11° to 125°). In the idiopathic scoliosis group, prevalence of malocclusions was greater than in the control group (95% versus 82%). In the idiopathic scoliosis group more than one type of malocclusion was observed with a higher incidence than that in the control group (63.8% versus 37.7%; p = 0.002). A correlation between the left proximal thoracic (L-PT) curve with anterior partial open bite was demonstrated (p = 0.323), between thoracic dextroscoliosis main thoracic with lateral partial cross bite (p = 0.230) and a correlation between scoliosis severity and malocclusion in the event of L-PT and anterior partial open bite (p = 0.330) and R-MT and scissors bite (p = 0.248). CONCLUSION: The incidence of malocclusions is greater in children with idiopathic scoliosis than in their healthy peers. LEVEL OF EVIDENCE: III.

GREM2 nucleotide variants and the risk of tooth agenesis.

OBJECTIVE: The etiology of tooth agenesis (TA) is multifactorial and still not fully understood. The aim of the study was to test whether variants of GREM2, encoding a bone morphogenetic protein (BMP) antagonist, are associated with the risk of this common dental anomaly in a Polish population. SUBJECTS AND METHODS: Direct sequencing of the GREM2 coding sequence including exon/intron boundaries was performed in 95 patients with both hypodontia and oligodontia. All identified GREM2 variants were then further tested in an independent group of patients (n = 163) and controls (n = 184). RESULTS: The previously described, functional GREM2 mutation (c.226C > G, p.Gln76Glu) was identified in two patients with hypodontia and associated dental anomalies, including taurodontism and microdontia. This mutation generating an allele with increased inhibitory activity was not detected in the control group. The second identified GREM2 variant, c.-1-21C > T (rs11806449), was not associated with the risk TA. The polymorphism allele frequency in both patients and controls was 0.21 (OR = 1.0, 95%CI: 0.76-1.46). The rs11806449 did not correlate either with the overall TA phenotype or hypodontia/oligodontia phenotypes. CONCLUSION: Our study confirmed that GREM2 is a candidate gene for tooth agenesis, which mutations can explain, however, only a small fraction of the genetic contribution to the pathogenesis of this anomaly.

Common variants in DLG1 locus are associated with non-syndromic cleft lip with or without cleft palate.

Non-syndromic cleft lip with or without cleft palate (nsCL/P) is a common craniofacial anomaly with a complex and heterogeneous aetiology. Knowledge regarding specific genetic factors underlying this birth defect is still not well understood. Therefore, we conducted an independent replication analysis for the top-associated variants located within the DLG1 locus at chromosome 3q29, which was identified as a novel cleft-susceptibility locus in our genome-wide association study (GWAS). Mega-analysis of the pooled individual data from the GWAS and replication study confirmed that common DLG1 variants are associated with the risk of nsCL/P. Two single nucleotide polymorphisms (SNPs), rs338217 and rs7649443, were statistically significant even at the genome-wide level (Ptrend = 9.70E-10 and Ptrend = 8.96E-09, respectively). Three other SNPs, rs9826379, rs6805920 and rs6583202, reached a suggestive genome-wide significance threshold (Ptrend < 1.00E-05). The location of the strongest individual SNP in the intronic sequence of the gene encoding DLG1 antisense RNA suggests that the true causal variant implicated in the risk of nsCL/P may affect the DLG1 gene expression level rather than structure of the encoded protein. In conclusion, we identified a novel cleft-susceptibility locus at chromosome 3q29 with a DLG1 as a novel candidate gene for this common craniofacial anomaly.

Nucleotide variants of genes encoding components of the Wnt signalling pathway and the risk of non-syndromic tooth agenesis.

Tooth agenesis is one of the most common dental anomalies, with a complex and not yet fully elucidated aetiology. Given the crucial role of the Wnt signalling pathway during tooth development, the purpose of this study was to determine whether nucleotide variants of genes encoding components of this signalling pathway might be associated with hypodontia and oligodontia in the Polish population. A set of 34 single nucleotide polymorphism (SNPs) in 13 WNT and WNT-related genes were analyzed in a group of 157 patients with tooth agenesis and a properly matched control group (n = 430). In addition, direct sequencing was performed to detect mutations in the MSX1, PAX9 and WNT10A genes. Both single-marker and haplotype analyses showed highly significant association between SNPs in the WNT10A gene and the risk for tooth agenesis. Moreover, nine pathogenic mutations within the coding region of the WNT10A gene were identified in 26 out of 42 (62%) tested patients. One novel heterozygous mutation was identified in the PAX9 gene. Borderline association with the risk of non-syndromic tooth agenesis was also observed for the APC, CTNNB1, DVL2 and WNT11 polymorphisms. In conclusion, nucleotide variants of genes encoding important components of the Wnt signalling pathway might influence the risk of tooth agenesis.

Clinical use of allogeneic bone granulates to reconstruct maxillary and mandibular alveolar processes.

INTRODUCTION: Lack of adequate mass of a patient's own bone is still a clinical problem in dental implantology; it precludes dental embedment. Surgical widening of an atrophied alveolar process with the use of an allogeneic bone granulate to fill the bone defect constitutes a first-line method to prepare for implant-prosthetic treatment. Transplantation of allogeneic material allows reconstruction of optimal height, thickness, and width of the alveolar process facilitating a procedure with a good long-term outcome. The study assessed outcomes following augmentation of atrophied alveolar processes before intraosseous implantation. MATERIALS AND METHODS: Filling bone defects in the maxilla and mandible as an introductory measure for implant-prosthetic treatment was performed in 59 patients (24 females and 35 males of age range 22-65 years). Bone granulate was used for maxillary sinus floor elevation (n=29), augmentation of the postextraction alveoli (n=12), and filling of defects in the outer table of the compact bone formed following inflammatory conditions (n=18). The bone grafts were covered with plasma-rich fibrin (PRF) obtained from the patient's blood to accelerate the formation of synostoses and prevent epithelial penetration between the patients' own bone and the bone graft. RESULTS: In all of the patients normal union was observed, as confirmed by radiological images as well as intraprocedural assessment. Sufficient height and width as well as thickness of the alveolar process was obtained, which allowed embedment. CONCLUSIONS: Allogeneic bone granulate constitutes a good material to reconstruct maxillary and mandibular alveolar processes in out-patient care.

[The use of a computer to measure linear and angular variables for an assessment of symmetry of the base of the skull]. / Zastosowanie komputera do liniowych i katowych pomiarów symetrii podstawy czaszki.

The use of a computer is described to make linear and angular measurements of the base of the skull. A group of 19 adult skulls from mediaeval Poland were chosen for this study. The cephalometric analysis defined 11 linear and 9 angular morphological variables. An assessment of method error due to point location by the cursor was made by duplicate determination, and an assessment of symmetry was carried out by comparing angular values derived from basion (ba) for right and left sides of the maxillary dental arch, zygomatic arch and cranial base. The results demonstrate that skull measurements could be recorded with a small method error of 0.2 mm for linear, and 0.2 degrees for angular recordings. Mean values for the 21 variables in the sample were recorded and statistically tested for point placement accuracy using measures of skewness and kurtosis to detect gross distribution errors.

[Methods of treatment of preschool children used in the orthodontics department, Institute of Stomatology, Medical Academy in Warsaw]. / Metody leczenia dzieci w wieku przedszkolnym stosowane w zakladzie ortodoncji is am w Warszawie.

The reported analysis was based on 288 clinical cards of patients aged 2 to 6 years, admitted for treatment in the years 1980-1985. The greatest group was that of children aged 3 years (28%), followed by those aged 6 years (25%). Abnormalities from the group of distocclusion prevailed (28%), followed by teeth abnormalities (26%), and cross-bite (16%). In 165 cases functional apparatus was used initially, in 66 cases Schwarz or Adams plates, in 31 cases dental prostheses, and in 22 cases chin sling. Four cases were observed after removal of malocclusion cause. Besides treatment with removable devices myotherapy and spatula exercises were used.

[Shape of dental arches and their dimensions in children without malocclusion aged 3 years]. / Ksztalt luków zebowych i ich wymiary u dzieci 3-letnich bez wad zgryzu.

The dental arches were analysed in 3-year-old children without malocclusion evaluating the shape of arches, measuring their with, length and depth. The index of the dental arch and the palatal index were calculated. In children aged 3 years the shape of the upper dental arch was in most cases similar to a semi-ellipse and that of the lower arch approached parabole. This suggests that the semicircular shape of dental arches is not characteristic of this period of occlusion development.

[Diastemata in 3-year-old children without malocclusion]. / Szpary miedzyzebowe u dzieci 3-letnich bez wady zgryzu.

In children aged 3 years without malocclusion the dental arches were studied for the occurrence, position and size of diastemata (interdental clefts). In the studied children most arches had diastemata (in 95% of cases in the upper arch and in 80% in the lower arch). It is concluded that the behaviour of the contact points between teeth is not a characteristic feature of the teeth of children aged 3 years. It seems that the presence of "closed" dental arches--without diastemata, and "open" with diastemata, confirms the presence of two types of dental arches of milk teeth.