Association between craniofacial patterns and third molar agenesis in orthodontic patients

Purpose Third molar agenesis (TMA) is the most common craniofacial anomaly and has been associated with craniofacial patterns in different populations. Therefore, the aim of this retrospective cross-sectional study was to assess a possible association between craniofacial patterns and TMA in German orthodontic patients. Methods Patients undergoing orthodontic treatment with dental records including anamnesis, pretreatment lateral cephalograms and orthopantomograms were evaluated. Cephalometric analyses were conducted digitally and lines, angles and proportions were measured to investigate craniofacial morphology. Skeletal classes were determined by the individualised Wits appraisal and ANB angle. The TMA was identified with the help of orthopantomograms. Patients showing agenesis of at least one third molar were included in the TMA group. Statistical analysis was performed to assess the association between TMA and craniofacial patterns (α of p ≤ 0.05). Results A total of 148 patients were included, 40 (27.0%) presented at least one missing tooth (TMA group) and 108 (73.0%) showed full dentition (control group). Skeletal class determined by the individualised Wits appraisal revealed statistical significance between the TMA and control groups (p = 0.022), in which TMA patients were 11 times more likely to present with an individualised skeletal class III (odds ratio 11.3, 95% confidence interval 1.7–139.5). Skeletal cephalometric analysis revealed no statistical differences between TMA and control groups for any further angular, linear and proportional parameters. Conclusion Third molar agenesis was associated with skeletal class III determined by the individualised Wits appraisal

Polyethylene terephthalate clamps : optimization in endodontic and restorative practices

There is a growing search for innovations in dental materials and instruments and, therefore, an increase need to optimize the instruments used in the absolute isolation. The gold standard procedure contributes significantly to the quality of restorativ

Single Nucleotide Polymorphisms in COX2 Is Associated with Persistent Primary Tooth and Delayed Permanent Tooth Eruption

Persistent primary tooth (PPT) is a prevalent clinical condition that occurs when a primary tooth is over-retained beyond the established period of its normal exfoliation time, remaining in the oral cavity. Many factors could be involved in the risk of PPT; therefore, the aim of this study was to evaluate if single nucleotide polymorphisms (SNPs) in the COX2 gene are associated with PPT. Children undergoing orthodontic treatment were screened. Orthopantomographs were assessed to evaluate PPT according to the Nolla stage of its permanent successor. The primary tooth was considered retained when its successor permanent tooth was in Nolla stage 8 and below the alveolar crypt, Nolla stage 9, or Nolla stage 10. A saliva sample from each child was collected and used for DNA extraction. A real-time PCR of two SNPs, rs689466 (−1195 G/A) and rs5275 (+665 T/C), was performed. A chi-square test was used to compare the allele and genotype distribution. Haplotype analysis was also performed. A total of 100 children were included in the study. Fifty-one had at least one PPT, while 49 children were classified as a control. The number of teeth persistent in the oral cavity ranged from 1 to 8. The genotype distribution was associated with PPT in the co-dominant model (p = 0.006) for SNP rs5275. The individuals that carry two T alleles (TT) compared with the individuals that carry at least one C allele (C + TC) had an almost three times higher chance of presenting with PPT (p = 0.012; OR = 2.99, CI95% 1.28 to 6.95–recessive model). The haplotype C-A for the SNPs rs5275 and rs689466, respectively, was significantly associated (p = 0.042). In conclusion, single nucleotide polymorphisms in the gene encoding for COX2 are associated with persistent primary tooth and may delay permanent tooth eruption

Analysis of Primary Stability of Dental Implants Inserted in Different Substrates Using the Pullout Test and Insertion Torque

The aim of the study was to evaluate mechanical behavior of implants inserted in three substrates, by measuring the pullout strength and the relative stiffness. 32 implants (Master Porous-Conexao, cylindrical, external hexagon, and surface treatment) were divided into 4 groups (n=8): pig rib bone, polyurethane Synbone, polyurethane Nacional 40 PCF, and pinus wood. Implants were installed with the exact distance of 5 mm of another implant. The insertion torque (N·cm) was quantified using the digital Kratos torque meter and the pullout test (N) was performed by an axial traction force toward the long axis of the implant (2 min/mm) through mount implant devices attached to a piece adapted to a load cell of 200 Kg of a universal testing machine (Emic DL10000). Data of insertion torque and maximum pullout force were submitted to one-way ANOVA and Bonferroni tests (α=0.05). Polyurethane Nacional 40 PCF and pinus wood showed the highest values of insertion torque and pullout force, with significant statistical difference (P<0.05) with other groups. The analysis showed stiffness materials with the highest values for primary stability

Surface treatment of implants: primary stability

OBJECTIVE: The aim of this study was to analyze the primary stability of dental implants with and without surface treatment, by means of resonance frequency, using different materials as substitutes for human bone substrates for insertion.METHODS: Sixteen external hexagon, cylindrical Conexão(r)titanium implants were used, 11.5 mm long by 3.75 mm wide, as follows: 8 Master Porous (MP), with surface treatment and 8 Master Screw (MS) machined. The implant placement was performed on the following substrates: pork rib bone, wood, artificial bone polyurethane National(r) (40, 20, 15 PCF) and Synbone(r). Primary stability was assessed via resonance frequency using an Osstell Mentor(tm) device. Data were analyzed statistically using ANOVA and Tukey's test, with a significance level of 5%.RESULTS: It was found that although MP and MS have a higher value on all substrates, these were not statistically different between groups (p>0.05), except for polyurethane National(r)20 PCF. When inserted into the wood substrate and polyurethane National(r) 40 PCF, MP and MS had higher values&#8203;&#8203;. MP, when inserted into the pig bone, was also statistically equal to these interactions.CONCLUSION: Despite the continuous development of innovations in the characteristics of implant surfaces to assist with the performance of osseointegrated implants, and the fact that our study has found that the surface treatment had no impact on the primary stability checked using ressonance frequency, there is still very little scientific understanding of these effects

Effect of implant design and bone density in primary stability

Aim: To evaluate the influence of the format and surface treatment of implants, as well as the substrate used in primary stability. Methods: Thirty-two Conexão® implants were used: 8 conical (CC) (11.5 x 3.5 mm) and 24 cylindrical (11.5 x 3.75 mm) – 8 external hexagon implants without surface treatment (MS), 8 external hexagon implants with double Porous treatment (MP), 8 internal hexagon implants with Porous treatment (CA). They were inserted in Nacional® polyurethane in three densities (15, 20 and 40 PCF). The insertion torque (IT) (N.cm) was quantified using the digital Mackena® torque meter, and the pullout force (PF) (N) by means of axial traction force with a 200 kg load cell, performed in a Universal Test Machine (Emic® DL- 10000) and the Tesc 3.13 software. Data were analyzed statistically by ANOVA and Tukey’s test with a significance level of 5%. Results: Difference was observed between groups (p<0.05). Regarding the IT, MP and MS inserted to the substrate 40PCF showed higher values with statistically significant difference with all interactions implants x substrate; the 15 and 20PCF densities was not significant in all groups of implants. MP, MS, CC and CA did not differ significantly, even inserted in a lower density, where CC showed better IT compared with other densities. For PF, the best performance was the interaction implant CA x 40PCF substrate, showing a difference from the other implants inserted in all substrates. Conclusions: The higher bone density and cylindrical implants with surface treatment provides greater IT and PF

Effect of implant design and bone density in primary stability

evaluate the influence of the format and surface treatment of implants, as well as the substrate used in primary stability. Methods: Thirty-two Conexão® implants were used: 8 conical (CC) (11.5 x 3.5 mm) and 24 cylindrical (11.5 x 3.75 mm) 8 external hexagon implants without surface treatment (MS), 8 external hexagon implants with double Porous treatment (MP), 8 internal hexagon implants with Porous treatment (CA). They were inserted in Nacional® polyurethane in three densities (15, 20 and 40 PCF). The insertion torque (IT) (N.cm) was quantified using the digital Mackena® torque meter, and the pullout force (PF) (N) by means of axial traction force with a 200 kg load cell, performed in a Universal Test Machine (Emic® DL-10000) and the Tesc 3.13 software. Data were analyzed statistically by ANOVA and Tukeys test with a significance level of 5%. Results: Difference was observed between groups (p<0.05). Regarding the IT, MP and MS inserted to the substrate 40PCF showed higher values with statistically significant difference with all interactions implants x substrate; the 15 and 20PCF densities was not significant in all groups of implants. MP, MS, CC and CA did not differ significantly, even inserted in a lower density, where CC showed better IT compared with other densities. For PF, the best performance was the interaction implant CA x 40PCF substrate, showing a difference from the other implants inserted in all substrates. Conclusions: The higher bone density and cylindrical implants with surface treatment provides greater IT and PF