BACKGROUND: The temporary anchorage devices (TAD) rely on mechanical retention to achieve their function. Following dental implants, the design has not been thoroughly studied. Most of the TADs available in the market are either conical or cylindrical homogenous designs. This study aims to evaluate whether a non-homogeneous design would be able to achieve better biomechanical properties than the current mini- screw designs available on the market. MATERIAL AND METHODS: This is a preliminary study comparing two different 1.5mm TAD designs, the Spider Screw® (Ortho Technology®), and one experimental TAD, the Novel TAD Design (NTD). The two TAD designs were generally described and evaluated following the ANSI/ADA Standard No. 178, then the core diameter / TAD diameter ratio was calculated at 0, 2, 4, and 6mm using the Mitutoyo PH-3500 projection machine in combination with QM-data 200. 10 TADs from each design were inserted in a 30 PCF laminated block from SAW Bone under a 12N axial load, using the Instron 5566A to measure the insertion torques and removal torques. Torque ratios were then calculated. Using the same Instron machine with TADs fully inserted in the artificial bone (2 per design per angle), pull-out tests were performed at angles of 0° / 30° / 60° / 90°. The TADs were loaded up to failure. One-way ANOVA and student's t-test were used for statistical analysis. RESULTS: The Spider Screw® is a conical, self-drilling, self-tapping design with the following general dimensions (d1: 1.5mm ; d2: 0.5mm; d3: 3.4mm; k1: 1mm; k2: 2mm; L1: 9.5mm; L2: 6.5mm; L3: 6.2mm), a 0.6mm pitch, 0.3mm thread depth, asymmetrical triangular threads. NTD, it is a cylindrical-conical, self-tapping design with the following general dimensions (d1: 1.5mm; d2: 0.85mm; d3: 2.5mm; k1: 1mm; k2: 2mm; L1: 9mm; L2: 6mm; L3: 6mm), a 0.5mm pitch, double threads in the first 2mm, a variable thread depth (0-2mm: 0.2mm ; 3-5mm: 0.35mm) and symmetrical rectangular threads. The core to width ratios for the Spider Screw® and NTD were respectively 1 ; 0.64 ; 0.61; 0.54 and 0.7; 0.53; 0.56 and 0.58. Mean insertion torque, removal torque and torque ratio for the Spider Screw and the NTD were respectively (12.78 N.cm / 11.32 N.cm, 0.90 ; 12.73 N.cm / 12.65 N.cm, 0.99 ) Mean pull-out forces at 0°/30°/60° and 90° for the Spider Screw® and the NTD were respectively 124.18 N / 108.59 N / 69.67 N / 84.75 N and 137.72 N / 109.7 N / 64.96 N / 66.78 N. There were no statistically significant differences found. CONCLUSIONS: After evaluating both of the TADs, it is clear that the designs are relatively different. The NTD showed to have a higher torque ratio, and therefore it could mean that the design would be clinically more effective. The NTD showed to perform as good or even slightly better than the Spider Screw® design, but a larger variety of TAD designs is needed to be able to confirm the conclusions of this study. / 2023-03-02T00:00:00Z

Widespread applications have made the use of mini-implants common throughout orthodontic treatment. The mini-implant provides an osseous anchor that is easily inserted, minimally invasive, and easily removed. The failure rate of mini-implants is estimated around 15%; this is high when juxtaposed with an endosseous implant. The majority of failures occur early; this results from a weakened bone-implant interface usually accompanied by soft tissue inflammation. This inflammation is exacerbated by poor oral hygiene and in areas of non-keratinized tissue, which provides an inadequate soft tissue barrier to bacterial challenges. Streptococcus mutans is involved in initial biofilm formation and has been implicated in endosseous peri-implantitis in the absence of periodontal disease. S. mutans is acidogenic, and has been shown to negatively affect the topography of titanium surfaces. Mini-implants are mainly comprised of titanium alloys due to their biocompatibility and mechanical strength. Literature suggests that enhancing the native TiO2 on titanium surfaces in the presence of UV light improves osseointegration, increases antibacterial effects, and increases soft tissue adhesion. The goal of this study was to enhance the TiO2 surface of mini-implants and evaluate the resultant anti-adherent, antibacterial, and topographical changes in the presence of S. mutans. Orthodontic mini-implants compromised of Ti6I4V, (Wrought Titanium-6 Aluminum 4 Vanadium ELI), were modified according to the parameters set by Unosson et al, 2015. These samples were then exposed to Streptococcus mutans and incubated at 37° C. Initial contact of viable bacteria was evaluated after 4 hours using resazurin dye that was measured on a fluorescence plate reader. Bacterial growth was evaluated at 4, 8, and 24 hours using a spectrometer to assess turbidity. Four samples were also plated to evaluate growth. SEM images were taken prior to and after treatment to assess topographical changes. ANOVA and pair-wise post-hoc tests were used to analyze the data. The amount of viable bacteria on modified mini-implant surfaces after 4 hours was significantly decreased when compared to controls (p< 0.004). Growth of S. Mutans on the modified surface after 24 hours was significantly less when assessed by spectroscopy (p<0.00083). Preliminary results show that modifying the surface of orthodontic mini-implants with H2O2 gel increases antibacterial properties against Streptococcus mutans, despite the lack of UV radiation. / Oral Biology

PROPOSIÇÃO Avaliou-se radiograficamente o grau de precisão de um guia radiográfico-cirúrgico na predição do posicionamento final de mini-implantes inseridos no septo inter-radicular e, sequencialmente, determinou-se um índice de risco para normatizar a indicação do procedimento de inserção dos mini-implantes. MATERIAL E MÉTODOS Um total de 53 mini-implantes foram inseridos no septo inter-radicular vestibular da região posterior da maxila e/ou mandíbula de 27 pacientes com idade média de 19,17 ± 9,06 anos (idade mínima de 12,72 anos e máxima de 56,37 anos). O Guia Radiográfico-Cirúrgico Graduado (GRCG) foi utilizado para inserir os mini-implantes no centro do septo de forma equidistante em relação às raízes dos dentes adjacentes. As distâncias entre o mini-implante e as raízes dos dentes adjacentes foram mensuradas nas 53 radiografias pós-cirúrgicas com intuito de avaliar a precisão do GRCG a partir do grau de centralização do mini-implante no septo. O grau de imprecisão do GRCG foi associado à largura do septo e ao diâmetro do mini-implante para compor a fórmula do índice de risco utilizada na avaliação do risco cirúrgico de inserção dos mini-implantes. RESULTADOS O grau de imprecisão do GRCG mostrou que, em média, os mini-implantes foram inseridos com um desvio de 0,13mm (±0,13) em relação ao centro do septo. O valor médio do índice de risco (IR) foi menor do que 1, significando um reduzido risco cirúrgico. CONCLUSÕES A ligação estabelecida entre os procedimentos radiográfico e cirúrgico proveu ao GRCG um reduzido grau de imprecisão de 0,13mm, e uma acurada predição do posicionamento final do mini-implante no septo inter-radicular, contribuindo para um reduzido risco cirúrgico (IR<1). / OBJECTIVE This study evaluated the radiographic-surgical guide accuracy to predict post-surgical mini-implant positioning in the interradicular septum. Additionally, a risk index to standardize surgical procedure indication for mini-implant insertion was determined. MATERIAL AND METHODS A total of fifty-three titanium mini-implants were placed in the buccal interradicular septum of the posterior maxillary and/or mandibular region of 27 patients with a mean age of 19.17 ± 9.06 years (ranging from 12.72 to 56.37 years). The Graduated Radiographic-Surgical Guide (GRSG) was used to insert mini-implants in the interradicular septum in a centralized and equidistant position regarding adjacent tooth roots. The fifty-three post-surgical radiographs were used to measure the distances between mini-implants and adjacent tooth roots to evaluate GRSG accuracy in obtaining mini-implant centralized position in the septum. The GRSG inaccuracy degree was related to the septum width and the mini-implant diameter to obtain risk index formula, which was used to predict surgical risks during mini-implants insertion. RESULTS The GRSG inaccuracy degree showed that, on average, the mini-implants were 0.13mm (±0.13) displaced regarding the centralized position initially intended. The risk index (RI) presented a mean value smaller than 1, indicating a reduced surgical risk. CONCLUSION The link established between radiographic and surgical procedures propitiated a small GRSG inaccuracy degree of 0.13mm, allowing an accurate prediction of the final mini-implant positioning in the interradicular septum, which contributed to a low surgical risk (RI<1).

PROPOSIÇÃO Avaliou-se radiograficamente o grau de precisão de um guia radiográfico-cirúrgico na predição do posicionamento final de mini-implantes inseridos no septo inter-radicular e, sequencialmente, determinou-se um índice de risco para normatizar a indicação do procedimento de inserção dos mini-implantes. MATERIAL E MÉTODOS Um total de 53 mini-implantes foram inseridos no septo inter-radicular vestibular da região posterior da maxila e/ou mandíbula de 27 pacientes com idade média de 19,17 ± 9,06 anos (idade mínima de 12,72 anos e máxima de 56,37 anos). O Guia Radiográfico-Cirúrgico Graduado (GRCG) foi utilizado para inserir os mini-implantes no centro do septo de forma equidistante em relação às raízes dos dentes adjacentes. As distâncias entre o mini-implante e as raízes dos dentes adjacentes foram mensuradas nas 53 radiografias pós-cirúrgicas com intuito de avaliar a precisão do GRCG a partir do grau de centralização do mini-implante no septo. O grau de imprecisão do GRCG foi associado à largura do septo e ao diâmetro do mini-implante para compor a fórmula do índice de risco utilizada na avaliação do risco cirúrgico de inserção dos mini-implantes. RESULTADOS O grau de imprecisão do GRCG mostrou que, em média, os mini-implantes foram inseridos com um desvio de 0,13mm (±0,13) em relação ao centro do septo. O valor médio do índice de risco (IR) foi menor do que 1, significando um reduzido risco cirúrgico. CONCLUSÕES A ligação estabelecida entre os procedimentos radiográfico e cirúrgico proveu ao GRCG um reduzido grau de imprecisão de 0,13mm, e uma acurada predição do posicionamento final do mini-implante no septo inter-radicular, contribuindo para um reduzido risco cirúrgico (IR<1). / OBJECTIVE This study evaluated the radiographic-surgical guide accuracy to predict post-surgical mini-implant positioning in the interradicular septum. Additionally, a risk index to standardize surgical procedure indication for mini-implant insertion was determined. MATERIAL AND METHODS A total of fifty-three titanium mini-implants were placed in the buccal interradicular septum of the posterior maxillary and/or mandibular region of 27 patients with a mean age of 19.17 ± 9.06 years (ranging from 12.72 to 56.37 years). The Graduated Radiographic-Surgical Guide (GRSG) was used to insert mini-implants in the interradicular septum in a centralized and equidistant position regarding adjacent tooth roots. The fifty-three post-surgical radiographs were used to measure the distances between mini-implants and adjacent tooth roots to evaluate GRSG accuracy in obtaining mini-implant centralized position in the septum. The GRSG inaccuracy degree was related to the septum width and the mini-implant diameter to obtain risk index formula, which was used to predict surgical risks during mini-implants insertion. RESULTS The GRSG inaccuracy degree showed that, on average, the mini-implants were 0.13mm (±0.13) displaced regarding the centralized position initially intended. The risk index (RI) presented a mean value smaller than 1, indicating a reduced surgical risk. CONCLUSION The link established between radiographic and surgical procedures propitiated a small GRSG inaccuracy degree of 0.13mm, allowing an accurate prediction of the final mini-implant positioning in the interradicular septum, which contributed to a low surgical risk (RI<1).

O tratamento com mini-implantes tem sido utilizado para retenção de overdentures por possuir menor custo, menor desconforto pós-operatório e proporcionar adequada reabilitação da estética, função e fonação. Este ensaio clínico randomizado, com acompanhamento de 2 anos, foi realizado com o intuito de comparar a qualidade de vida associada à saúde bucal (QVSB), satisfação do paciente, bem como as taxas de sucesso de implantes e overdentures, retidas por implantes ou mini-implantes. Na fase inicial, a amostra foi composta de 120 indivíduos edêntulos que foram alocados aleatoriamente em três grupos de acordo com o tratamento recebido: (GI) quatro mini-implantes, (GII) dois mini-implantes, ou (GIII) dois implantes regulares. Durante o acompanhamento de 1 e 2 anos, a amostra foi reduzida para 106 e 96 participantes, respectivamente. A QVSB, mensurada pelo questionário OHIP-EDENT, e a satisfação (aferida por questões específicas respondidas em EVA 100mm) foram avaliadas antes da intervenção e após o período de acompanhamento. Outra variável utilizada para verificar a efetividade do tratamento foi a taxa de sucesso de implantes e overdentures, que foi obtida por meio de parâmetros clínicos e sobrevivência dos implantes. Os grupos foram comparados por meio de Equações de Estimação Generalizadas (EEG) (&alpha;=0,05), e teste post hoc de Bonferroni. Após análise da diferença entre as médias dos escores obtidos para QVSB e satisfação, verificou-se diferença significante, entre grupos tratados e tempo, apenas para a segunda variável. Assim, a modalidade de tratamento não interferiu na qualidade de vida dos participantes após 1 e 2 anos. Para este período, a satisfação foi maior para o grupo I (GI: 1ano - &Delta;61 mm, 2 anos - &Delta;55 mm), embora o grupo II (GII: 1 ano - &Delta;52 mm, 2 anos - &Delta; 45 mm) apresentasse valores intermediários e o grupo 3 (GIII: 1 ano 32 mm, 2 anos - 31 mm), valores aceitáveis dentro do tratamento. A taxa de sobrevivência dos implantes foi maior para o grupo de implantes regulares: GI (n=152): 88,8%; GII (n=84): 82,1% e GIII (n=80): 97,5%. Para os critérios de sucesso, os únicos parâmetros a apresentarem diferenças entre os grupos foram dor (maior frequência, GIII) e sangramento à sondagem (maior frequência, GI), apenas no 2º ano. Índice de placa, sangramento e profundidade de sondagem aumentaram com o tempo, sendo que GI e GII atingiram menor média. Conclui-se que o tratamento com overdenture, independente do tipo de implantes, teve impacto positivo na QVSB, enquanto a satisfação foi maior no grupo de quatro mini-implantes. Além disso, overdentures retidas por mini-implantes ou implantes regulares atingiram sucesso clínico em 2 anos. / Mandibular overdentures retained by mini implants have provide a good retention and lower cost, postoperative discomfort in rehabilitation of aesthetics, function and phonation. This study aimed to follow up a 2-year randomized clinical trial to compare the quality of life associated with oral health (QVSB), patient satisfaction, as well as the success rates of implants and overdentures after the installation Of mini-implants (two or four) or two conventional implants. In the initial phase, the sample consisted of 120 edentulous individuals were randomly allocated into three groups according to the treatment received: (GI) four mini-implants, (GII) two mini-implants, or (GIII) two regular implants. During follow-up of 1 and 2 years the sample was reduced to 106 and 96 participants, respectively. The QVSB, measured by the OHIP-EDENT questionnaire, and satisfaction (measured by specific questions answered in EVA 100mm) were evaluated before the intervention and after the follow-up period. Another variable used to verify the effectiveness of the treatment was the success rate of implants and overdentures, which was obtained through clinical parameters and implant survival. The groups were compared using Generalized Estimation Equations (EEG) (&alpha;= 0.05), and post hoc Bonferroni test. After analyzing the difference between the means of the scores obtained for QVSB and satisfaction, a significant difference was observed between treated groups and time, only for the second variable. Thus, the treatment modality did not interfere in the participants\' quality of life after 1 and 2 years. For this period, the satisfaction was highest for the groups of four mini-implants (GI: 1 year - &Delta;61 mm, 2 years - &Delta; 55 mm), although the two mini-implants (GII: 1 year - &Delta;52 mm, 2 years - &Delta; 45 mm) presented intermediate values and the groups of regular implants (GIII: 1 year - 32 mm, 2 years - 31 mm) had acceptable values within the treatment. The survival rate of the implants was higher for the group of conventional implants: GI (n = 152): 88.8%; GII (n = 84): 82.1% and GIII (n = 80): 97.5%. For the success criteria, the only parameters to present differences between the groups in the second year were pain and bleeding. The first occurred more frequently in the GIII while the second occurred in the GI. Peri-implant parameters (IP, SS, PS) increased with time and groups of mini-implants reached lower mean. It was concluded that overdenture treatment, regardless of the type of implant, has a positive impact on QVSB, while satisfaction was higher in the group of four mini-implants. In addition, overdentures retained by mini-implants or regular implants have achieved clinical success in 2 years.

O tratamento com mini-implantes tem sido utilizado para retenção de overdentures por possuir menor custo, menor desconforto pós-operatório e proporcionar adequada reabilitação da estética, função e fonação. Este ensaio clínico randomizado, com acompanhamento de 2 anos, foi realizado com o intuito de comparar a qualidade de vida associada à saúde bucal (QVSB), satisfação do paciente, bem como as taxas de sucesso de implantes e overdentures, retidas por implantes ou mini-implantes. Na fase inicial, a amostra foi composta de 120 indivíduos edêntulos que foram alocados aleatoriamente em três grupos de acordo com o tratamento recebido: (GI) quatro mini-implantes, (GII) dois mini-implantes, ou (GIII) dois implantes regulares. Durante o acompanhamento de 1 e 2 anos, a amostra foi reduzida para 106 e 96 participantes, respectivamente. A QVSB, mensurada pelo questionário OHIP-EDENT, e a satisfação (aferida por questões específicas respondidas em EVA 100mm) foram avaliadas antes da intervenção e após o período de acompanhamento. Outra variável utilizada para verificar a efetividade do tratamento foi a taxa de sucesso de implantes e overdentures, que foi obtida por meio de parâmetros clínicos e sobrevivência dos implantes. Os grupos foram comparados por meio de Equações de Estimação Generalizadas (EEG) (&alpha;=0,05), e teste post hoc de Bonferroni. Após análise da diferença entre as médias dos escores obtidos para QVSB e satisfação, verificou-se diferença significante, entre grupos tratados e tempo, apenas para a segunda variável. Assim, a modalidade de tratamento não interferiu na qualidade de vida dos participantes após 1 e 2 anos. Para este período, a satisfação foi maior para o grupo I (GI: 1ano - &Delta;61 mm, 2 anos - &Delta;55 mm), embora o grupo II (GII: 1 ano - &Delta;52 mm, 2 anos - &Delta; 45 mm) apresentasse valores intermediários e o grupo 3 (GIII: 1 ano 32 mm, 2 anos - 31 mm), valores aceitáveis dentro do tratamento. A taxa de sobrevivência dos implantes foi maior para o grupo de implantes regulares: GI (n=152): 88,8%; GII (n=84): 82,1% e GIII (n=80): 97,5%. Para os critérios de sucesso, os únicos parâmetros a apresentarem diferenças entre os grupos foram dor (maior frequência, GIII) e sangramento à sondagem (maior frequência, GI), apenas no 2º ano. Índice de placa, sangramento e profundidade de sondagem aumentaram com o tempo, sendo que GI e GII atingiram menor média. Conclui-se que o tratamento com overdenture, independente do tipo de implantes, teve impacto positivo na QVSB, enquanto a satisfação foi maior no grupo de quatro mini-implantes. Além disso, overdentures retidas por mini-implantes ou implantes regulares atingiram sucesso clínico em 2 anos. / Mandibular overdentures retained by mini implants have provide a good retention and lower cost, postoperative discomfort in rehabilitation of aesthetics, function and phonation. This study aimed to follow up a 2-year randomized clinical trial to compare the quality of life associated with oral health (QVSB), patient satisfaction, as well as the success rates of implants and overdentures after the installation Of mini-implants (two or four) or two conventional implants. In the initial phase, the sample consisted of 120 edentulous individuals were randomly allocated into three groups according to the treatment received: (GI) four mini-implants, (GII) two mini-implants, or (GIII) two regular implants. During follow-up of 1 and 2 years the sample was reduced to 106 and 96 participants, respectively. The QVSB, measured by the OHIP-EDENT questionnaire, and satisfaction (measured by specific questions answered in EVA 100mm) were evaluated before the intervention and after the follow-up period. Another variable used to verify the effectiveness of the treatment was the success rate of implants and overdentures, which was obtained through clinical parameters and implant survival. The groups were compared using Generalized Estimation Equations (EEG) (&alpha;= 0.05), and post hoc Bonferroni test. After analyzing the difference between the means of the scores obtained for QVSB and satisfaction, a significant difference was observed between treated groups and time, only for the second variable. Thus, the treatment modality did not interfere in the participants\' quality of life after 1 and 2 years. For this period, the satisfaction was highest for the groups of four mini-implants (GI: 1 year - &Delta;61 mm, 2 years - &Delta; 55 mm), although the two mini-implants (GII: 1 year - &Delta;52 mm, 2 years - &Delta; 45 mm) presented intermediate values and the groups of regular implants (GIII: 1 year - 32 mm, 2 years - 31 mm) had acceptable values within the treatment. The survival rate of the implants was higher for the group of conventional implants: GI (n = 152): 88.8%; GII (n = 84): 82.1% and GIII (n = 80): 97.5%. For the success criteria, the only parameters to present differences between the groups in the second year were pain and bleeding. The first occurred more frequently in the GIII while the second occurred in the GI. Peri-implant parameters (IP, SS, PS) increased with time and groups of mini-implants reached lower mean. It was concluded that overdenture treatment, regardless of the type of implant, has a positive impact on QVSB, while satisfaction was higher in the group of four mini-implants. In addition, overdentures retained by mini-implants or regular implants have achieved clinical success in 2 years.