Histologic, histomorphometric, and radiographic monitoring of bone healing around in-office-sterilized orthodontic mini-implants with or without immediate load: study in rabbit tibiae.

PURPOSE: The objective of this study was to describe bone healing around self-drilling orthodontic mini-implants (MIs), sterilized in an office with an autoclave, with or without immediate orthodontic loading. MATERIALS AND METHODS: One hundred forty-four self-drilling MIs (TOMAS, Dentaurum) were inserted into the tibiae of 18 white rabbits, with full-thickness flaps elevated under general anesthesia. An immediate load (50 cN) was applied to 50% of the MIs. Two rabbits were sacrificed soon after the surgery and served as a control group. Four rabbits each were sacrificed at 15, 21, 30, or 60 days after the surgeries. Digital radiographs were obtained to measure the cortical bone thickness (CBT) around and between the implants. Sections were obtained and stained for histologic and histomorphometric analysis. Bone quantity (BQ), bone-to-implant contact (BIC), and CBT were evaluated statistically. RESULTS: At day 0, fractures were visible in the cortical area around the MIs. At days 15 and 21, intense proliferation of woven bone followed by formation of lamellar bone was seen. After 30 days, primary bone was visible, with less proliferation activity. At day 60, primary bone in the process of remodeling into secondary bone was apparent. BQ was better with loading after 15 days and increased throughout the healing period in the loaded and unloaded groups. Loading did not influence the BIC values, which increased with healing time for loaded and unloaded implants. CBT increased in all regions, and CBT was greater around the MIs than between them except for unloaded MIs in the 15-day group. CONCLUSION: An immediate, light orthodontic load did not affect the bone healing process around orthodontic MIs. Osseointegration and CBT increased and were time-related.

A comparative clinical study of the failure rate of orthodontic brackets bonded with two adhesive systems: conventional and self-etching primer (SEP).

OBJECTIVE: This study compared the clinical performance of orthodontic brackets bonded with Transbond adhesive paste after two primer systems: a two-stage conventional system (acid etching + Transbond XT adhesive primer) and a single-stage self-etching primer (SEP) (Transbond Plus). METHODS: The sample comprised 480 metal brackets bonded to the teeth of 24 consecutive patients treated for 36 to 48 months. A split-mouth design was used for bonding, and both systems were used in each patient. Bracket failure rates for each system were analyzed; and failure causes as reported by the patients and the quadrant of teeth for which brackets failed were recorded. RESULTS: The conventional system group had a failure rate of 5.41%, whereas the rate for SEP was 4.58%. In this group, there were 5 failures (38.4%) in the right maxillary quadrant, 2 (15.4%) in the left maxillary quadrant, 4 (30.8%) in the right mandibular quadrant, and 2 (15.4%) in the left mandibular quadrant. In the SEP group, there were 4 (36.4%) failures in the right maxillary quadrant, 1 (9%) in the left maxillary quadrant, 3 (27.3%) in the right mandibular quadrant, and 3 (27.3%) in the left mandibular quadrant. Results of descriptive statistical analysis and odds ratio did not show any significant differences between rates (p = 0.67). CONCLUSIONS: The clinical efficiency of SEP was similar to that of the conventional system.

A comparative clinical study of the failure rate of orthodontic brackets bonded with two adhesive systems: conventional and self-etching primer (SEP)

OBJECTIVE: This study compared the clinical performance of orthodontic brackets bonded with Transbond adhesive paste after two priming systems: a two-stage conventional system (acid etching + Transbond XT adhesive primer) and a singlestage self-etching primer (SEP) (Transbond Plus). METHODS: The sample comprised 480 metal brackets bonded to the teeth of 24 consecutive patients treated for 36 to 48 months. A split-mouth design was used for bonding, and both systems were used in each patient. Bracket failure rates for each system were analyzed; and failure causes as reported by the patients and the quadrant of teeth for which brackets failed were recorded. RESULTS: The conventional system group had a failure rate of 5.41%, whereas the rate for SEP was 4.58%. In this group, there were 5 failures (38.4%) in the right maxillary quadrant, 2 (15.4%) in the left maxillary quadrant, 4 (30.8%) in the right mandibular quadrant, and 2 (15.4%) in the left mandibular quadrant. In the SEP group, there were 4 (36.4%) failures in the right maxillary quadrant, 1 (9%) in the left maxillary quadrant, 3 (27.3%) in the right mandibular quadrant, and 3 (27.3%) in the left mandibular quadrant. Results of descriptive statistical analysis and odds ratio did not show any significant differences between rates (p = 0.67). CONCLUSION: The clinical efficiency of SEP was similar to that of the conventional system.

OBJETIVO: o objetivo do presente estudo foi comparar o desempenho clínico da colagem de braquetes ortodônticos com resina Transbond (3M Unitek) associada a dois sistemas adesivos: convencional em duas etapas (ataque ácido + Transbond XT adhesive Primer) e Self-Etching Primer (SEP), em etapa única (Transbond Plus). MÉTODOS: a amostra foi constituída de 480 braquetes metálicos (Victory, 3M Unitek), colados em 24 pacientes, que foram tratados durante um período de 36 a 48 meses. A colagem foi feita por meio do sistema split-mouth, utilizando os dois sistemas de colagem em cada paciente. Foi analisada a taxa de queda dos braquetes para cada sistema de colagem, descrita a causa da queda conforme relato do paciente e a posição dos dentes nas arcadas. RESULTADOS: o sistema adesivo convencional apresentou taxa de queda de 5,41%, enquanto a do SEP foi de 4,58%. O sistema convencional apresentou 5 quedas (38,4%) no quadrante superior direito, 2 (15,4%) no quadrante superior esquerdo, 4 (30,8%) no quadrante inferior direito e 2 (15,4%) no quadrante inferior esquerdo. O SEP apresentou 4 quedas (36,4%) no quadrante superior direito, 1 (9%) no quadrante superior esquerdo, 3 (27,3%) no quadrante inferior direito e 3 (27,3%) no quadrante inferior esquerdo. Por meio da análise estatística descritiva e do teste Odds Ratio, constatou-se que não houve diferença significativa entre essas taxas (p = 0,67). CONCLUSÃO: com base nesses resultados, pode-se concluir que o sistema adesivo SEP apresentou eficácia clínica semelhante à do sistema adesivo convencional.

Monitoramento histológico, histomorfométrico e radiográfico da cicatrização óssea ao redor de mini-parafusos ortodônticos autoperfurantes, submetidos ou não à aplicação de carga imediata, em tíbias de coelhos / Histological, histomorphometric and radiographic monitoring of bone healing around self-drilling orthodontic mini-screws, subjected or not to immediate load in rabbit tibiae

Mini-implantes ortodônticos são acessórios de ancoragem esquelética. O objetivo deste estudo foi descrever a cicatrização óssea inicial ao redor dos mini-implantes, esterilizados pelos pesquisadores, submetidos ou não à aplicação de carga imediata. Foram inseridos 144 mini-implantes autoperfurantes (TOMAS®, Dentaurum, Germany) nas tíbias de dezoito coelhos brancos. Carga imediata (50 cN) foi aplicada sobre 50% dos mini-implantes. Quatro coelhos foram sacrificados em cada tempo pós-cirúrgico: dias 15, 21, 30 e 60, e dois no dia 0, constituindo grupo controle. Radiografias digitais foram obtidas para mensuração da espessura da cortical óssea (ECO), contíguo aos mini-implantes e equidistante deles. Nas imagens digitais das lâminas histológicas, realizou-se análise histológica e histomorfométrica. Quantidade de osso (QO), contato osso-implante (BIC) e ECO foram analisados pelos testes t-pareado, ANOVA e coeficiente de correlação de Pearson. Aos 0 e 15 dias haviam áreas de fraturas da borda da cortical. Após 30 dias houve deposição de osso imaturo, que se apresentou maduro aos 60 dias. QO foi maior com carga aos 15 dias (p = 0,034); e aumentou ao longo da cicatrização, nos grupos com (p =0,004) e sem carga (p<0,001). Carga não afetou BIC; os valores aumentaram no decorrer do tempo, nos grupos com (p<0,001) e sem carga (p=0,001). ECO aumentou em todas as regiões (p<0,001). ECO próximo aos miniimplantes foi maior que no ponto médio, exceto aos 15 dias sem carga (p = 0.077). Concluiu-se que carga imediata leve não comprometeu a cicatrização óssea ao redor dos mini-implantes. Ósseointegração e o aumento da espessura da cortical óssea foram tempo-dependentes.

Mini-implants are attachments for orthodontic anchorage. This study aimed to describe the initial bone healing around mini-implants sterilized by the researchers, submitted or not to application of immediate loading. Were inserted 144 self-drilling mini-implants(TOMAS®, Dentaurum, Germany) in the tibia of eighteen white rabbits. Immediate loading (50 cN) was applied to 50% of mini-implants. The animals were sacrificed at each time post-surgery: day 15, 21, 30 and 60, and two on day 0, being the control group. Digital radiographs were obtained to measure the thickness of cortical bone (ECO), adjacent to mini-implants and equidistant from them. In digital pictures from histological slides histology and histomorphometry was analyzed. Amount of bone (QO), bone-implant contact (BIC) and ECO were analyzed by paired t-test, ANOVA and coefficient of Pearson correlation. At 0 and 15 days had shear areas. After 30 days there was deposition of immature bone, which appeared mature at 60 days. QO load was greater at 15 days (p = 0.034), and increased over healing in load (p = 0.004) and unloaded groups (p <0.001). Load affected BIC, the values increased over time in groups with load (p <0.001) and unloaded (p = 0.001). ECO increased in all regions (p <0.001). ECO near the mini-implants was greater than at midpoint, except for 15 days without load (p = 0,077). It was concluded that light immediate loading did not affect bone healing around the mini-implants. Osseointegration and increased cortical bone thickness were time-dependent.