Correlation between clinical parameters characterising peri-implant and periodontal health: a practice-based research in Spain in a series of patients with implants installed 4-5 years ago.

OBJECTIVES: To explore peri-implant health (and relation with periodontal status) 4-5 years after implant insertion. STUDY DESIGN: A practice-based dental research network multicentre study was performed in 11 Spanish centres. The first patient/month with implant insertion in 2004 was considered. Per patient four teeth (one per quadrant) showing the highest bone loss in the 2004 panoramic X-ray were selected for periodontal status assessment. Bone losses in implants were calculated as the differences between 2004 and 2009 bone levels in radiographs. RESULTS: A total of 117 patients were included. Of the 408 teeth considered, 73 (17.9%) were lost in 2009 (losing risk: >50% for bone losses ≥7 mm). A total of 295 implants were reviewed. Eight of 117 (6.8%) patients had lost implants (13 of 295 implants installed; 4.4%). Implant loss rate (quadrant status) was 1.4% (edentulous), 3.6% (preserved teeth), and 11.1% (lost teeth) (p=0.037). The percentage of implant loss significantly (p<0.001) increased when the medial/distal bone loss was ≥3 mm. The highest (p≤0.001) pocket depths were found in teeth with ≥5 mm and implants with ≥3 mm bone losses, with similar mean values (≥4 mm), associated with higher rates of plaque index and bleeding by probing. CONCLUSIONS: The significant bi-directional relation between plaque and bone loss, and between each of these two parameters/signs and pocket depths or bleeding (both in teeth and implants, and between them) together with the higher percentage of implants lost when the bone loss of the associated teeth was ≥3 mm suggest that the patient's periodontal status is a critical issue in predicting implant health/lesion.

Effect of oral bacteria on the mechanical behavior of titanium dental implants.

PURPOSE: This study sought to determine whether the mechanical properties of titanium dental implants changed after exposure to bacteria. MATERIALS AND METHODS: Two strains of bacteria (Streptococcus sanguinis and Lactobacillus salivarius) were used in the study. The adhesive properties of the two strains were investigated as follows. Titanium implants were placed in bacteria broth, seeded with the two bacteria strains, and left in the broth for 1 or 3 months. Another group of titanium implants was immersed in artificial saliva at 37°C for 3 months. Ten implants in each group were tested in 37°C artificial saliva to evaluate their mechanical flexural strength and fatigue life. RESULTS: The bacterial cultures grew quickly on titanium surfaces. After 1 month of bacteria culture in vitro, the bacteria had produced corrosion pits on the titanium surfaces. After 3 months of bacterial culture, a 7% decrease in the flexural strength of the implant samples and a decrease of 15% in the number of cycles to failure by fatigue were seen versus implants not exposed to bacteria. CONCLUSIONS: These results demonstrate that, in physiologic conditions in vitro, bacteria have the capacity to produce a pitting corrosion phenomenon on exposed titanium surfaces, leading to a significant deterioration in the mechanical properties of the implant. It is therefore logical to conclude that bacteria may produce corrosion that reduces the useful life of dental implants.

A propósito del termociclado. Breve exposición de los principios físicos en los que se basa / No disponible

En la investigación de materiales odontológicos con frecuencia se utilizan ensayos de Termociclado (TC) para discernir el efecto que producen los cambios de temperatura, que estos materiales soportan en el entorno oral, sobre su integridad. Los hallazgos que en la literatura se atribuyen a estas fluctuaciones térmicas son contradictorios. Objetivos: El objetivo de este artículo es examinar los principios físicos en que se basa y la metodología usada, para después plantearla hipótesis de su validez tal como hoy en día lo utilizamos y apuntarla necesidad de una investigación bien diseñada que nos permita su utilización con garantías de credibilidad. Conclusiones: Algunas de las causas que explicarían que los resultados de los ensayos de TC sean tan contradictorios serían la falta de protocolarización y estandarización de que adolecen, la ausencia de controles negativos, la naturaleza del líquido del baño y el solapamiento de los efectos de la inmersión y el tiempo total de esta (AU)

In the odonthological materials investigation, thermocicle tests are often used to find out the effect produced by the temperature changes wich these materials bear upon their integrity within the oral environment. The findings on literature related to these thermical fluctuations are contradictory (AU)