Accuracy of Implants Placed with Surgical Guides: Thermoplastic Versus 3D Printed.

This study was conducted to evaluate the accuracy of implants placed using two different guided implant surgery materials: thermoplastic versus three-dimensionally (3D) printed. A cone beam computed tomography (CBCT) scan previously obtained and selected for single-tooth implant replacement was converted into a Digital Imaging and Communications in Medicine (DICOM) file. All models were planned and exported for printing using BlueSkyBio Plan Software with the DICOM files. A total of 20 3D-printed mandibular quadrant jaws replicating the CBCT were printed by Right Choice Milling, as was the control model to accept the control implant. Previously, 10 thermoplastic and 10 3D-printed surgical guides had been made by the same lab technician at Right Choice Milling. One Nobel Biocare implant with a trilobe connection was placed per guide and replica jaw model pair. Implants were placed using the thermoplastic and 3D-printed surgical guides, representing the two test groups, following the Nobel Biocare guided surgical protocol. A total of 21 CBCT scans were then taken, one for the control implant and one for each test implant. The CBCT volume was converted to a DICOM file and transferred to Invivo5 software version 5.4 (Anatomage). The DICOM file of each test implant was superimposed over the DICOM file of the control. The deviation of the head of the implant, the deviation of the apex of the implant, and the angle of deviation were evaluated from measurements on the superimposition of the control and test implants. Mann-Whitney U test was used to test the null hypotheses at α = .05 and a confidence interval of 95%. Descriptive statistics were used for the average ± standard deviation. The implants placed with the thermoplastic surgical guides showed an average of 3.40 degrees of angular deviation compared to 2.36 degrees for implants placed with the 3D-printed surgical guides (P = .143). The implants placed with the thermoplastic surgical guides showed an average of 1.33 mm of deviation at the head of the implant compared to 0.51 mm for implants placed with the 3D-printed surgical guides (P < 0.001). The implants placed with the thermoplastic surgical guides showed an average of 1.6 mm of deviation at the apex of the implant compared to 0.76 mm for implants placed with the 3D-printed surgical guides (P < .001). There was no significant difference in the angular deviations of implants placed with thermoplastic surgical guides compared to those placed with the 3D-printed surgical guide. However, the locations of the implant head and implant apex were significantly more accurate for the implants placed with the 3D-printed surgical guides compared to those placed with the thermoplastic surgical guides.

Recovery of putative periodontal pathogens from curette sampling at different depths of periodontal lesions: an in vivo cross-sectional clinical study.

OBJECTIVE: The aim of this study was to evaluate the effect of the depth of curette sample collection from periodontal lesions on the recovery of putative periodontal pathogens using real-time polymerase chain reaction (PCR). METHODS: Twenty-two periodontal pockets 6 to 8 mm deep with bleeding on probing at a single-rooted tooth were sampled, yielding 66 separate samples. Curette samples were obtained at three different levels of the periodontal lesion (orifice, shallow--2 mm into the pocket; or base of lesion), and processed using PCR to identify 10 periodontal pathogens. The chi-square procedure was used to determine whether probe depth affected the distribution of bacterial counts observed. A repeated measures analysis of variance tested the hypotheses related to level of probe and microorganism on mean rank of bacterial counts. RESULTS: The effect of probe level on mean bacterial counts depends on the type of microorganism. Likewise, the effect of microorganism type on mean bacterial counts significantly depends on probe level, where sampling from 2 mm into the periodontal pocket was found to yield significantly higher results than sampling from the orifice. Overall mean counts of pathogenic microorganisms were found to differ significantly across the three probe depths. The microorganisms differed in their observed levels over all three probe levels. Further analysis found several significant differences that characterize the nature of the interaction between probe level and microorganism type. CONCLUSION: There is significant difference in the amount of putative periodontal pathogens at varying depths of the pocket when sampled with a periodontal curette.