George Deryabin and Simonas Grybauskas, International Journal of Implant Dentistry, 2020
Purpose: The aim of this clinical trial was to evaluate the influence of gingival tissue thickness oncrestal bone loss around dental implants after a 1-year follow-up.
Materials and Methods:Forty-siximplants (23 test and 23 control) were placed in 19 patients. The test implants were placed about 2 mm supracrestally, whereas the control implants were positioned at the bone level. Before implant placement, the tissue thickness at implant sites was measured with a periodontal probe. After healing,metal-ceramic cement-retained prostheses were constructed. According to tissue thickness, the test implants were divided into A (thin) and B (thick) groups. Intraoral radiographs were performed andcrestal bone changes were measured at implant placement and after 1 year.
Results: Mean bone lossaround the test implants in group A (thin mucosa) was 1.61 ± 0.24 mm (SE; range, 0.9 to 3.3 mm) onthe mesial and 1.28 ± 0.167 mm (range, 0.8 to 2.1 mm) on the distal. Mean bone loss in test group B(thick mucosa) implants was 0.26 ± 0.08 mm (range, 0.2 to 0.9 mm) on the mesial aspect and 0.09 ±0.05 mm (range, 0.2 to 0.6 mm) on the distal aspect. Mean bone loss around control implants was 1.8 ±0.164 mm (range, 0.6 to 4.0 mm) and 1.87 ± 0.166 mm (range, 0.0 to 4.1 mm) on the mesial and distalaspects, respectively. Analysis of variance revealed a significant difference in terms of bone lossbetween test A (thin) and B (thick) groups on both the mesial and the distal.
Conclusion: Initial gingivaltissue thickness at the crest may be considered as a significant influence on marginal bone stability around implants. If the tissue thickness is 2.0 mm or less, crestal bone loss up to 1.45 mm may occur,despite a supracrestal position of the implant-abutment interface.INTJ ORALMAXILLOFACIMPLANTS2009;24:712–719
Key words:biologic width, crestal bone loss, dental implants, microgap, mucosal thickness.
Read full article HERE.
Purpose: The aim of this pilot study was to determine what effect thin mucosal tissues can have oncrestal bone stability around implants with platform switching.
Materials and Methods: Twelve 2-piece implants, consisting of 6 implants with horizontally matching implant-abutment connection (control) and 6 implants with platform switching (test) were placed in 4 patients. The mean age of the patients was 43 years (range, 37 to 56 yrs). Mucosal tissue thickness atimplant sites was measured to be 2 mm or less. Implants were restored with 5 splinted crowns and single 3-unit ﬁxed partial denture. Intraoral radiographs were obtained and crestal bone changes were mea-sured at implant placement and after a 1-year follow-up post-treatment. The statistical signiﬁcance level was set to P less than .05.
Results: Bone loss around the test implants was 1.81 +/- 0.39 mm on the mesial site and 1.70 +/- 0.35 mmon the distal aspect. Control implants overcame marginal bone resorption equaling 1.60 +/- 0.46 mm onthe mesial site and 1.76 +/- 0.45 mm on distal measurement. No statistically signiﬁcant difference wasfound between control and test implants either mesially (F[1,10]=0.746; P =.408) or distally (F[1,10]=0.080; P =.783).
Conclusion: Within the limitations of this pilot study it can be concluded that implants with platformswitching did not preserve crestal bone better in comparison with implants with traditional implant-abutment connection if, at the time of implant placement, thin mucosal tissues were present.
Read full article HERE.
Purpose: The aim of this paper was to distinguish what kind of mucosal tissue, measured at the top of the crest can be referred to as thin, medium or thick and its influence on crestal bone loss around dental implants after a 1-year follow-up.
Materials and methods: Totally 64 implants were evaluated in 26 patients. 32 implants (test group) were placed about 2 mm supracrestally and 32 implants (control group) were positioned equal to the bone level. Mucosal tissues at a time of implant placement were divided into 3 groups–thin, medium and thick. Crestal bone changes were measured at implant placement and after a 1-year follow-up.
Results: Mean bone loss around test implants in thin tissue group (up to 2 mm) was 1.35 mm+/-0.33 SD, in medium thickness group mean bone loss was 0.32 mm+/-0.44 SD and 0.12 mm+/-0.16 SD of bone loss was registered in thick tissue group (3.1 mm and more). Mean bone loss around control implants in all 3 groups was as follows: 1.8 mm+/-0.52 SD in thin, 1.62 mm+/-0.63 SD in medium and 1.55 mm+/-0.47 SD in thick tissue group. ANOVA analysis showed statistically significant differences between 3 groups of thickness, as crestal bone loss around test implants is concerned. (F[2,29]=37.3; P=.000). In control implants bone loss did not vary between 3 groups of tissue thickness (F[2,29]=0.73; P=.503).
Conclusions: It can be concluded that initial tissue thickness can influence crestal bone changes around implants.
Read full article HERE.
Mantas Vaitiekūnas, Darius Jegelevičius, Andrius Sakalauskas and Simonas Grybauskas. Appl. Sci. 2020, 10, 236.
Due to technical aspects of Cone Beam Computed Tomography (CBCT), the automatic methods for bone segmentation are not widely used in the clinical practice of endodontics, orthodontics, oral and maxillofacial surgery. The aim of this study was to evaluate method’s accuracy for bone segmentation in CBCT data sets. The sliding three dimensional (3D) window, histogram filter and Otsu’s method were used to implement the automatic segmentation. The results of automatic segmentation were compared with the results of segmentation performed by an experienced oral and maxillofacial surgeon. Twenty patients and their forty CBCT data sets were used in this study (20 preoperative and 20 postoperative). Intraclass Correlation Coefficients (ICC) were calculated to prove the reliability of surgeon segmentations. ICC was 0.958 with 95% confidence interval [0.896 … 0.983] in preoperative data sets and 0.931 with 95% confidence interval [0.836 … 0.972] in postoperative data sets. Three basic metrics were used in order to evaluate the accuracy of the automatic method—Dice Similarity Coefficient (DSC), Root Mean Square (RMS), Average Distance Error (ADE) of surfaces mismatch and additional metric in order to evaluate computation time of segmentation was used. The mean value of preoperative DSC was 0.921, postoperative—0.911, the mean value of preoperative RMS was 0.559 mm, postoperative—0.647 mm, the ADE value of preoperative cases was 0.043 mm, postoperative—0.057 mm, the mean computational time to perform the segmentation was 46 s. The automatic method showed clinically acceptable accuracy results and thus can be used as a new tool for automatic bone segmentation in CBCT data. It can be applied in oral and maxillofacial surgery for performance of 3D Virtual Surgical Plan (VSP) or for postoperative follow-up.
Cintra O, Grybauskas S, Vogel CJ, Latkauskiene D, Gama Jr NA. Dental Press J Orthod. 2018 May-June;23(3):80-93.
Dentofacial deformities usually are surgically treated, and 3D virtual planning has been used to favor accurate outcomes. Cases reported in the present article show that orthognathic surgery carried out to correct facial asymmetries does not comprise only one treatment protocol. 3D virtual planning might be used for surgical planning, but it should also be used to diagnose the deformity, thus allowing for an analysis of the best-recommended possibilities for the orthodontic preparation that suits each individual case.