Volumetric variation of peri-implant soft tissues in convergent collar implants and crowns using the biologically oriented preparation technique (BOPT).

BACKGROUND: To evaluate the changes in the peri-implant soft tissues of convergent collar implants with biologically oriented preparation technique (BOPT) crowns, 10 months after loading. MATERIAL AND METHODS: A pilot study was carried out from January 2016 to October 2017 involving 14 patients with one or two implants in the posterior mandibular sector. A total of 32 convergent collar implants were placed using a non-submerged protocol. Three months later the provisional cemented crowns were fitted using the BOPT approach with the finish line 1-1.5 mm below the gingival margin, simulating coronal emergence of a natural tooth. The soft tissue changes were measured with an intraoral scanner at two different timepoints: a) on the day of provisionalization, before prosthetic loading; and b) 10 months later without the provisional prosthesis. The STL files were superimposed and the soft tissue changes were recorded using a color scale with measurement of the volumetric changes in mm3. RESULTS: A mean increase in peri-implant mucosal volume of 64.7 mm3 was observed in 29 implants. The zones with the greatest increase in soft tissue volume were the papillae of implants with adjacent teeth and the peri-implant buccal margin. Three implants showed a mean decrease in soft tissue volume of -25.1 mm3. CONCLUSIONS: The fitting and design of crowns using the biologically oriented preparation technique (BOPT) over convergent collar implants affords a significant increase in peri-implant soft tissue volume both at the level of the papillae and in the buccal margin.

Effect on osseointegration of two implant macro-designs:A histomorphometric analysis of bicortically installed implants in different topographic sites of rabbit's tibiae.

BACKGROUND: To evaluate the effect of two different implant macro-designs on the sequential osseointegration at bicortically installed implants in the rabbit tibia. A further aim is to compare the osseointegration at different topographic zones. MATERIAL AND METHODS: 27 New Zealand rabbits were implemented. Two implants, one for each macro-design (Ticare Inhex® or Ticare Quattro®, Mozo-Grau, Valladolid, Spain), were randomly implanted in the diaphysis or metaphysis of each tibia. The flaps were sutured to allow a submerged healing. The animals were sacrificed after 2, 4 or 8 weeks. Ground sections were prepared and analyzed. RESULTS: No statistically significant differences were found between the two groups for newly formed bone in contact with the implant surface, being about 16%, 19% and 33% in both groups, after 2, 4, and 8 weeks of healing. Bone apposition was slightly higher in the diaphysis, reaching values of 36.4% in the diaphysis, and 29.3% in the metaphysis at 8 weeks of healing. It was observed that the implant position showed a statistical significance regarding BIC values at 4 and 8 weeks (p<0.05). Multivariate analysis fails to detect statistical significant differences for the interaction between implant designs and topographic site. Ticare Quattro® design had a slight better BIC values at diaphysis sites across healing stages, but without reaching a statistical significance. CONCLUSIONS: The both implant macro-designs provided similar degrees of osseointegration. Bone morphometry and density may affect bone apposition onto the implant surface. The apposition rates were slightly better in diaphysis compared to metaphysis.

A prospective clinical study of polycarboxylate cement in periapical surgery.

OBJECTIVE: To evaluate the clinical efficacy of polycarboxylate cement as retrograde filling material. DESIGN: A prospective clinical study was made of 25 patients subjected to periapical surgery with ultrasound and magnifying loupes, in which polycarboxylate cement was used as retrograde filling material. Measurements were made of the area and diameter of the lesions pre- and postoperatively, and 6 and 12 months after the operation. The apical resection and retrograde filling areas were also measured, and the prognosis following surgery was recorded. RESULTS: A total of 23 patients with 31 apicoectomized teeth were studied (2 patients being lost to follow-up). The mean area of the periapical lesions before surgery was 52.25 mm2, with a mean major diameter of 6.1 mm and a mean lesser diameter of 4.8 mm. The success rate after 12 months was 54.7%, according to the criteria of Von Arx and Kurt. The prognosis was poorer in females, in larger lesions, and in cases with larger retrograde filling areas. CONCLUSIONS: Polycarboxylate cement offers good results, with important bone regeneration after periapical surgery.