Contour angle and peri-implant tissue height: Two interrelated features of the implant supracrestal complex

OBJECTIVES

Recent research has suggested the contour of the prosthesis and the vertical height of the peri-implant mucosa as important parameters that can influence the long term health and stability of the peri-implant tissue. In particular, overcontouring of the prosthesis has been correlated with an increased risk for peri-implantitis, while reduced soft tissue height has been associated with marginal bone loss, recession, and other soft tissue complications. Although these two parameters have been investigated as independent in the current literature, clinical experience points toward a close interrelation between transmucosal tissue height and prosthesis contour angle. It is often found that a reduced vertical height of the implant supracrestal complex is the main reason for overcontouring of the prosthesis. At the same time, achieving a favorable contour of 30o or less is not possible unless the clinician has ensured an adequate vertical height of the soft tissue. The purpose of this short communication is to establish the relation between tissue vertical height and prosthesis contour by utilizing a theoretical geometry equation based on the Pythagorean theorem. In doing so, one can use the dimensions of the implant as well as those of the prosthesis at the mucosal margin to calculate the essential vertical height for achieving a favorable prosthesis contour.

CONCLUSIONS

As the treatment plan of the implant supracrestal complex is "top-down," in case of deficient vertical height, subcrestal placement of the implant should be considered to achieve a proper prosthesis contour.

Immediate implant placement vs. early implant treatment in the esthetic area. A 1-year randomized clinical trial

OBJECTIVES

To assess the impact of implant placement and temporization timing on esthetic outcomes of single maxillary anterior implants with intact bone walls and interproximal bone.

MATERIALS AND METHODS

Test group patients received an immediate implant with immediate provisional restoration and socket preservation, while patients in the control group received an early implant placement with guided bone regeneration and delayed loading. Patients were followed for 1 year after final prosthetic and pink esthetic score (PES), mid-buccal mucosal level (MBML), crestal bone changes (CBC), and peri-implant soft tissue parameters, and patient chair time was recorded.

RESULTS

Fifty patients received the intended treatment (25 test and 25 control). No implants failed. PES after 1 year was 12.8 ± 1.19 for the test group and 12.5 ± 1.36 for the control group (p = .362). MBML difference between baseline (after final crown delivery) and the 1-year follow-up was gain of 0.2 ± 1.02 mm for the test group (p = .047) and no change in the control group. CBC after 1 year were 0.1 mm ± 0.21 mm (mesial) and 0.2 mm ± 0.22 mm (distal) for the test group and 0.2 mm ± 0.25 mm (mesial) and 0.3 mm ± 0.19 mm (distal) for the control group, p = .540 (mesial) and p = .462 (distal). Test group required half the chair time (127 ± 13 min) when compared to the control group (259 ± 15 min, p < .001).

CONCLUSIONS

Within the limits of this trial, both treatment protocols resulted in excellent esthetic outcomes with PES >12 after 1-year follow-up.

Full versus partial thickness flap to determine differentiation and over keratinization of non-keratinized mucosa. A 3-year split mouth randomized pilot study

Objectives

It was shown, that Connective Tissue Grafts (CTG) retrieved from the tuberosity tends to determine hyperplastic responses and may induce a beneficial over‐keratinization of non‐keratinized mucosa. Clinically evaluate and compare CTG from tuberosity ability to increase soft tissue thickness and the keratinization potential after recipient area is either prepared using split or full thickness flap in edentulous mandible.

Materials and methods

Fourty implants were placed in 10 edentulous patients with atrophied mandible (Class IV of Misch) presenting less than 1.0 mm of keratinized tissue using a flapless approach and immediately restored with acrylic temporary bridge on multi‐unit abutments. The surgical sites were split‐mouth randomized and prepared as CTG recipients by a tunneling procedure. Twenty benefited of a partial thickness approach and 20 of a full thickness one. The CTG was placed buccally using partial thickness or full thickness flap according to the randomization schedule. The width of keratinized tissue (KT), the horizontal soft tissue thickness (STT), the marginal hard and soft tissue levels as well as the implant success parameters were collected and analyzed.

Results

After a 3 year follow‐up period the increase of KT was statistically significantly (p < 0.001) larger in the partial thickness group from 0.6(0.6) to 5.1(0.72) mm, while full thickness group showed very little improvement from 0.5(0.51) to 1(0.57) mm (p < 0.001). STT was significantly increased in both groups over time: from 2.4(0.88) to 5.4(0.68) mm in full thickness group and from 2.5(0.51) to 5.8(0.41) mm in partial thickness group without any significant difference between the groups.

Conclusion

The increase of soft tissue thickness by using CTG from tuberosity was found in both groups, while keratinization of non‐keratinized mucosa appeared more in the partial thickness group.

Decompression technique - A modified approach for lateral alveolar ridge augmentation: A case report

A particular technique can increase the mucosal and peri-implant bone thickness, prevent compression around implant neck, and obtain proper space for the following prosthetic treatment with an adequate emergence profile.

Crestal bone stability after flapless placement of sloped implants with immediate temporization in edentulous mandible. A prospective comparative clinical trial

Objectives

The purpose of this study was to evaluate crestal bone stability around sloped implants using the flapless procedure and compare it with conventional implants placed axially.

Materials and methods

A total of 40 bone‐level implants with platform switching were used for this study for 10 patients (4 males and 6 females) in edentulous mandible. Twenty mesial conventional implants were placed in upright position and 20 distal 30° sloped implants tilted 30°. Bone loss was estimated using radiographic imaging after a 6‐ and a 12‐month follow‐up period. Comparison of the bone loss in the distal and mesial region at both implantation angles were conducted to understand the nature and progression of crestal bone loss.

Results

Crestal bone loss around the sloped implants was 0.29 mm (SD = 0.292) on average, while around conventional implants it was 0.22 mm (SD = 0.202) after one‐year follow‐up. However, there was no significant difference in the average of crestal bone loss between two trial groups after 6 months (p < 0.243) and one‐year (p < 0.614) follow‐up. The results indicated a 100% implant survival rate after one‐year follow‐up. Additionally, three fixed prostheses needed realignment after fracturing during the follow‐up time.

Conclusion

Considering the limitations of this study, it can be presumed that sloped and conventional implants with platform switching and conical connection have the same potential for minimal crestal bone loss.

Early crestal bone loss: Is it really loss?

Bone remineralization around dental implants might be possible after early crestal bone loss.