Clinical study of flap design to increase the keratinized gingiva around implants: 4-year follow-up

Keratinized mucosa changes around one-stage implants: A prospective case series

BACKGROUND

The need of an adequate band of keratinized tissue (KT) to maintain periodontal health around teeth as well as around implants has been a debated topic over many years but still no conclusions have been drawn.

OBJECTIVES

This prospective case series evaluates the changes undergone by the keratinized mucosa (KM) and the soft tissue volume around non-submerged implants before the prosthetic rehabilitation.

MATERIAL AND METHODS

A total of 40 patients were included. The primary outcome was to analyze the width of the KM at both buccal and lingual aspects compared to the pre-existing KT in the edentulous ridge only in mandibular (pre)molar area. The mucogingival line was marked with a surgical pen and an intra-oral scanner was used to take the impression of the implant area the day of the surgery (T0, baseline) and before the crown placement (T1, 3 months). Buccal soft tissue volume was measured at 1, 3, and 5 mm apical to the healing abutment position and a comparison between T0 and T1 was performed. Student t-test was used according to the distribution of the data (Shapiro-Wilk).

RESULTS

The mean KT width at baseline was 4.54 ± 1.31 mm at buccal side and 5.04 ± 1.88 mm at lingual side. After 3 months, the mean KM values were 3.15 ± 1.03 mm and 3.72 ± 1.56 mm at the buccal and lingual aspects, respectively. The differences, 30.6% of KM reduction buccally and 26.1% of reduction lingually, were statistically significant for both sides.

CONCLUSIONS

Within the limitations of this investigation, it was observed that the KM width from the baseline to the 3 months follow up presented a significant dimensional change in both the buccal and lingual aspects, whereas buccal soft tissue volume showed an increase between baseline and follow up.

The gain in keratinized gingiva using apically positioned flap during implant placement with and without ridge augmentation: A comparative prospective study

OBJECTIVES

To evaluate whether ridge augmentation (RA) affects the gain in keratinized gingiva (KG) in implant surgery using a full-thickness apically positioned flap (fAPF).

MATERIAL AND METHODS

We conducted a prospective study from April 2017 to April 2019 recording patient- and implant-related factors. The subjects underwent fAPF during implant placement and were divided two groups: Group A, one-stage surgical protocol without RA; Group B, two-stage surgical protocol with RA. The initial width of KG and the width of KG at 1 week, 3 weeks, 3 months, and 6 months after surgery and baseline were measured using a paper ruler. Multivariable generalized estimating equation (GEE) models were estimated to evaluate RA effects on the gain in KG, the shrinkage amount of KG, and shrinkage ratio of KG after fAPF.

RESULTS

Seventy-nine participants with 203 implants were included. The baseline values of KG were 1.68 mm in Group A and 0.82 mm in Group B (p < 0.001). The results of the multivariable GEE demonstrated that the gain in KG, the shrinkage amount of KG, and the shrinkage ratio of KG showed no significant difference in groups (p > 0.05). The gain in KG was 1.92 ± 1.67 mm in Group A, 1.48 ± 1.36 mm in Group B. The total shrinkage amount and the shrinkage ratio of KG were 1.87 mm and 42.43%, respectively.

CONCLUSIONS

A fAPF is a reliable technique that enables significant increase in KG regardless of RA in implant surgery.

Effect of Using a Plastic Stent with Apically Repositioned Flap in Peri-Implant Soft Tissue Augmentation: A Randomized Controlled Clinical Trial

Objectives

This study aimed to clinically assess and compare the width of peri-implant keratinized mucosa following the use of a readymade plastic stent with apically repositioned flap versus conventional apically repositioned flap with papillary sparing incisions during single-stage implant placement protocol.

Materials and Methods

A total of 20 patients were enrolled in this study. In the test group, a prefabricated implant-retained stent was clipped on the healing abutment after implant surgery to reposition the keratinized tissue buccoapically. In the control group, simple interrupted sutures were applied instead of using a stent. After the surgical procedure, the width of the buccal keratinized mucosa was measured at the mesial, middle, and distal aspects of the healing abutment. The change in the width of the buccal keratinized mucosa was assessed at 3 months and 6 months.

Results

No statistically significant difference was found between the stent group and control group in 6 months' interval where p=0.840, where both groups showed the same mean value of 4.70 ± 0.35 and 4.70 ± 0.63, respectively. The percent of change in the width of KM was found to be higher in the stent group than in the control group with no statistical significance.

Conclusion

The use of a readymade plastic stent in combined full/partial-thickness apically repositioned flap shows to be effective in increasing the width of KM compared to the conventional technique. This trial is registered with NCT03754894.

Clinical and histological evaluations of alveolar ridge augmentation using a novel bi-layered porous polyethylene barrier membrane

Guided bone regeneration (GBR) is an effective alveolar ridge reconstruction technique used before or at implant placement. The combination of various barrier membranes and bone substitutes has been employed. This study aimed to perform a preliminarily evaluation of the safety and performance of a new nonabsorbable bi-layered porous polyethylene (PPE) membrane, in combination with a freeze-dried cortical bone allograft in posterior mandibular ridge augmentation. Fifteen adults who had combined posterior mandibular defects were included for ridge augmentation via GBR using PPE membrane and allograft before implant placement. The keratinized mucosa width (KW), ridge width (RW), ridge height (RH), distance from measurement matrix to bone (DMB), and horizontal alveolar width at 14.0 mm apical to the occlusal plane (HAW) were clinically measured at 15 intended implant sites before and after the augmentation. Fifteen biopsy specimens were harvested at the implant sites for histological analysis. All the subjects completed the whole study. The KW and RH showed minor gains by 0.2 ± 1.4 mm and 0.9 ± 2.3 mm respectively; however, no statistically significant differences were found between, before, and after the augmentation (P > 0.05). In contrast, the RW and HAW significantly increased by 4.8 ± 1.6 mm and 2.3 ± 1.7 mm, respectively, (P ≤ 0.001), while DMB significantly decreased by 1.0 ± 0.8 mm after treatment (P < 0.001). Histological analysis revealed that allograft underwent active bone remodeling. The PPE membrane was adequately safe and efficient to use with allograft in GBR for the reconstruction of combined ridge defects. Although some complications were observed, these were manageable and subsequently lead to successful implant placement for all the subjects. However, further randomized controlled trials are still needed to confirm these findings.

Conventional versus Digital Impressions for Full Arch Screw-Retained Maxillary Rehabilitations: A Randomized Clinical Trial

Background: The objective of this study was to compare conventional versus digital impressions for Full-Arch maxillary rehabilitations. Methods: Patients selected for this study were treated with full-arch screw-retained rehabilitations supported by six immediately loaded dental implants. Patients have been scheduled randomly into control (conventional impression group, CIG) and test (digital impression group, DIG) groups respectively for a fully conventional workflow and a fully digital workflow. In both groups, within 24 h, temporary prostheses were delivered. Four months after the implant positioning, the two groups dealt with the fabrication of definitive restorations: conventional pick-up was performed in the control group, and definitive digital impressions were carried out in the test group. The time involved following these two procedures was recorded. Patients underwent intraoral digital radiographs to evaluate the accuracy of the framework-implant connection, check for the presence of voids at the bar-implant connection and measure bone level. Criteria used to assess success at the prosthetic level were the occurrence of prosthetic maintenance, the absence of fractures of the acrylic resin superstructure and voids. Results: A total of 50 patients received immediately loaded prostheses supported by six implants (total 300 implants). A fixture and prosthetic survival rate of 100% was observed. All digital X-ray examinations revealed a bar-implant connection accuracy and no voids. Differences that were not statistically significant (p > 0.05) in marginal bone loss were found between control and test groups. Significantly less time was spent to perform digital impression procedure (p < 0.05). Conclusions: Clinical and radiological results of the test group advocate a satisfactory accuracy and predictability of the intraoral scanner (IOS) to be a reliable alternative in clinical practice for implant full-arch rehabilitations and suggest fabrication of definitive restorations with a successful marginal fit precision.

Delayed Implants Outcome in Maxillary Molar Region

BACKGROUND

The aim of the present study was to assess bone volume changes in maxillary molar regions after delayed implants placement.

MATERIALS AND METHODS

Patients presented large bone defects after tooth extractions. Reactive soft tissue was left into the defects. No grafts were used. Cone beam computed tomography (CBCT) scans were performed before tooth extractions, at implant placement (at 3 months from extraction) and 3 years after implant placement, bone volume measurements were assessed.

RESULTS

Bucco-lingual width showed a statistically significant decrease (p = .013) at implant placement, 3 months after extraction. Moreover, a statistically significant increase (p < .01) was measured 3 years after implant placement. No statistically significant differences (p > .05) were found between baseline values (before extraction) and at 3 years from implant placement. Vertical dimension showed no statistically significant differences (p > .05) at implant placement, 3 months after extraction. Statistically significant differences (p < .0001) were found between baseline values (before extraction) and at 3 months from implant placement as well as between implant placement values and 3 years later.

CONCLUSION

CT scans presented successful outcome of delayed implants placed in large bone defects at 3-year follow-up.