Proposal regarding potential causes related to certain complications with dental implants and adjacent natural teeth: Physics applied to prosthodontics.

PURPOSE: Complications can and do occur with implants and their restorations with causes having been proposed for some single implant complications but not for others. METHODS: A review of pertinent literature was conducted. A PubMed search of vibration, movement, and dentistry had 175 citations, while stress waves, movement, and dentistry had zero citations as did stress waves, movement. This paper discusses the physics of vibration, elastic and inelastic collision, and stress waves as potentially causative factors related to clinical complications. RESULTS: Multiple potential causes for interproximal contact loss have been presented, but it has not been fully understood. Likewise, theories have been suggested regarding the intrusion of natural teeth when they are connected to an implant as part of a fixed partial denture as well as intrusion when a tooth is located between adjacent implants, but the process of intrusion, and resultant extrusion, is not fully understood. A third complication with single implants and their crowns is abutment screw loosening with several of the clinical characteristics having been discussed but without determining the underlying process(es). CONCLUSIONS: Interproximal contact loss, natural tooth intrusion, and abutment screw loosening are common complications that occur with implant retained restorations. Occlusion is a significant confounding variable. The hypothesis is that vibration, or possibly stress waves, generated from occlusal impact forces on implant crowns and transmitted to adjacent teeth, are the causative factors in these events. Since occlusion appears to play a role in these complications, it is recommended that occlusal contacts provide centralized stability on implant crowns and not be located on any inclined surfaces that transmit lateral forces that could be transmitted to an adjacent tooth and cause interproximal contact loss or intrusion. The intensity, form, and location of proximal contacts between a natural tooth located between adjacent single implant crowns seem to play a role in the intrusion of the natural tooth. Currently, there is a lack of information about the underlying mechanisms related to these occurrences and research is needed to define any confounding variables.

Placement of immediate implants and a fixed provisional restoration to replace the four mandibular incisors.

A new approach to the replacement of four mandibular incisors with localized, chronic, severe periodontitis is proposed in this clinical report. Their replacement with immediately placed implants and a nonocclusally loaded provisional restoration is a simple, predictable, and successful treatment modality. Data from 10 consecutive clinical cases are presented, and a 100% implant survival rate is reported for a 6-year period of follow-up. Treatment outcomes for this approach compare favorably with alternative treatment options and should be considered an important primary treatment option for most patients requiring the replacement of the four mandibular incisors.

Flapless Postextraction Socket Implant Placement: The Effects of a Platform Switch-Designed Implant on Peri-implant Soft Tissue Thickness-A Prospective Study.

This paper presents the results of a prospective study on the clinical effect of grafting the buccal gap with platform switching, following flapless tooth extraction and immediate implant placement and provisional restoration, on (1) alterations in buccolingual ridge dimension and (2) midfacial peri-implant soft tissue thickness. Fifty-six patients were placed in one of four treatment groups: (1) a non-platform-switching implant (Non-PS, n = 14); (2) a non-platform-switching implant and bone graft (BG/Non-PS, n = 14); (3) a platform-switching implant (PS, n = 15); and (4) a platform-switching implant and bone graft (BG/PS, n = 13). Buccolingual ridge dimensional change and peri-implant soft tissue thickness at 2 mm below the free gingival margin were measured. Both PS and BG/PS groups showed an increase in buccolingual dimension compared to the contralateral natural tooth site as well as peri-implant soft tissue thickness of > 2.5 mm, clinically. Platform switching was associated with significantly greater midfacial soft tissue thickness than bone grafting (mean ± standard deviation: 2.17 ± 0.04 for Non-PS and 3.55 ± 0.14 for PS). Using platform-switched implants, in conjunction with immediate implant placement and immediate provisional restoration, was associated with a significantly greater stability of ridge dimension and peri-implant soft tissue thickness than using non-platform-switched implants when measured 12 months after placement of the final restoration. Platform switching may help achieve preservation of ridge dimension and enhance the stability of peri-implant soft tissue following immediate implant placement and provisional restoration without bone grafting. Further research is required to assess the long-term outcome.

Cyst in Alveolar Mucosa Adjacent to a Dental Implant Following Connective Tissue Grafting for Ridge Augmentation.

INTRODUCTION: When the soft tissue around an implant is inadequate or poorly contoured, soft tissue augmentation techniques such as connective tissue grafts are used to enhance the gingiva and gingival contour around an implant-supported restoration. There have been some case reports of cystic lesions occurring after a connective tissue graft, but this appears to be the first case report of a cyst in alveolar mucosa adjacent to an implant. CASE PRESENTATION: Following the placement of implants in the #6 and #7 positions, a cosmetic soft tissue deficiency was visible and inadequate papilla height was evident interproximally. The #7 implant was subsequently submerged, and multiple connective tissue grafts were placed to reconstruct the soft tissue on the buccal aspect of #5 to #7. Four years later the patient returned for evaluation of a 6 × 3 mm raised, fluid-filled vesicle on the alveolar mucosa, buccal to the submerged #7 implant. A submarginal incision with a semilunar design was placed from #6 to #8. A 6 × 3.5 mm cystic-appearing lesion was enucleated from the inner aspect of the flap opposite the submerged #7 implant and sent for biopsy. Histologic evaluation showed the lesion to be a gingival cyst of the buccal mucosa. CONCLUSION: While subepithelial connective tissue grafting is highly predictable, complications can occur. What causes the epithelium to proliferate and subsequently develop into a cyst is still unknown.