Long-term case studies using a Laser-Lok® implant

Case Studies , Current Issue
Editor’s intro: Dr. Cary A. Shapoff illustrates several cases using Laser-Lok microchannel technology to preserve crestal bone and soft tissue esthetics. 

Dr. Cary A. Shapoff shares patient cases involving a surface treatment shown to attract a true, physical connective tissue attachment

Abstract

Numerous published animal and human dental implant studies report crestal bone loss from the time of placement of the healing abutment to various time periods after restoration. The bone loss can result in loss of interproximal papilla and recession of crown margins. These case examples demonstrate the long-term results that can be obtained utilizing a variety of implant and abutment styles and sizes with the Laser-Lok® (BioHorizons®) microchannel collar design to preserve crestal bone and soft tissue esthetics. Case 1 involved extraction, socket grafting, 6-month delayed implant placement, and final restoration in 6 months. This case was the first reported use of laser-microchannel technology (Laser-Lok) and justified the continued use and documentation of numerous other case examples in a private practice setting.

Figures 1 and 2: Case 1 — 1. Tooth No. 9 prior to extraction. 2. Radiograph imme-diately after surgical placement of implant (1 mm LL collar) and 0.5 mm coverscrew and Figure 3: Baseline radiograph imme-diately after placement of final crown

 

Figure 4: Bone level maintained on Laser-Lok collar 18 years after restoration (left) and Figure 5: Clinical view — Laser-Lok implant restoration at 19 years after surgical placement (right)

Case 1 (Figures 1-5)

First reported use of a Laser-Lok implant

A 34-year-old female presented with external resorption at the level of the cementoenamel junction (CEJ) of tooth No. 9. Various treatment options were presented, and the patient elected extraction and dental implant placement. After atraumatic extraction, the socket anatomy did not allow for immediate placement with acceptable initial stability. The socket was grafted with allograft calcified bone and allowed to heal for 6 months. At that time, a dental implant with a 1 mm Laser-Lok microchannel collar design was placed. A subepithelial connective tissue graft was also utilized on the adjacent tooth No. 10 for root coverage. Six months after placement, second-stage surgery was performed, and the tooth was restored with a customized abutment and PFM crown. Note the maintenance of excellent crestal bone levels on the Laser-Lok microchannel collar (within 0.5 mm of the implant/abutment interface) at 19 years post-restoration. The soft tissue margins have remained stable and exhibit excellent periodontal health.

Case 2 (Figures 6-10)

A 45-year old female presented with non-restorable caries under existing crown on tooth No. 7. Treatment decision: Single tooth implant — immediate extraction, immediate placement with provisional loading utilizing BioHorizons Plus (platform-switched) implant (4.6 x 12 mm with 3.5 mm platform).

Figures 6 and 7: Case 2 — 6. Initial radiograph. 7. Radiograph following extraction, immediate implant placement (BioHorizons Plus) with provisional loading with PEEK abutment (left) and igure 8: Radiograph at placement of final crown on CAD/CAM-milled titanium Laser-Lok abutment and Figure 9: Case 2 — Radiograph at 5 years after restoration. Note stable crestal bone (right)

Figure 10: Clinical photograph of final restoration with healthy and stable soft tissue on Laser-Lok microchannel implant abutment at 5 years. (Restoration by Dr. David J. Wohl, Fairfield, Connecticut)

Case 3 (Figures 11-14)

Two adjacent BioHorizons Laser-Lok dental implants (4.6 mm x 12 mm)

A 52-year-old female patient presented with maxillary central incisors that were deemed non-restorable and replacements with dental implant restorations selected after discussing restorative options.

Figures 11-13: Case 3 — 11. Initial radiograph (2012). 12. Radiograph of screw-retained provisional crowns with lexan plastic provisional abutments (four months after implant placement). Note interproximal bone levels at initial time of provisional restoration. 13. Radiograph 5 years after implant placement and restoration (2019)

Figure 14: Clinical view 5 years after final restorations. (Restorations by Dr. Jeffrey O’Connell, Fairfield, Connecticut)

Cases 4 and 5 (Figures 15-23)

Clinical use of laser-microtextured CAD-CAM abutments

Figures 15 and 16: Case 4 — 15. Initial radiograph of non-restorable tooth No. 9. Extraction and immediate implant placement with provisional loading. 16. Radiograph at 5 years post-restoration (left) and Figure 17: Clinical photo (5-years post-restoration) demonstrating stable and healthy soft tissue around laser-microtextured implant and abutment. This was the first reported case utilizing the laser-microtextured Ti-base CAD-CAM abutment (right)

Figures 18-20: Case 5 — 18. Male, age 21, Initial radiograph of tooth No. 7 with mid-root horizontal fracture. Extraction with delayed placement after extraction socket bone grafting. 19. Radiograph at initial time of provisional loading. Note interproximal crestal bone levels. 20. Five-year post-restoration radiograph utilizing a BioHorizons 3.0 mm x 12 mm microchannel implant with Laser-Lok Ti-base abutment with a CAD-CAM abutment

Laser-Lok overview

Laser-Lok microchannels are a proprietary dental implant surface treatment developed from over 25 years of research, initiated to create the optimal implant surface. Through this research, the unique Laser-Lok surface has been shown to elicit a biologic response that includes the inhibition of epithelial downgrowth and the attachment of connective tissue.2-10 This physical attachment produces a biologic seal around the implant that protects and maintains crestal bone health. The Laser-Lok phenomenon has been shown in post-market studies to be more effective than other implant designs in reducing bone loss.11,12,13,14,27

Unique surface characteristics

Laser-Lok microchannels are a series of cell-sized circumferential channels that are precisely created using proprietary laser ablation technology. This technology produces extremely consistent microchannels that are optimally sized to attach and organize both osteoblasts and fibroblasts.15-25 The Laser-Lok microstructure also includes a repeating nanostructure that maximizes surface area and enables cell pseudopodia and collagen microfibrils to interdigitate with the Laser- Lok surface.

Different from other surface treatments

Virtually all dental implant surfaces on the market are grit-blasted and/or acid-etched. These manufacturing methods create random surfaces that vary from point to point on the implant and alter cell reaction depending on where each cell comes in contact with the surface.10 While random surfaces have shown higher osseointegration than machined surfaces,11,26 only the Laser-Lok surface has been shown using light microscopy, polarized light microscopy, non-human and human histologic specimens, and scanning electron microscopy to also be effective for inhibiting epithelial downgrowth and formation of connective tissue attachment.2-10

Figure 21: Laser-Lok implant with SEM image at 39X showing the Laser-Lok zone

Figure 22: Laser-Lok at 800X exhibits consistently formedmicrochannels to organize and promote tissuegrowth2-10,16,17 (left) and Figure 23: The uniformity of the Laser-Lok micro-structure and nanostructure is evident using extreme magnification (right)

Figure 24: Colorized SEM of a dental implant harvested at 6 months with connective tissue physically attached and interdigitated to the Laser-Lok surface2 (left), Figure 25: Colorized SEM of Laser-Lok microchannels showing superior osseointegration5 (middle, and Figure 26: Colorized histology of a fully lased implant thread at 3 months showing complete bone attachment5 (right)

Table 1: In a 3-year multicenter prospective study, the Laser-Lok surface showed superior bone maintenance over identical implants without the Laser-Lok surface11 and Figure 27: Laser-Lok esthetic abutments

Figure 28: Histology of a Laser-Lok abutment on an RBT implant with a machined collar showing exceptional bone growth at 3 months6

Figure 29: Comparative histologies show the biologic differences between standard abutments and Laser-Lok abutments including changes in epithelial downgrowth, connective tissue, and crestal bone health6

The clinical advantage

The Laser-Lok surface has been shown in several studies to offer a clinical advantage over other implant designs. In a prospective, controlled multi-center study, Laser-Lok implants, when placed alongside identical implants with a traditional surface, were shown at 37 months post-op to reduce bone loss by 70% (or 1.35 mm).11 In a retrospective, private practice study, Laser-Lok implants placed in a variety of site conditions and followed up to 3 years minimized bone loss to 0.46 mm.12 In a prospective, University-based overdenture study, Laser-Lok implants reduced bone loss by 63% versus NobelReplace™ Select.13

Latest discoveries

The establishment of a physical, connective tissue attachment to the Laser-Lok surface has generated an entirely new area of research and development: Laser-Lok applied to abutments. This provides an opportunity to use Laser-Lok abutments to create a biologic seal and Laser-Lok implants to establish superior osseointegration15 — a solution that offers the best of both worlds. Alternatively, Laser-Lok abutments can support peri-implant health around implants without Laser-Lok. Multiple pre-clinical and clinical studies support both concepts.5-9 Laser-Lok abutments can inhibit epithelial downgrowth — physically attach connective tissue to protect and maintain crestal bone. Most recently, the combination of Laser-Lok abutments, implants, and platform switching was shown to regenerate crestal bone surrounding the implant.5 Cases 4 and 5 demonstrate the use of the Ti-base laser-microtextured abutments with the titanium base and the custom zirconia core abutment. These cases have maintained exceptional crestal bone and excellent soft tissue contours during the 5-year follow-up period.

Acknowledgments

Restorations for cases 1 and 4 by Jeffrey A. Babushkin, DDS (Trumbull, Connecticut). Restorations for cases 2 and 5 by David J. Wohl DDS, (Fairfield, Connecticut). Restorations for case 3 by Jeffery D. O’Connell, DMD (Fairfield, Connecticut).

Before his microchannel technology experiences, Dr. Cary Shapoff wrote about treating compromised sites with narrow implants. Read his article here.