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Soft and Hard Tissue Changes Around Laser Microtexture Single Tooth ImplantsdA Clinical and Radiographic Evaluation Dharmarajan Gopalakrishnan, BDS, MDS,* Vaibhav Joshi, BDS, MDS,† and Georgios E. Romanos, DDS, PhD‡

he loss of a single tooth compromises function and esthetics, and the disharmony of the dynamic occlusal equilibrium are the main reason for the need for tooth replacement.1 Implants have been used for decades successfully. One of the main focus in implant dentistry today is to reduce the healing period, improving the osseointegration process with new implant surfaces and biomaterials.2–6 Recently, studies have revealed that the periimplant connective tissue that is established after an implant surgery with Laser Lok (BioHorizons, Birmingham, AL) implant acts as an effective barrier to the apical migration of the epithelial attachment. This in turn translates by protecting the bone level by 1 mm of connective tissue. When natural tooth was compared, it had connective tissue attached to cementum through Sharpey fibers in a perpendicular plane.7–14 Earlier studies with osseointegrated implants describe collagen fibers as being parallel, in a circular matter to

T

*Professor and Head of the Department, Department of Periodontology and Oral Implantology, Dr. D. Y. Patil Dental College and Hospital, Dr. D. Y. Patil Vidyapeeth, Pune, India. †Senior Lecturer, Department of Periodontology & Oral Implantology, Santosh Dental College and Hospital, Santosh University, Ghaziabad, India. ‡Professor, School of Dental Medicine, Stony Brook University, Stony Brook, NY.

Reprint requests and correspondence to: Georgios E. Romanos, DDS, PhD, School of Dental Medicine, Stony Brook University, 106 Rockland Hall, Stony Brook, NY 11794-8705, Phone: (631) 632-8755, Fax: (631) 6323116, E-mail: [email protected] ISSN 1056-6163/14/02305-570 Implant Dentistry Volume 23  Number 5 Copyright © 2014 by Lippincott Williams & Wilkins DOI: 10.1097/ID.0000000000000134

Purpose: To investigate the periodontal parameters that affect the soft and hard tissues around Laser microtextured single tooth implants at 18 months after loading. Methods: Twenty Laser Lok implants were placed in 20 single missing tooth sites using a 2-stage protocol. Clinical Parameters included Plaque Index (PI), Gingival Index (GI), Probing Pocket Depth (PPD), Bleeding on Probing (BOP), and Crestal Bone Loss (CBL). Clinical and radiographic evaluation was done at loading, 12 months and 18 months after loading. The data collected were analyzed statistically. Results: The PI and GI during the entire follow-up period were well

controlled. Eighty-six percent of implant sites were free of BOP at loading and 87% of sites were free of BOP at 18 months. A significant increase in PPD was not observed. The mean CBL was 0.59 mm at the time of loading, 0.80 mm at 12 months, and 1.06 mm at 18 months. Conclusion: The Laser Lok implants showed minimal CBL at 18 months than the commonly accepted 1.5 to 2.0 mm. The periimplant soft tissue stability was maintained throughout the study. (Implant Dent 2014;23:570–575) Key Words: crestal bone loss, Laser Lok surface, periodontal parameters, periimplant soft tissue stability, single tooth implant restoration

the implant. The use of Laser Lok microchannels resulted in perpendicular, functional physical attachment of the connective tissue to the Laser Lok microchannel on the implant collar that helped to stabilize the bone level and reduce the loss of crestal bone.8 Owing to the results of various studies in the context of periimplant soft and hard tissue response to single tooth implant-supported restorations, an attempt has been made in this study to evaluate the efficacy of Laser Lok dental implants.

efficacy of Laser Lok surface treated implants on periimplant hard and soft tissues comparing the placement in conventional healed ridges and proximal natural tooth, over a period of 18 months.

AIM The aim of this study was to evaluate the clinical and radiological

MATERIALS

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METHODS

Twenty missing tooth sites were selected for the proposed study from among the Out Patients Department of the Department of Periodontics and Oral Implantology, Santosh Dental College and Hospital and were explained the whole study protocol.

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conscious patients, and ability to provide informed consent. Exclusion Criteria

Fig. 1. A, Grid x-ray taken at implant placement (baseline). B, Grid x-ray taken at 18 months.

Systemic diseases possibly affecting the healing process, that is, diabetes (regardless of control), metabolic bone disease, including postmenopausal women not on replacement hormone therapy, treatment with therapeutic radiation to head within past 12 months, pregnancy, severe bruxism or clenching habit, active infection or severe inflammation in the areas intended for implant placement, absence of keratinized tissue at implant site, need for antibiotic prophylaxis or preoperative antibiotic coverage, need for simultaneous hard or soft tissue grafting, unable or unwilling to comply with study procedures and visits, smokers, and patients with relevant medical history.

IMPLANT SYSTEM The used implant system was a tapered implant system (BioHorizons, Birmingham, AL) with following characteristic features. Fig. 2. Frequency distribution by tooth replaced by implant. Features

Proprietary Laser Lok microchannels, anatomically tapered implant body, patented reverse buttress threads, proven internal hex connection, implant diameter of range 3.8, 4.6, and 5.8 mm, implant length of range 7.5, 9, 10.5, 12, and 15 mm. Implant Surface

Laser Lok microchannels are a series of 8- and 12-mm grooves that are engineered onto the collar of tapered internal implants. Resorbable blast texturing surface provides a highly complex surface texture for increased stability and osseointegration.7 Fig. 3. Frequency distribution by implant size.

PRESURGICAL PROCEDURES Patient selection was based on the following criteria. Inclusion Criteria

Older than 18 years, 1 bounded edentulous space, ie, a single missing

tooth with intact proximal teeth with sufficient bone quality and quantity to allow for implant placement without bone augmentations, irrespective of sex and having good systemic health, cooperative, motivated and hygiene

Each individual was subjected to a full diagnostic workup including: A detailed case history record, study cast and complete clinical photographs, routine lab investigations, intraoral radiograph of the site, panoramic radiograph, and dental CT scan.

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Table 1. Comparison of Mean Scores of PI, GI, BOP, PPD, and CBL at the Start of Loading, 12 Months and 18 Months After Loading Mean

SD

SEM

Significance (P)

0.45 0.24 0.18

0.55 0.43 0.38

0.06 0.05 0.04

0.000*

months months

0.24 0.09 0.14

0.43 0.28 0.35

0.05 0.03 0.04

0.028*

months months

0.14 0.04 0.12

0.35 0.19 0.33

0.04 0.02 0.04

0.072

months months

1.99 2.59 2.56

0.52 0.61 0.59

0.06 0.07 0.07

0.000*

months months

0.59 0.80 1.06

0.34 0.37 0.30

0.05 0.06 0.05

0.000*

PI Loading After 12 months After 18 months GI Loading After 12 After 18 BOP Loading After 12 After 18 PPD Loading After 12 After 18 CBL Loading After 12 After 18

*Mean difference is significant at the 0.05 level.

SURGICAL PROCEDURE Patients were selected after the analysis based on the case history and radiographic evaluation. An aseptic surgical technique was followed. Antimicrobial prophylaxis included Amoxicillin, 500 mg twice daily for 5 days, was advised starting 1 hour before surgery and after surgery, analgesic treatment advised was Ibuprofen 400 mg twice daily for 3 days. All implants were placed by the same

surgeons (V.J., D.G.). Patients were operated under local anesthesia. Surgical site was examined. Implant length and diameter was selected for each patient based on individual clinical needs and radiographic and cone beam computed tomography (General Electric, Milwaukee, WI) analysis. Implant placement was performed at Stage 1 surgery, according to a conventional 2-stage protocol with at least 6 months of submerged healing in the

maxilla and 4 months in the mandible. After crestal incision on a healed site, a mucoperiosteal flap was elevated. Osteotomies were drilled with copious irrigation, and the implants were placed according to manufacturer’s instructions. A minimum insertion torque of 25 N$cm was used for all implants and they were clinically stable. Care was taken to ensure minimal surgical trauma to the soft tissue. Sutures (black braided nonabsorbable silk sutures 3-0; Ethicon, Norderstedt, Germany) placed after implant placement in Stage 1 were removed 10 to 14 days after surgery. Periapical radiographs were taken using paralleling and standardized method (using a Rinn holder). The occlusal platform allowed an occlusal registration to be made thus preserving source to object and object to film distances. The same holders were used throughout the study, and the exposure time and film developing method were also standardized12 immediately after implant placement during the follow-up visits. The plaque control protocol was established with rinses with 0.2% chlorhexidine digluconate solution twice daily during the healing period. The patients were recalled for professional plaque control weekly in the first month and then monthly until the end of the study. At Stage 2-surgery, implants were uncovered and tested for mobility manually using a hand instrument. Healing abutments (gingival formers) were placed for 2 to 4 weeks. Impressions were taken, and permanent abutments with the prosthesis were delivered. The soft tissue and bone level evaluation was done using clinical and radiographic parameters. All implants were restored with porcelain fused to metal crowns with porcelain occlusal surface. All single implant crowns were retained with zinc-polycarboxylate cement.

PARAMETERS ASSESSED

Fig. 4. Comparison of the mean value of the various indices and parameters at the start of loading, 12 and 18 months after loading.

Clinical parameters were recorded at a sole calibrated examiner. All the patients were subjected to evaluation under periodontal parameters, which included Plaque Index, (PI; Silness and Loe, 1964), Gingival Index (GI; Loe and Silness, 1963), Probing Pocket

IMPLANT DENTISTRY / VOLUME 23, NUMBER 5 2014 Depth (PPD), Bleeding on Probing (BOP), and Crestal Bone Loss (CBL). Clinical parameters were measured at loading, 12 and 18 months after loading. Radiographic evaluation was done at baseline (Fig. 1A), 12 and 18 months (Fig. 1B) after loading. Statistical Analysis

Data were collected, and statistical analysis was carried out by Statistical Package for Social Sciences (SPSS, version 16.0; IBM Corp., NY) ANOVA test, Bonferroni post-hoc multiple comparison test, independent t test, and chi-square test were used for statistical evaluation. The statistical significance of all tests was defined as P , 0.05.

RESULTS A total of 20 implants were placed in 13 patients, 8 males (40%) and 5 females (60%). Of the 20 single tooth implants placed, 3 (15%) were placed in maxilla and 17 (85%) in the mandible (Fig. 2). Twelve implants were 3.8-mm wide and 10.5-mm long, 4 were 3.8-mm wide and 12-mm long, 2 implants had the size 4.6/12 mm and 1 implant of 4.6/15 mm and 4.6/7.5 mm size each were used (Fig. 3). All were consecutive single tooth implants. One implant was placed using indirect sinus lift procedure in left upper second molar region. The clinical parameters were recorded by a calibrated examiner using a manual calibrated probe (UNC-15; Hu-Friedy, Chicago, IL). A total of 4 sites were examined around each implant for PI, GI, BOP, and PPD. A total of 80 sites were evaluated in 20 subjects. Two sites were examined around each implant for CBL. A total of 40 sites were evaluated in 20 subjects. The data were analyzed by using SPSS (version 16.0; IBM Corp.). The mean value for PI was found to be 0.45 6 0.55 at the start of loading, 0.24 6 0.43 after 12 months of loading, and 0.18 6 0.38 after 18 months of loading. The mean value for GI was found to be 0.24 6 0.43 at loading, 0.09 6 0.28 at 12 months after loading, and 0.14 6 0.35 at 18 months after loading. The mean value for BOP was 0.14 6 0.35 at the start of loading,

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Table 2. Comparison of Mean CBL: Mesial and Distal at the Start of Loading, 12 Months and 18 Months After Loading CBL Mesial Loading After 12 After 18 Distal Loading After 12 After 18

Mean

SD

SE

Significance (P)

months months

0.65 0.88 1.13

0.40 0.36 0.32

0.09 0.08 0.07

0.001*

months months

0.53 0.73 1.00

0.26 0.38 0.28

0.06 0.08 0.06

0.000*

*The mean difference is significant at the 0.05 level.

Table 3. Comparison of Mean CBL: Mesial and Distal During Loading, 12 Months and 18 Months After Loading Among Males and Females CBL

Gender

Mean

SD

SEM

Significance (P)

Mesial

Male Female Male Female

0.85 0.92 0.87 0.63

0.37 0.44 0.37 0.32

0.07 0.08 0.07 0.06

0.529

Distal

0.011*

*The mean difference is significant at the 0.05 level.

0.04 6 0.19 at 12 months after loading, and 0.12 6 0.33 at 18 months after loading. The mean PPD was 1.99 6 0.52 mm at the start of loading, 2.59 6 0.61 mm at 12 months after loading, and 2.56 6 0.59 mm at 18 months after loading. The mean CBL was 0.59 6 0.34 mm at the start of loading, 0.80 6 0.37 mm at 12 months after loading, and 1.06 6 0.30 mm at 18 months after loading (Table 1). The mean PI, GI, BOP, PPD, and CBL during loading, 12 months and

18 months after loading were compared using the ANOVA test (Fig. 4). The difference for mean PI, GI, PPD, and CBL was found to be statistically significant (P , 0.05), whereas the difference for the mean BOP was found to be statistically not significant (P . 0.05). Within the group comparison for mean PI, GI, BOP, PPD, and CBL during loading, 12 months and 18 months after loading was done using the Bonferroni post-hoc multiple comparison test.

Fig. 5. Comparison of mean CBL at the start of loading, 12 months and 18 months after loading among males, females, and overall.

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RADIOGRAPHIC PARAMETERS The mean mesial CBL during loading was at the beginning 0.65 6 0.40 mm, 12 months after loading was 0.88 6 0.36 mm, and 18 months after loading was 1.13 6 0.32 mm. The mean distal CBL during loading was at the start of loading 0.53 6 0.26 mm, 12 months after loading was 0.73 6 0.38 mm, and 18 months after loading was 1.00 6 0.28 mm. The comparison of mean mesial and distal CBL from the start of loading, 12 months and 18 months after loading was done using the ANOVA test. The difference was found to be statistically significant (P , 0.05) (Table 2). Within the group comparison for mean CBL on the mesial and distal side during loading, 12 months and 18 months after loading was done using the Bonferroni post-hoc multiple comparison test. There was a significant difference between the mean CBL on the mesial side at the start of loading and 18 months after loading (P , 0.05). There was a significant difference between the mean CBL on the mesial side at the start of loading, 12 and 18 months after loading (P , 0.05). The mean CBL: mesial and distal among males and females was compared using the independent t test. The difference for mean mesial CBL was found to be statistically not significant (P . 0.05), whereas the difference for mean distal CBL was found to be statistically significant (P , 0.05) (Table 3) (Fig. 5).

DISCUSSION This study focused on dimensional alterations of the periimplant hard and soft tissues during 2-stage implant procedure supporting single tooth restorations. Twenty tapered implants with laser-treated surfaces (Laser Lok) were used successfully and evaluated for 18 months after loading. Implants monitored to date were clinically stable (100% survival rate) when tested at follow-up evaluations and did not show evidence of periimplant radiolucency on periapical radiographs, signs of implant fracture, symptoms and signs of pathology, or persistent or irreversible signs,



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and symptoms of pain, infection, neuropathies, paresthesia, or violation of mandibular canal. For periimplant evaluation, PI, GI, BOP, and PPD have been found to be important periodontal parameters for the assessment of implant success that has been reported previously by many researchers.11–14 However, none of these studies revealed the specificity of periodontal indices for periimplant soft tissues based on a long-term controlled follow-up. The interface of implant surface and connective tissue is different from natural teeth because of the absence of periodontal ligament. It may, therefore be expected that periodontal parameters around natural teeth and around implant fixtures are not same.11–18 This study has used an implant design with laser microtextured surface collar. Previous studies using the same implant system and scanning electron microscopy from retrieved implants in humans showed that laser microtextured surface collar produced a connective tissue attachment around the collar portions of the implant.19–21 This was also confirmed in our study showing an excellent soft tissue behavior around the collar of the implants. The PI during the follow-up period in this study was well monitored, showing very low clinical values during the entire observation period. Similar results were found for the GI. BOP at the periimplant soft tissues has been considered as an early symptom of disease activity.22,23 The mean BOP was observed very low in the entire loading period. The mean value of BOP shown in this study at the time of loading and at 18 months is lesser than the values presented in previous studies.24,25 Furthermore, despite the prescribed postoperative use of chlorhexidine mouth rinse in nonperiodontitis patients with good overall hygiene, 86% of implant sites were free of BOP at loading, and 87% of implant sites were free of BOP at 18-month follow-up.11,14 A significant increase in PPD was not observed with time in this study, indicating that the implant mucosa was kept in healthy condition from the beginning of the study. PPD is one of

the fundamental parameters of periodontal examination. Mean PPD at the 18-month examination was 2.56 mm. Compared with the healthy natural dentition, the mean PPD of the periimplant mucosa in this study was slightly higher. PPD depends on the degree of penetrability of the tissue by the probe. It is suggested therefore, that periimplant mucosa is more penetrable than that around natural teeth.11,14,22 Our follow-up implant evaluation also included conventional dental radiographies. The mesial and distal crestal bone levels on each implant were evaluated using standardized dental radiographs as the distance from the implant shoulder to the first visible alveolar bone contact (CBL).23 The mean CBL was 0.59 mm at the start of loading, 0.80 mm at 12-month and 1.06 mm at 18-month follow-up examination. Conventional radiography reveals only 2-dimensional information. Therefore, tissue breakdown on buccal or lingual aspects may be missed. The mean amount of bone loss that occurred in the first year of loading was minimal in comparison with the mean bone loss that occurred between the time of implant placement and the time of final prosthesis delivery.9,24 A study in 200923 evaluated CBL around 75 two-piece implants that were restored according to platform switch protocol. Their 12-month radiographic analysis revealed vertical bone loss between 0.6 and 1.2 mm (mean, 0.95 6 0.32 mm). This also corresponds with our study stating a mean value for CBL at mesial side 12 months after loading to be 0.88 6 0.36 mm and at distal side after 12 months of loading to be 0.73 6 0.38 mm.9 Thus, the trend in this study that the largest amount of marginal bone change occurred between the time of implant placement and the final prosthesis delivery was very consistent. The results demonstrated a 100% success rate for 20 Laser Lok microtextured dental implants followed over a period of 18 months after loading. In general, a clinically significant marginal bone remodeling occurred between the time of implant placement and final prosthesis delivery with subsequent crestal

IMPLANT DENTISTRY / VOLUME 23, NUMBER 5 2014 bone maintenance around the implant up to 18 months. This also suggests that the factors that influence early healing around the implant are significantly different from those that affect later marginal bone remodeling. Identification of these factors and the mechanism involved are interesting future topics to be addressed.

CONCLUSION The primary goal of this study was to determine long-term success rate of a dental implant, which provides anchorage for a single tooth restoration based on the response of the tissues present around the implant. The study demonstrated that the laser microtextured collar of the implant prevents the apical migration of the soft tissues by creating a mucogingival seal around the implant collar and crestal bone maintenance.

DISCLOSURE The authors claim to have no financial interest, either directly or indirectly, in the products or information listed in the article.

ACKNOWLEDGMENTS The authors would like to acknowledge BioHorizons, Birmingham, AL, for providing the implant materials for this study.

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A clinical and radiographic 12-month prospective study. Int J Periodontics Restorative Dent. 2003;23:313–323. 4. Jung UW, Choi CY, Kim CS, et al. Evaluation of mandibular posterior single implants with two different surfaces: A 5-year comparative study. J Periodontol. 2008;79:1857–1863. 5. Cochran DL. A comparison of endosseous dental implant surfaces. J Periodontol. 1999;70:1523–1539. 6. Joly JC, de Lima AF, da Silva RC. Clinical and radiographic evaluation of soft and hard tissue changes around implants: A pilot study. J Periodontol. 2003;74: 1097–1103. 7. Cardaropoli G, Lekholm U, Wennström JL. Tissue alterations at implant-supported single tooth replacements: A 1-year prospective clinical study. Clin Oral Implants Res. 2006;17:165–217. 8. Shapoff CA, Lahey B, Wasserlauf PA, et al. Radiographic analysis of crestal bone levels around Laser-Lok collar dental implants. Int J Periodontics Restorative Dent. 2010;30:129–137. 9. Cochran DL, Nummikoski PV, Schoolfield JD, et al. A prospective multicenter 5-year radiographic evaluation of crestal bone levels over time in 596 dental implants placed in 192 patients. J Periodontol. 2009;80:725–733. 10. Kwon HJ, Lee DW, Park KH, et al. Influence of the tooth- and implant-side marginal bone level on the interproximal papilla dimension in a single implant with a microthread, conical seal, and platformswitched design. J Periodontol. 2009;80: 1541–1547. 11. Nishimura K, Itoh T, Takaki K. Periodontal parameters of osseointegrated dental implants. A 4-year controlled follow-up study. Clin Oral Implants Res. 1997;8:272–278. 12. Hosseinzadeh A, Savabi O, Nassiri F. Average annual crestal bone loss of ITI implants following the first year of loading. J Res Med Sci. 2006;11:146–150. 13. Pecora GE, Ceccarelli R, Bonelli M. Clinical evaluation of laser microtexturing for soft tissue and bone attachment to dental implants. Implant Dent. 2009;18:57–66. 14. DeAngelo SJ, Kumar PS, Beck FM, et al. Early soft tissue healing around one-stage dental implants: Clinical and microbiologic parameters. J Periodontol. 2007;78:1878–1886.

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15. Weiner S, Simon J, Ehrenberg DS, et al. The effects of laser microtextured collars upon crestal bone levels of dental implants. Implant Dent. 2008;17:217–228. 16. Wennström JL, Ekestubbe A, Gröndahl K, et al. Implant-supported singletooth restorations: A 5-year prospective study. J Clin Periodont. 2005;32:567–574. 17. Schropp L, Kostopoulos L, Wenzel A, et al. Clinical and radiographic performance of delayed-immediate single-tooth implant placement associated with periimplant bone defects. A 2-year prospective, controlled, randomized follow-up report. J Clin Periodontol. 2005;32: 480–487. 18. Sunitha RV, Ramakrishnan T, Kumar S, et al. Soft tissue preservation and crestal bone loss around single-tooth implants. J Oral Implantol. 2008;34: 223–229. 19. Nevins M, Nevins ML, Camelo M, et al. Human histologic evidence of a connective tissue attachment to a dental implant. Int J Periodontics Restorative Dent. 2008;28:111–121. 20. Botos S, Yousef H, Zweig B, et al. The effects of laser microtexturing of the dental implant collar on crestal bone levels and peri-implant health. Int J Oral Maxillofac Implants. 2011;26:492–498. 21. Ricci JL, Grew JC, Alexander H. Connective-tissue responses to defined biomaterial surfaces. I. Growth of rat fibroblast and bone marrow cell colonies on microgrooved substrates. J Biomed Mater Res A. 2008;85:313–325. 22. Welander M, Abrahamsson I, Linder E, et al. Soft tissue healing at titanium implants coated with type I collagen. An experimental study in dogs. J Clin Periodontol. 2007;34:452–458. 23. Kim TH, Lee DW, Kim CK, et al. Influence of early cover screw exposure on crestal bone loss around implants: Intra individual comparison of bone level at exposed and non-exposed implants. J Periodontol. 2009;80:933–939. 24. Bouri A Jr, Bissada N, Al-Zahrani MS, et al. Width of keratinized gingiva and the health status of the supporting tissues around dental implants. Int J Oral Maxillofac Implants. 2008;23:323–326. 25. Carrión JB, Barbosa IR. Single implant-supported restorations in the anterior maxilla. Int J Periodontics Restorative Dent. 2005;25:149–155.

Soft and hard tissue changes around laser microtexture single tooth implants--a clinical and radiographic evaluation.

To investigate the periodontal parameters that affect the soft and hard tissues around Laser microtextured single tooth implants at 18 months after lo...
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