comparison of crestal bone loss around dental implants placed in healed sites using flapped and...

Journal of Periodontology; Copyright 2014 DOI: 10.1902/jop.2014.140355

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Comparison of Crestal Bone Loss Around Dental Implants Placed in Healed Sites Using Flapped and Flapless Techniques: A Systematic Review

Fahim Vohra,* Abdul Aziz Al-Khuraif,† Khalid Almas,‡ Fawad Javed§

* Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.

† College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.

‡ Department of Periodontology, College of Dentistry, University of Dammam, Dammam, Saudi Arabia.

§ Eng. Abdullah Bugshan Research Chair for Growth Factors and Bone Regeneration, 3D Imaging and Biomechanical Laboratory, College of Applied Medical Sciences,

King Saud University, Riyadh, Saudi Arabia. Objective: The aim of the present systematic review was to compare the crestal bone loss

(CBL) around dental implants placed in healed sites using flapped and flapless surgical techniques.

Methods: The addressed focused question was “Does flapped and flapless surgical technique influence CBL around dental implants placed in healed sites? Databases were searched from 1975 up to and including May 2014 using different combinations of the following keywords: "crestal bone loss"; "dental implant"; "surgery"; "flap"; and "flapless". Unpublished data, experimental studies, letters to the editor, review articles, case reports, commentaries and articles published in languages other than English, were excluded. In all studies, the test group comprised of implants placed using flapless surgery and in the control group, implants were placed after reflection of a full thickness mucoperiosteal flap.

Results: Nine clinical studies were included. In six studies, CBL around implants was comparable among the test and control groups. In three studies, implants in the test group showed significantly less CBL as compared to the control group. In one study, CBL was significantly higher in the test group than the control group.

Conclusion: Crestal bone loss around dental implants placed in healed sites using flapped and flapless techniques is comparable.

KEY WORDS: alveolar bone loss; surgical flap; dental implants.

A traditional implant placement protocol involves exposure of the alveolar ridge using a full thickness mucoperiosteal flap, following which implants are placed in bone and the flaps repositioned using sutures.1, 2 Flap elevation facilitates visibility and access at the operating site and is considered advantageous in the esthetic zone since flaps can be repositioned to desired locations.3 However, reflection of mucoperiosteal flap compromises the vascular supply of bone, which may lead to crestal bone loss (CBL) and long-term esthetic complications.3-5

Studies6-8 have shown that a flapless procedure during implant placement has a positive effect on alveolar bone remodeling process. For example, in the study by Sunitha and Sapthagiri7, 40 patients selected for conventional implant therapy were assigned to two treatment groups, flapped and flapless respectively. The amount of CBL was measured at baseline and up to two years after implant placement using conventional two-dimensional radiographs. The results showed that CBL was


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significantly higher around implants placed after flapped surgery as compared to flapless implants.7 Similar results were reported by Tsoukaki et al.8, Job et al.6

and Tonetti and Schmid9. An explanation in this regard may be derived from the fact that using a flapless approach during implant placement preserves the periosteal vascular supply to bone thereby minimizing the possibility of future CBL. However, controversial results have also been reported. In the studies by Froum et al.10 and De Bruyn et al.11 CBL around implants placed in healed sites using flapped and flapless surgery were comparable.

To our knowledge from indexed literature, there is one recently published systematic review which compared the effect of flapped and flapless surgical techniques on CBL around dental implants.12 The results showed that the implant survival and radiographic CBL among flapped and flapless interventions were comparable. It is however noteworthy that studies on both immediate and conventionally placed implants were included in this systematic review.12 In addition, in one study bone augmentation procedures were also performed.13 It has been reported, as compared to implants placed in healed sites using flapless technique, a significant correlation exists between crestal bone loss and flapless immediate implants.12 This suggests that factors such as implant placement protocol (immediate or conventional) and surgical technique (flapped, flapless and/or bone augmentation procedures) influence the overall CBL around implants. Therefore, it is speculated that a systematic review primarily focusing on implants placed in either healed sites or fresh extraction sockets would clearly show the influence of flapped and flapless surgical technique on CBL.

With this background, the aim of the present systematic review was to compare CBL around dental implants placed in healed sites using flapped and flapless surgical techniques.

MATERIALS AND METHODS

Focused Question The addressed focused question was "Does flapped and flapless surgical technique influence CBL around dental implants placed in healed sites?”

Eligibility Criteria The following eligibility criteria were imposed: (a) original studies; (b) clinical studies; (c) intervention: CBL around dental implants placed in healed sites using flapped and flapless techniques; (d) presence of a test group (implants placed using flapless surgery) and a control group (implants placed using conventional full thickness mucoperiosteal flaps) in healed sites (e) articles published only in English language. Letters to the Editor, case reports, commentaries, review articles and unpublished articles were excluded.

Search Strategy PubMed/Medline (National Library of Medicine, Bethesda, Maryland), Google-Scholar, EMBASE and ISI Web of Knowledge databases were searched from 1975 up to and including May 2014 using different combinations of the following key words: “ crestal bone loss”, “ dental implant ”, “ surgery”, “flap” and “flapless”. Titles and abstracts of studies that fulfilled the eligibility criteria were individually assessed by


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the authors (FV, AK, KA and FJ) and checked for agreement. Full text of the relevant studies were then independently read and assessed with reference to the selection protocol. As a next step, reference lists of original and review studies were hand searched to identify any articles that could have been missed during the initial search. Any disagreements regarding study selection were resolved by discussion (Figure 1).

The initial search yielded 36 studies. Twenty-six studies, which did not fulfill our eligibility criteria were excluded (see supplementary Appendix 1 in the online Journal of Periodontology). In total, 10 studies6-8, 10, 11, 14-18 were included and processed for data extraction.

RESULTS

General Characteristics of the Studies All studies6-8, 10, 11, 14-18 had a prospective design and were performed either at universities and health care centers. The total number of patients ranged between 6 and 60 individuals. Seven studies7, 8, 11, 15-18 reported the mean age of study participants, which was between 39.2 years and 61 years (age range 20 to 79). Nine studies7, 8, 10, 11, 14-18 reported the number of female participants, which ranged between 7 and 35 individuals (Table 1). In the study by Katsoulis et al.15 and De Bruyn et al.11, 3 and 10 smokers respectively were included. In all studies6-8, 10, 11, 14-18 CBL was measured using standardized two-dimensional radiographs. In four studies10, 11, 15, 16 it remained unclear whether or not soft tissue biotype was assessed prior to implant placement.

Surgical Technique and Implant Related Characteristics In all studies,6-8, 10, 11, 14-18 rough surfaced titanium implants were placed in healed sites, with diameters and lengths ranging between 3.3 mm-5mm and 7mm-18 mm respectively. The number of implants placed ranged between 10 and 195. In four studies,7, 11, 14, 17 implants were placed in both arches. In three studies15, 16, 18 all implants were placed in the maxilla. In three studies,6, 8, 10 location of implants was not reported. Five studies11, 14, 15, 17, 18, reported the implant insertion torque, which ranged between 20Ncm-35Ncm. Immediate and conventional loading was performed in three6, 16, 17 and four7, 10, 11, 18 studies respectively. In three studies8, 14, 15 implant loading was not performed (Table 1). The follow up period ranged from 6 weeks up to 48 months.

In 5 studies10, 11, 14-16 CBL was comparable around implants placed using flapped and flapless techniques. In 4 studies6-8, 18 implants placed using flapless techniques showed significantly less CBL compared to those placed using flapped technique. In the study by Malo et al.17 implants placed using flapless techniques showed significantly higher CBL than those placed using flapped surgery.

DISCUSSION The present study was based on the hypothesis that implants placed in healed sites using flapless technique undergo significantly less CBL as compared to those placed using conventional surgical flap procedures. An explanation in this regard may be derived from the fact that as compared to flapped surgical procedures, flapless surgery allows minimum disruption of peri-implant tissues thereby reducing changes in crestal bone levels, probing depth and inflammation.19 In addition, flapless surgery


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has also been reported to preserve circulation of the peri-implant tissues and accelerate recuperation, thereby allowing the patient to resume regular oral hygiene maintenance procedure immediately after implant placement.7 The findings of the present systematic review are comparable to those reported in the study by Lin et al 12. However, Lin et al.12 included studies on implants placed in healed sites, fresh extraction sockets and augmented sites. Therefore, the present systematic review was performed using strict eligibility criteria to assess CBL around dental implants placed in healed sites using flapped and flapless surgical procedures.

Interestingly, 50% studies10, 11, 14-16 included in the present systematic review showed that CBL was comparable among implants placed either using flapped or flapless surgical technique. It is possible that additional factors, which may have influenced crestal bone levels were over-looked in the studies that fulfilled our eligibility criteria. For example, it is well-known that regular oral hygiene maintenance plays an essential role in the overall success of periodontal surgical interventions.20, 21 Although 211, 16 out of these 5 studies10, 11, 14-16 clearly stated that oral hygiene status was satisfactory in their study populations; it is speculated that all patients in these studies had acceptable pre and post-operative oral hygiene statuses. This could have yielded comparable results in terms of CBL among the groups. Likewise, studies22, 23 have also shown that CBL is significantly higher in smokers as compared to non-smokers. Among the studies10, 11, 14-16 showing comparable CBL among flapped and flapless implants, in only one study 16 all participants were non-smokers. In studies by Katsoulis et al.15 and De Bruyn et al.11 nearly 7% and 20% of the population, respectively comprised of smokers. However, the group allocation (flapped and flapless) of smokers remained unclear. It is possible that the comparable outcomes reported in these studies11, 15 could have been influenced by the distribution of smokers within their respective study groups. Moreover, clinical experience and skills of the surgeon are considered a prerequisite in the overall treatment success 3, 24,

25. In 60% of these studies11, 15, 16, surgical procedures were performed by a single skilled operator. Therefore, the operator’s skills seem to be an additional factor that governed CBL around dental implants regardless of the surgical techniques (flapped or flapless) used in these studies10, 11, 14-16. Furthermore, peri-implant soft-tissue biotype, implant abutment interface, depth of implant placement (crestal or sub-crestal) and occlusal loading are additional factors that could have biased the results of the studies included in the present review.26-29 It is noteworthy that none of the studies included in this review addressed the relationship of crestal bone levels with implant-abutment interface, depth of implant placement and occlusal loading independent of the surgical technique used (flapped or flapless). Also, in 410, 11, 15, 16 studies, it remained unclear whether the soft tissue biotype prior to implant placement was investigated.

A limitation of the studies included in the present review6-8, 10, 11, 14-18 is that all study participants were presumably healthy individuals. It is well-known that periodontal inflammatory conditions are worse in immunocompromised patients (such as patients with poorly controlled diabetes and pre-diabetes) and elderly patients as compared to systemically healthy and younger individuals.30-33 It may therefore be speculated that the outcomes of implant surgical procedures (regardless of the technique used) are compromised in immunosuppressed and elderly individuals as compared to systemically healthy counterparts. However, further studies are needed in this regard.


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CONCLUSION Within the limits of the present systematic review crestal bone loss around dental implants placed in healed sites using flapped and flapless techniques is comparable.

ACKNOWLEDGEMENT The authors would like to extend their appreciation to the Research Centre, College of Applied Medical Sciences and the Deanship of Scientific Research at King Saud University for funding this research.

REFERENCES 1. Branemark PI, Hansson BO, Adell R, et al. Osseointegrated implants in the treatment of the

edentulous jaw. Experience from a 10-year period. Scand J Plast Reconstr Surg Suppl 1977;16:1-132.

2. Albrektsson T, Branemark PI, Hansson HA, et al. Osseointegrated titanium implants. Requirements for ensuring a long-lasting, direct bone-to-implant anchorage in man. Acta Orthop Scand 1981;52:155-170.

3. Campelo LD, Camara JR. Flapless implant surgery: a 10-year clinical retrospective analysis. Int J Oral Maxillofac Implants 2002;17:271-276.

4. Gomez-Roman G. Influence of flap design on peri-implant interproximal crestal bone loss around single-tooth implants. Int J Oral Maxillofac Implants 2001;16:61-67.

5. Van der Zee E, Oosterveld P, Van Waas MA. Effect of GBR and fixture installation on gingiva and bone levels at adjacent teeth. Clin Oral Implants Res 2004;15:62-65.

6. Job S, Bhat V, Naidu EM. In vivo evaluation of crestal bone heights following implant placement with 'flapless' and 'with-flap' techniques in sites of immediately loaded implants. Indian J Dent Res 2008;19:320-325.

7. Sunitha RV, Sapthagiri E. Flapless implant surgery: a 2-year follow-up study of 40 implants. Oral Surg Oral Med Oral Pathol Oral Radiol 2013;116:e237-243.

8. Tsoukaki M, Kalpidis CD, Sakellari D, et al. Clinical, radiographic, microbiological, and immunological outcomes of flapped vs. flapless dental implants: a prospective randomized controlled clinical trial. Clin Oral Implants Res 2013;24:969-976.

9. Tonetti MS, Schmid J. Pathogenesis of implant failures. Periodontol 2000 1994;4:127-138.

10. Froum SJ, Cho SC, Elian N, et al. Survival rate of one-piece dental implants placed with a flapless or flap protocol--a randomized, controlled study: 12-month results. Int J Periodontics Restorative Dent 2011;31:591-601.

11. De Bruyn H, Atashkadeh M, Cosyn J, et al. Clinical outcome and bone preservation of single TiUnite implants installed with flapless or flap surgery. Clin Implant Dent Relat Res 2011;13:175-183.

12. Lin GH, Chan HL, Bashutski JD, et al. The effect of flapless surgery on implant survival and marginal bone level: a systematic review and meta-analysis. J Periodontol 2014;85:e91-103.

13. Covani U, Cornelini R, Barone A. Buccal bone augmentation around immediate implants with and without flap elevation: a modified approach. Int J Oral Maxillofac Implants 2008;23:841-846.

14. Al-Juboori MJ, Bin Abdulrahaman S, Jassan A. Comparison of flapless and conventional flap and the effect on crestal bone resorption during a 12-week healing period. Dent Implantol Update 2012;23:9-16.

15. Katsoulis J, Avrampou M, Spycher C, et al. Comparison of implant stability by means of resonance frequency analysis for flapless and conventionally inserted implants. Clin Implant Dent Relat Res 2012;14:915-923.

16. Van de Velde T, Sennerby L, De Bruyn H. The clinical and radiographic outcome of implants placed in the posterior maxilla with a guided flapless approach and immediately restored with a provisional rehabilitation: a randomized clinical trial. Clin Oral Implants Res 2010;21:1223-1233.


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17. Malo P, Nobre M. Flap vs. flapless surgical techniques at immediate implant function in predominantly soft bone for rehabilitation of partial edentulism: a prospective cohort study with follow-up of 1 year. Eur J Oral Implantol 2008;1:293-304.

18. Bashutski JD, Wang HL, Rudek I, et al. Effect of flapless surgery on single-tooth implants in the esthetic zone: a randomized clinical trial. J Periodontol 2013;84:1747-1754.

19. Oh TJ, Shotwell JL, Billy EJ, et al. Effect of flapless implant surgery on soft tissue profile: a randomized controlled clinical trial. J Periodontol 2006;77:874-882.

20. Serino G, Turri A, Lang NP. Maintenance therapy in patients following the surgical treatment of peri-implantitis: a 5-year follow-up study. Clin Oral Implants Res 2014;10.1111/clr.12418.

21. Lindhe J, Nyman S. The effect of plaque control and surgical pocket elimination on the establishment and maintenance of periodontal health. A longitudinal study of periodontal therapy in cases of advanced disease. J Clin Periodontol 1975;2:67-79.

22. Tatli U, Damlar I, Erdogan O, et al. Effects of smoking on periimplant health status and IL-1beta, TNF-alpha, and PGE2 levels in periimplant crevicular fluid: a cross-sectional study on well-maintained implant recall patients. Implant Dent 2013;22:519-524.

23. Vervaeke S, Collaert B, Vandeweghe S, et al. The effect of smoking on survival and bone loss of implants with a fluoride-modified surface: a 2-year retrospective analysis of 1106 implants placed in daily practice. Clin Oral Implants Res 2012;23:758-766.

24. Perry PA. Aesthetic placement of single-stage ITI implants using a tissue punch and a lateral bone condensing technique. J Oral Maxillofac Surg 2003;61:275-276.

25. Cushen SE, Turkyilmaz I. Impact of operator experience on the accuracy of implant placement with stereolithographic surgical templates: an in vitro study. J Prosthet Dent 2013;109:248-254.

26. Puisys A, Linkevicius T. The influence of mucosal tissue thickening on crestal bone stability around bone-level implants. A prospective controlled clinical trial. Clin Oral Implants Res 2013;10.1111/clr.12301.

27. Romanos GE, Javed F. Platform switching minimises crestal bone loss around dental implants: truth or myth? J Oral Rehabil 2014;41:700-708.

28. Hobkirk JA, Brouziotou-Davas E. The influence of occlusal scheme on masticatory forces using implant stabilized bridges. J Oral Rehabil 1996;23:386-391.

29. Chang M, Chronopoulos V, Mattheos N. Impact of excessive occlusal load on successfully-osseointegrated dental implants: a literature review. J Investig Clin Dent 2013;4:142-150.

30. Javed F, Al-Askar M, Al-Rasheed A, et al. Comparison of self-perceived oral health, periodontal inflammatory conditions and socioeconomic status in individuals with and without prediabetes. Am J Med Sci 2012;344:100-104.

31. Javed F, Nasstrom K, Benchimol D, et al. Comparison of periodontal and socioeconomic status between subjects with type 2 diabetes mellitus and non-diabetic controls. J Periodontol 2007;78:2112-2119.

32. Javed F, Thafeed Alghamdi AS, Mikami T, et al. Effect of glycemic control on self-perceived oral health, periodontal parameters, and alveolar bone loss among patients with prediabetes. J Periodontol 2014;85:234-241.

33. Javed F, Klingspor L, Sundin U, et al. Periodontal conditions, oral Candida albicans and salivary proteins in type 2 diabetic subjects with emphasis on gender. BMC Oral Health 2009;9:12.

Correspondence: Dr. Fahim Vohra. Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, P.O.Box 60169, Riyadh 11545, Saudi

Arabia. Tel: +966 53 291 1056 Email: [email protected] Submitted June 14, 2014; accepted for publication August 26, 2014.

Figure 1 –

Study selection criteria


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Table 1:

Characteristics of the studies that fulfilled the eligibility criteria. Authors et al.

No. of Patients

(n)

Mean age in years (range)

Females (n)

Study groups Total no. of

Implants (n)

Implant dimensions

(Width-Length) (in mm)

Implant surface

Loading protocol

Follow-Up

Outcome

Job et al.6 6 NA NA FG: 5 implants were placed 10 3,8/10-15 Rough Immediate, non-

functional

12 weeks Bone loss was significantly higher in FG as compared to FLG.

(35-55) FLG: 5 implants were placed

Sunitha and Sapthagiri7

40 39.2 (25-62)

15 FG: 20 Implants were placed

40 3.7-4.8/ 13-16 Up to 24 months

FLG showed significantly less CBL than FG FLG: 20 Implants were

placed NA Convention

al Tsoukaki et al.8

20 FG: 46.4 11 FG: 15 Implants were placed

30 3.5-4 / NA NA Up to 12 weeks

CBL was higher in FG than FLG

FLG: 47.4 (30-62)

FLG: 15 Implants were placed

Unloaded

Froum et al.10 60 NA 35 FG: 30 implants were placed

60 4.3-5.0/10-16 Rough Conventional

12 months

Bone loss was comparable between FG and FLG FLG: 30 implants were

placed DeBruyn et al.11

49 53 (20-79) 27 *Group 1: Implants placed with flap technique

53 3.3-5.0/7-18 Rough Conventional

Up to 48 months

Both group 1 and group 2 showed a mean bone loss of 1.35mm *Group 2: Implants placed

with flapless technique

Al-Juboori et al.14

10 NA 7 †FG: 11 implants were placed

22 4.1-4.8 / 10 Rough Unloaded Up to 12 weeks

No significant difference was seen in CBL between the two groups. (27-62) †FLG: 11 Implants were

placed

Katsoulis et al.15

40 61 (47-78) 16 FG: 110 implants placed in 23 patients with FT

195 3.5-4.3/ 10-13 NA Unloaded Up to 36 months

Both FG and FLG showed a mean bone loss of 1.5mm FLG: 85 implants in 17

patients with FLT


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Van de Velde et al.16

14 55.7 (39-75)

10 FG: 34 implants were placed

70 4.1-4.8/ 8-12 Rough FG: Delayed

Up to 18 months

Both FG and FLG showed a mean bone loss of 1.9mm FLG: 36 implants were

placed FLG:

Immediate Malo et al.17 41 45.5 (19-

79) 22 FG: 40 Implants were

placed 72 4.0/ 10-15 Rough Immediate 12

months FLG showed more marginal bone loss than FG FLG: 32 Implants were

placed Bashutski et al.18

24 FG: 52.8 (27-78)

14 FG: 12 Implants were placed

24 3.5-4/NA Rough Conventional

15 months

FLG showed significantly less CBL than FG FLG: 52.8

(22-76) FLG: 12 implants were placed

* Number of implants assessed in the group was not reported † Number of implants assessed in the group was not reported

NA: not available FG: Implants inserted using flap technique FLG: Implants inserted using flapless technique

CBL: crest bone loss


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comparison of crestal bone loss around dental implants placed in healed sites using flapped and...

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