Implant Collar Surface Properties and Marginal Bone Loss

Osseointegration is an essential requirement for allowing the survival of dental implants in the jaw bone. Factors such as unfavorable stress distribution, surgical trauma, implant-abutment microgap, and bacterial infiltration can detrimentally affect osseointegration [1, 2] and accelerate bone loss.

According to the literature, most if not all implants will cause to some extent marginal bone Loss (MBL) during their lifetime [3]. Efforts have been made to reduce MBL and to avoid its associated complications. Studies have shown that several factors such as implant surface quality [4] implant neck macro and micro design [5] and crestal implant position (6) play particularly crucial roles in osseointegration.

Surface area may be increased using proper modification techniques, either by addition or subtraction procedures. Surface treatments can also be classified as mechanical, chemical, and physical methods. Surface treatments of dental implants are used to modify their topography and energy, resulting in improved wettability, increased cell proliferation and growth, and in accelerated osseointegration [7].

Alpha-Bio Tec.’s Sand blast Large grit Acid etch (SLA) implant surface is created through two processes: a sand- blasting process for a macro surface of 20-40 microns and a double thermal acid etching process to create micro pitting between 1-5 microns.

There is no consensus in the literature concerning the effectiveness of various implant surface neck configurations and their effect on MBL. The aim of this review is to compare the influence of machined and SLA neck surface on MBL levels during the implant’s existence in the bone.

Limited available data suggests that smooth surfaces (machined) are less involved in peri-implantitis than rough surface implants [8]. This observation is potentially supported by reduced plaque accumulation around the implants with a reduced roughness (9). However, further research has shown that surface porosity impacts on osseointegration by allowing direct 3D ingrowth of osteogenic cells into the implant, thereby strengthening the bone-implant interface [10].

Acid etched surfaces enhance the osseointegration by increasing cell adhesion and bone formation [7]. This hypothesis was demonstrated in in-vitro studies showing osteoblasts growing on SLA surfaces. These osteoblasts are highly differentiated bone cells, suggesting that this pitted surface enhances bone cell-implant integration [11].

Preclinical and clinical studies suggest that there are several factors that individually and cumulatively influence MBL levels. Therefore, studies have been conducted that typically combine two or more crestal neck features to evaluate the best combination of features to reduce MBL.

Certain studies did not confirm that a rough surface combined with a microthreaded neck has a positive effect on the MBL [12]. However, the majority of the reviewed works show a different picture.

Bratu et al. (2009) compared marginal bone loss between implants with SLA treatment and coronal microthreads and polished neck implants. The results showed statistically significant lower MBL in combined SLA/microthread implants.

Another study showed a greater bone loss in implants with a machined surface neck design without microthreads in the first year [9].

The long term study of Piao et al. showed that a rough surface with micro-threads at the coronal part of implant maintained the marginal bone level against functional loading better than implants without these two features after a follow up of one year [13] and confirmed these results after a three year follow up [14].

Additionally, Shin et al. (2006) have shown in their work that a rough surface and micro-threads at the implant neck not only reduce crestal bone loss but also help with early biomechanical adaptation against loading in comparison to the machined neck design. They concluded that a rough surface with microthreads at the implant neck is the most effective design in maintaining the marginal bone level against functional loading [15].

In another study, a correlation between collar design, implant placement and MBL in a canine model was evaluated. The study data showed that the placement of a polished area subcrestally facilitates higher rates of early MBL [6], whereas a rough implant surface placed at the bone level reduces the amount of this bone loss [16, 17].


Based on the reviewed literature, we can conclude that marginal bone changes around rough-surfaced micro-threaded neck implants are significantly lower than in polished or rough surfaced implants.

All Alpha-Bio Tec.'s implants have rough SLA surface and microgrooves which contribute to osseointegration and reduce MBL.


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2. Bengazi F, Lang NP, Caroprese M, Urbizo Velez J, Favero V, Botticelli D. Dimensional changes in soft tissues around dental implants following free gingival grafting: an experimental study in dogs. Clin Oral Implants Res. 2015 Feb;26 (2):176-82.

3. Albrektsson T, Zarb G, Worthington P, Eriksson AR. The long-term efficacy of currently used dental implants: a review and proposed criteria of success. Int J Oral Maxillofac Implants 1986;1:11–25.

4. Lai H-C, Zhuang L-E, Zhang Z-Y, Wieland M, Liu X. Bone apposition around two different sandblasted, large-grit and acid-etched implant surfaces at sites with coronal circumferential defects: an experimental study in dogs. Clin. Oral Impl. Res. 20, 2009; 247–253.

5. Penarrocha, M., Palomar, M., Sanchis, J.M., Guarinos, J. & Balaguer, J. (2004) Radiologic study of marginal bone loss around 108 dental implants and its relationship to smoking, implant location, and morphology. International Journal of Oral & Maxillofacial Implants 19: 861–867.

6. Alomrani AN, Hermann JS, Jones AA, Buser D, Schoolfield J, Cochran DL. The effect of a machined collar on coronal hard tissue around titanium implants: a radiographic study in the canine mandible. Int J Oral Maxillofac Implants. 2005 Sep-Oct;20(5):677-86.

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11. Kieswetter K, Schwartz Z, Hummert TW, Cochran DL, Simpson J, Dean DD, Boyan BD. Surface roughness modulates the local production of growth factors and cytokines by osteoblast-like MG-63 cells. J Biomed Mater Res 32, 1996, 55–63

12. Bassetti R., Kaufmann R., Ebinger A, Mericske-Stern R., Enkling N, Is a grooved collar implant design superior to a machined design regarding bone level alteration? An observational pilot study. Quintessence international March 2014

13. Piao, C.M., Lee, J.E., Koak, J.Y., Kim, S.K., Rhyu, I.C., Han, C.H., Herr, Y., Heo, S.J. (2009). Marginal bone loss around three different implant systems: radiographic evaluation after 1 year. Journal of Oral Rehabilitation 36: 748–54.

14. Lee SY, Piao CM, Koak JY, Kim SK, Kim YS, Ku Y, Rhyu IC, Han CH, Heo SJ. A 3-year prospective radiographic evaluation of marginal bone level around different implant systems. J Oral Rehabil. 2010 Jul;37(7):538-44.

15. Shin, Y.K., Han, C.H., Heo, S.J., Kim, S. & Chun, H.J. (2006) Radiographic evaluation of marginal bone level around implants with different neck designs after 1 year. International Journal of Oral & Maxillofacial Implants 21: 789–794.

16. Hartman GA, Cochran DL. Initial implant position determines the magnitude of crestal bone remodeling. J Periodontol. 2004 Apr;75(4):572-7.

17. Hanggi, M.P., Hanggi, D.C., Schoolfield, J.D,. Meyer, J., Cochran, D.L. & Hermann, J.S.Crestal bone changes around titanium implants. Part i: a retrospective radiographic evaluation in humans comparing two non-submerged implant designs with different machined collar lengths. Journal of Periodontology 2005; 76: 791–802.