Dental Implant Osseointegration Inhibition by Nicotine through Increasing nAChR, NFATc1 Expression, Osteoclast Numbers, and Decreasing Osteoblast Numbers

Abstract

Objective The success of dental implants is determined by the osteointegration process. Many studies state that smoking cigarettes can inhibit osseointegration, but the inhibition mechanism is still unclear.

The aim of this study was to identify and analyze the effect of nicotine on the inhibition of dental implant osseointegration through the expression of nicotinic acetylcholine receptor (nAChR), nuclear factor of activated T cells cytoplasmic 1 (NFATc1), osteoclast, and osteoblast numbers.

Materials and Methods This study is an experimental study of 16 New Zealand rabbits, randomized across two groups. Group 1 (eight rabbits) was a control group, and group 2 (eight rabbits) was a treatment group. The treatment group was given 2.5 mg/kg body weight/day of nicotine by injection 1 week before placement of the implant until the end of research. Observations were made in the first and the eighth week by measuring the number of osteoblast and osteoclast by immunohistology test and the expression of nAChR and NFATc1 by immunohistochemistry test.

Statistical Analysis Data was analyzed using a one-way analysis of variance and Student's t-test. A p-value of < 0.05 was considered statistically significant.

Results Significant differences were found between the control and treatment groups (p < 0.05). Results showed that nicotine increases the expression of nAChR and decreases the number of osteoblasts and the expression of BMP2 and osteocalcin.

Conclusion Nicotine inhibits the osseointegration of dental implants by increasing nAChR, NFATc1, osteoclast numbers, and decreasing osteoblast numbers.

Keywords

dental implant - nicotine - nAChR - NFATc1 - osteoclast - osteoblast - osseointegration

Introduction

Dental implants are the gold standard for the replacement of missing teeth. Many factors have been recognized as critical for the successful performance of the implants. One of the most important factors is osseointegration—the direct interactions between the implant and the tissues. The osseointegration depends on the osteoblastic activity enhancement around the implant that promotes direct union between the implant and the bone. The success rate of osseointegration of dental implants depends on many factors such as oral hygiene, operator skills, implant materials used, bone quality and quantity, occlusal load, lack of medical condition, and personal oral habits such as smoking.[1] [2] Smoking is considered one of the major causes of the failure of dental implants.[3] [4] [5] [6]

Smoking is a high-risk factor and contributes to the causes of oral diseases, including periodontitis, which usually presents as alveolar bone resorption.[7] Nicotine is a major component of tobacco that regulates alveolar bone metabolism by increasing periodontal tissue attachment loss and alveolar bone absorption, increasing periapical disease, inducing peri-implantitis, and decreasing bone regeneration rate after tooth extraction or surgery.[4] [8] [9] Nicotine affects initial implant survival rates and early osseointegration.[10] [11] [12] The higher the duration and frequency of smoking, the higher the rate of marginal bone loss around the dental implant.[13] Nicotine contributes to an increase in osteoclastic activity that causes bone loss. The harmful effects of nicotine can be so detrimental that it affects wound healing and ultimately affects implant osseointegration.[14]

Bone remodeling is a physiological process that involves a balance between bone formation and bone destruction regulated by osteoblasts and osteoclasts.[15] [16] The activated T cell nucleus factor, cytoplasm 1 (NFATc1), which is the master transcription factor for osteoclast formation, can induce osteoclast differentiation in the absence of RANKL.[17] NFATc1-deficient osteoclast precursors cannot differentiate into osteoclasts, but ectopic expression of NFATc1 causes osteoclast differentiation.[18] Osteoclastogenesis is also regulated by nicotinic acetylcholine receptors (nAchRs). nAChRs have been identified in osteoblasts and osteoclasts cells that are known to be essential for maintaining bone homeostasis.[19]

The mechanisms behind the effect of nicotine on dental implant osseointegration are not fully understood. Some studies have shown that nicotine inhibits bone metabolism, while others have shown a biphasic effect.[20] Therefore, the purpose of this study was to identify and analyze the effect of nicotine on the inhibition of osseointegration of dental implants on the expression of nAChR, NFATc1, osteoclast, and osteoblast numbers.

Materials and Methods

Preparation of Experimental Animals

This study was an experimental study that designed a posttest control group. Sixteen healthy New Zealand White male rabbits 3.5 to 5.0 months old and weighing 2.5 to 3.5 kg were acclimatized for 7 days. Rabbits were housed in cages and given the same standard food and water ad libitum before, during, and after treatment.

Rabbits were randomly divided into two groups, a control group and a treatment group, each consisting of eight rabbits. Each group was divided into two small groups, 1 week and 8 weeks. In the treatment group, nicotine was induced by injecting a dose of 2.5 mg nicotine hydrogen tartrate salt per kg body weight (BW) (Sigma-Aldrich, United Kingdom). The control group was not given a nicotine induction.

Dental Implant Insertion

All rabbits were weighed to determine the required dose of anesthesia. All rabbits were anesthetized by intramuscular injection with a total dose of 0.15 mL xylazine per kg BW and 0.2 mL ketamil per kg BW.

Before placing the implant, the jawbone was marked and drilled into the bone to a depth of 7 mm at a speed of 1,200 revolutions per minute. An implant (SG, South Korea) with a diameter of 3.3 mm and a length of 7 mm was placed on the bone. Rabbits were injected with long-acting antibiotics (Medoxy-LA) at 0.1 mL/kg BW.

Sample Collection

At weeks 1 and 8, after implant insertion, all rabbits were euthanized with 0.2 mL ketamine by the dose of 10 mg/kg BW. Osseointegration values were measured by examining the stability of the implant using the ISQ Osstell tool. The number range on the Osstell tool was 1 to 100. If the Osstell tool shows more than 55, it is considered to have osseointegration and no osseointegration when less than 55. Osteoclast and osteoblast counts were examined from the mandibular section using Meyer's hematoxylin and eosin staining (Sigma-Aldrich).

Expression of nAChR and NFATc1 was performed using immunohistochemical staining with monoclonal primary antibody anti-nAChR (LSBio, United States) and anti-NFATc1 (Sigma, United States) marked by a brown color in the cell cytoplasm. Expression of nAChR and NFATc1 from cells was calculated by observing 10 different fields of view under a microscope at 400× magnification.

Data Analysis

Data on the number of osteoblasts and osteoclasts, nAChR, and NFATc1 expression are expressed as mean ± standard deviation and statistics by analysis of variance and Student's t-test using SPSS software package version 17.0. A p-value of < 0.05 was considered to show a statistically significant difference.

Results

The effect of nicotine on osseointegration of dental implants was examined, and the results are shown in [Table 1]. In the first week, there was no significant difference between the control and nicotine groups (p > 0.005), but in the 8th week, the osseointegration value in the treatment group was lower than in the control group (p < 0.005).

Table 1 The value of osseointegration at week 1 and 8

Variable	Time	Group (n = 8)	Mean	SD	p
Osseointegration	Week 1	Control	51.38	0.744	0.997
		Nicotine	51.13	0.991
	Week 8	Control	65.63	2.134	0.000
		Nicotine	52.13	2.031

Abbreviation: SD, standard deviation.

Osteoclast numbers increased in the nicotine group at weeks 1 and 8 compared with the control group (p < 0.005). Osteoblast numbers in the nicotine groups were decreased compared with the control groups at weeks 1 and 8 (p < 0.005) ([Table 2]). The results show that expression of nAChR and NFATc1 was higher in the 1st and 8th week nicotine groups than in the control group (p < 0.005) ([Table 3]).

Table 2 The number of osteoclasts and osteoblasts cells at week 1 and 8

Variable	Time	Group (n = 8)	Mean	SD	p
Osteoclast	Week 1	Control	13.00	2.390	0.000
		Nicotine	18.63	4.104
	Week 8	Control	10.50	1.773	0.000
		Nicotine	29.63	2.875
Osteoblast	Week 1	Control	21.13	2.360	0.000
		Nicotine	10.50	1.770
	Week 8	Control	27.88	2.950	0.000
		Nicotine	6.88	2.360

Abbreviation: SD, standard deviation.

Table 3 The expression of nAChR and NFATc1 at week 1 and 8

Variable	Time	Group (n = 8)	Mean	SD	p
nAChR	Week1	Control	5.38	2.667	0.000
		Nicotine	12.00	1.773
	Week 8	Control	5.00	2.390	0.000
		Nicotine	18.50	2.976
NFATc1	Week 1	Control	4.50	2.000	0.000
		Nicotine	11.25	3.240
	Week 8	Control	3.50	1.690	0.000
		Nicotine	11.25	22.510

Abbreviations: nAChR, nicotinic acetylcholine receptor; NFATc1, nuclear factor of activated T cells cytoplasmic 1; SD, standard deviation.

Discussion

This study shows that nicotine inhibits the osseointegration of dental implants by decreasing osteoblast numbers and increasing osteoclast numbers. Nicotine exposure increased the expression of nAChR and also the expression of NFATc1.

After dental implant insertion, mechanical trauma and bone damage caused by inflammation stimulate bone cells to produce cytokines and growth hormones to repair the damage. Bone healing around the implant involves a cascade of cellular and extracellular biological events at the interface between the bone and the implant until the surface of the implant is covered with newly formed bone. This biological process is regulated by growth and differentiation factors released at the bone-implant interface.[21] [22]

In this study, we found that osseointegration was inhibited by nicotine induction. Nicotine is more likely to spread and has a negative effect on bone healing. The osseointegration process requires the recruitment of osteoblasts, their fixation, adhesion, diffusion, proliferation, and differentiation into osteoblasts that secrete extracellular matrix calcification on the implant surface. All of these cellular events are sensitive to local and systemic effects of nicotine.[23]

Osteoblast activity was reduced in the experimental group compared with the control group. These results are consistent with those of Kim et al and Shibli et al who reported that nicotine suppresses the proliferation of osteoblasts.[10] [24] Nicotine acts as a stimulant and inhibitor of bone metabolism. Nicotine reduces the activity of osteoblasts and affects the collagen that can be used to form the extracellular matrix. Nicotine can also induce microvascular obstruction and reduce blood cell proliferation that impairs healing areas after implant placement.[25] Nicotine also reduces macrophage proliferation and increases susceptibility to infection at the surgical site of implant placement.[26] Another study states that nicotine concentration alters the effect of nicotine on implant osseointegration. Low nicotine levels stimulate osteoblast proliferation, increased the expression of osteocalcin, type 1 collagen, and alkaline phosphatase, but high levels have the opposite effect.[13] Conversely, Pereira et al found that exposure to nicotine adversely affected osteoblast activity.[23]

This study demonstrated that nicotine also promotes osteoclast formation. This finding is supported by Henemyre et al, who states that exposure to nicotine increases osteoclast differentiation and calcium phosphate absorption during bone regeneration.[27] Nicotine can affect osteoclast formation through several mechanisms. In contrast, Adler and Attia found that nicotine does not stimulate the formation of osteoclasts in rat bone marrow.[28]

In this study, nicotine induction increased nAChR expression. nAChR has been identified in cells essential for maintaining bone homeostasis, such as osteoblasts and osteoclasts.[19] Recently, several studies have linked nAChR to the regulation of osteoclast formation.[29] [30] [31] [32] nAChR agonists such as nicotine and carbachol choline have been shown to stimulate osteoclast formation.[29] [33] [34] In addition, nAChR antagonists block most of the effects of nicotine, suggesting that these changes are dependent on nAChR activation.[35]

We also found that nicotine induction increased NFATc1 expression. NFATc1 is a master transcription factor of osteoclast regulators involved in osteoclast formation and osteoclast activation.[36] Induction of nicotine induces excessive osteoclast activity and bone resorption, impairing osseointegration of dental implants. RANK induces the NFATc1 gene in osteoclasts via transcription factors such as the nuclear factor kappa B and c-Fos.[33] The important role of NFATc1 in osteoclast differentiation is well documented by several studies. Inhibition of NFATc1 by cytochalasin Z11 inhibits RANKL-induced osteoclast formation.[37] Even NFATc1-deficient embryonic stem cells cannot differentiate into osteoclasts in response to RANKL. However, NFATc1-ectopic osteoclast precursors induce osteoclast differentiation in the absence of RANKL.[18]

Conclusion

Nicotine inhibits the osseointegration of dental implants by increasing nAChR, NFATc1, osteoclast numbers, and decreasing osteoblast numbers.

Conflict of Interest

The authors declare that they are unaware of competing financial interests or personal relationships that may have influenced the work described in this document.

Acknowledgments

We would like to thank Prof. Dr. drg. Mohamad Rubianto, MS, Sp.Perio(K) and Prof. Dr. Kuntaman, dr. MS, SpMK(K) for the contribution to this manuscript.

• References

• 1 Shenava S, Singh P, Sharath Babu C, Kumar V, Jyoti B, Sharma S. Co-relation between smoking and bone healing around dental implants: a clinical study. J Int Oral Health 2016; 8: 1-3
• 2 Arora A, Reddy MM, Mhatre S, Bajaj A, Gopinath PV, Arvind P. Comparative evaluation of effect of smoking on survival of dental implant. J Int Oral Health 2017; 9: 24-27
• 3 Schwartz-Arad D, Samet N, Samet N, Mamlider A. Smoking and complications of endosseous dental implants. J Periodontol 2002; 73 (02) 153-157
• 4 Heitz-Mayfield LJA, Huynh-Ba G. History of treated periodontitis and smoking as risks for implant therapy. Int J Oral Maxillofac Implants 2009; 24 (Suppl): 39-68
• 5 Cavalcanti R, Oreglia F, Manfredonia MF, Gianserra R, Esposito M. The influence of smoking on the survival of dental implants: a 5-year pragmatic multicentre retrospective cohort study of 1727 patients. Eur J Oral Implantology 2011; 4 (01) 39-45
• 6 Chrcanovic BR, Albrektsson T, Wennerberg A. Smoking and dental implants: a systematic review and meta-analysis. J Dent 2015; 43 (05) 487-498
• 7 Tymkiw KD, Thunell DH, Johnson GK. et al. Influence of smoking on gingival crevicular fluid cytokines in severe chronic periodontitis. J Clin Periodontol 2011; 38 (03) 219-228
• 8 García B, Penarrocha M, Martí E, Gay-Escodad C, von Arx T. Pain and swelling after periapical surgery related to oral hygiene and smoking. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007; 104 (02) 271-276
• 9 Larrazábal C, García B, Peñarrocha M, Peñarrocha M. Influence of oral hygiene and smoking on pain and swelling after surgical extraction of impacted mandibular third molars. J Oral Maxillofac Surg 2010; 68 (01) 43-46
• 10 Shibli JA, Piattelli A, Iezzi G. et al. Effect of smoking on early bone healing around oxidized surfaces: a prospective, controlled study in human jaws. J Periodontol 2010; 81 (04) 575-583
• 11 Bezerra Ferreira JD, Rodrigues JA, Piattelli A, Iezzi G, Gehrke SA, Shibli JA. The effect of cigarette smoking on early osseointegration of dental implants: a prospective controlled study. Clin Oral Implants Res 2016; 27 (09) 1123-1128
• 12 Chrcanovic BR, Kisch J, Albrektsson T, Wennerberg A. Factors influencing early dental implant failures. J Dent Res 2016; 95 (09) 995-1002
• 13 Nazeer J, Singh R, Suri P. et al. Evaluation of marginal bone loss around dental implants in cigarette smokers and nonsmokers. A comparative study. J Family Med Prim Care 2020; 9 (02) 729-734
• 14 Takamiya AS, Goiato MC, Gennari Filho H. Effect of smoking on the survival of dental implants. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2014; 158 (04) 650-653
• 15 Ghayor C, Correro RM, Lange K, Karfeld-Sulzer LS, Grätz KW, Weber FE. Inhibition of osteoclast differentiation and bone resorption by N-methylpyrrolidone. J Biol Chem 2011; 286 (27) 24458-24466
• 16 Choi J, Choi SY, Lee SY. et al. Caffeine enhances osteoclast differentiation and maturation through p38 MAP kinase/Mitf and DC-STAMP/CtsK and TRAP pathway. Cell Signal 2013; 25 (05) 1222-1227
• 17 Kwak HB, Yang D, Ha H. et al. Tanshinone IIA inhibits osteoclast differentiation through down-regulation of c-Fos and NFATc1. Exp Mol Med 2006; 38 (03) 256-264
• 18 Takayanagi H, Kim S, Koga T. et al. Induction and activation of the transcription factor NFATc1 (NFAT2) integrate RANKL signaling in terminal differentiation of osteoclasts. Dev Cell 2002; 3 (06) 889-901
• 19 En-Nosse M, Hartmann S, Trinkaus K. et al. Expression of non-neuronal cholinergic system in osteoblast-like cells and its involvement in osteogenesis. Cell Tissue Res 2009; 338 (02) 203-215
• 20 Liang D, Wang KJ, Tang ZQ. et al. Effects of nicotine on the metabolism and gene expression profile of Sprague‑Dawley rat primary osteoblasts. Mol Med Rep 2018; 17 (06) 8269-8281
• 21 Søballe K. Hydroxyapatite ceramic coating for bone implant fixation. Mechanical and histological studies in dogs. Acta Orthop Scand Suppl 1993; 255: 1-58
• 22 Shroff Y, Shah M, Vyas M, Pandya R. Smoking and implant failure: an evidence based review. IOSR J Dent Med Sci 2018; 17: 60-64
• 23 Pereira ML, Carvalho JC, Peres F, Fernandes MH. Effect of nicotine in matrix mineralization by human bone marrow and Saos-2 cells cultured on the surface of plasma-sprayed titanium implants. J Biomed Mater Res A 2009; 88 (01) 84-93
• 24 Kim BS, Kim SJ, Kim HJ. et al. Effects of nicotine on proliferation and osteoblast differentiation in human alveolar bone marrow-derived mesenchymal stem cells. Life Sci 2012; 90 (3−4): 109-115
• 25 Nitzan D, Mamlider A, Levin L, Schwartz-Arad D. Impact of smoking on marginal bone loss. Int J Oral Maxillofac Implants 2005; 20 (04) 605-609
• 26 Garg A. Pathophysiology of tobacco use and wound healing. Dent Implantol Update 2010; 21 (01) 1-4
• 27 Henemyre CL, Scales DK, Hokett SD. et al. Nicotine stimulates osteoclast resorption in a porcine marrow cell model. J Periodontol 2003; 74 (10) 1440-1446
• 28 Adler ID, Attia SM. Nicotine is not clastogenic at doses of 1 or 2 mg/kg body weight given orally to male mice. Mutat Res 2003; 542 (1-2): 139-142
• 29 Tanaka H, Tanabe N, Shoji M. et al. Nicotine and lipopolysaccharide stimulate the formation of osteoclast-like cells by increasing macrophage colony-stimulating factor and prostaglandin E2 production by osteoblasts. Life Sci 2006; 78 (15) 1733-1740
• 30 Kliemann K, Kneffel M, Bergen I. et al. Quantitative analyses of bone composition in acetylcholine receptor M3R and alpha7 knockout mice. Life Sci 2012; 91 (21−22): 997-1002
• 31 Tanaka H, Tanabe N, Kawato T. et al. Nicotine affects bone resorption and suppresses the expression of cathepsin K, MMP−9 and vacuolar-type H(+)-ATPase d2 and actin organization in osteoclasts. PLoS One 2013; 8 (03) e59402
• 32 Lips KS, Yanko Ö, Kneffel M. et al. Small changes in bone structure of female α7 nicotinic acetylcholine receptor knockout mice. BMC Musculoskelet Disord 2015; 16 (01) 5
• 33 Kim JH, Kim N. Regulation of NFATc1 in osteoclast differentiation. J Bone Metab 2014; 21 (04) 233-241
• 34 Wu LZ, Duan DM, Liu YF, Ge X, Zhou ZF, Wang XJ. Nicotine favors osteoclastogenesis in human periodontal ligament cells co-cultured with CD4(+) T cells by upregulating IL−1β. Int J Mol Med 2013; 31 (04) 938-942
• 35 Rothem DE, Rothem L, Dahan A, Eliakim R, Soudry M. Nicotinic modulation of gene expression in osteoblast cells, MG−63. Bone 2011; 48 (04) 903-909
• 36 Asagiri M, Takayanagi H. The molecular understanding of osteoclast differentiation. Bone 2007; 40 (02) 251-264
• 37 Wang L, Chen K, He J. et al. Cytochalasin Z11 inhibits RANKL-induced osteoclastogenesis via suppressing NFATc1 activation. RSC Advances 2019; 9 (66) 38438-38446

Publikationsverlauf

Artikel online veröffentlicht:
27. Dezember 2022