Amount of bone loss after maxillary dental implant loading in smoker and non-smoker patients

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1 Amount of bone loss after maxillary dental implant loading in smoker and non-smoker patients Taha Y. Hamad, B.D.S., H.D.D., M.Sc. (1) Background: Excessive crestal bone loss after dental implant occurs due to many factors among which, is smoking. This study was conducted to evaluate the effect and role of smoking in breakdown of bone around dental implant and the possibility to be a factor of its failure. Method: Forty implants had been inserted in anterior and bicuspid region of upper arch of 40 systemically healthy male subjects, 20 were smokers and the other 20 subjects were non smokers. After loading the prosthesis, all subjects were followed by clinical (checking for any mobility or gingival change) and radiographic examination for two successive 6 months periods (the overall follow up period was 1 year). Mesial and distal bone levels were measured by digitized x ray each six months in both smokers and non smokers. All measurements were recorded for each patient and a comparison of marginal bone level was done. Results: A marked excessive marginal bone loss was found at mesial side of smokers, mean (1.18± 0.033) mm after 6 months of loading and mean of (1.52 ± 0.052) mm after 1 year, while in non smoker group, the mean of mesial bone loss after 6 months was (0.85 ± 0.026) mm and (1.12 ± 0.031) mm after 1 year. The mean distal bone loss in smokers at the two periods was (1.23 ± 0.04) mm and (1.59 ± 0.046) mm, while in non smokers, the mean distal bone loss was (0.87 ± 0.023) mm and (1.1 ± 0.029) mm respectively. Differences in all measurements were significant P < Conclusion: Smoking could be a factor results in future implant failure Key words: maxillary dental implant, smoking, bone loss. (J Bagh Coll Dentistry 2012;24(1):76-81). INTRODUCTION Smoking had been proved to affect oral health ranging from bad breath, periodontal diseases to delayed wound healing after oral surgery (1). A previous study concluded that smoking is a real risk factor that may affect survival of sinus floor augmentation for dental implant (2), but few studies had been carried out to find the effect of smoking on bone areas rather than sinus (3, 4). Smoking had been reported to result in gingival disease due to plaque and tartar build up and interferes with the normal cellular function of periodontal tissue (5). Other study stated that smokers are 4 times more likely to develop advanced periodontitis which is the leading cause of tooth loss in adults (6). Smoking not only creates dental health issues but worsens already existing dental conditions. Mavropoulos et al (7) reported a direct correlation between gingival disease and number of cigarettes smoked per day and stated that people who smoke less than 10 cigarettes a day were three times more likely to suffer from periodontal disease than non-smokers, where as people who smoked more than 30 cigarettes a day were 6 times more likely for the same disease. Smokers show higher score in bleeding index with greater peri-implant pocket depth and higher bone resorption around the implant (8). A study had pointed out the reduced ability of hard and soft oral tissue to heal and regenerate after surgery especially after dental implant in smoker patients due to reduction of (1)Assist lecturer/ College of Dentistry/ Mustansirya University Oral and Maxillofacial Surgery and Periodontology76 immunity and nutrients as a result of smoking which renders the smoker patient more susceptible to peri-implantitis and subsequent marginal bone loss around the implant (9).This study was conducted to compare marginal bone loss around implant between smokers and non smokers for 1 year after loading. METHOD All operations were done without using bone chips (without enhancement of bone formation) in private clinic from November September 2011, all patients were systemically healthy and not taking any medication, they were 20 non smoker males with ages range from years (mean SD 33.6 ± 6.8), they received 20 dental implants in upper anterior and bicuspid regions, and 20 smoker males with ages range from years (mean SD 33.1 ± 6.4), the average number of cigarettes smoked by each one of this group per day was cigarettes for 5-10 years, they also received 20 implants in the upper anterior and bicuspid region (i e almost similar ages and implant regions) as shown in table (1). Scaling and polishing was done for each patient prior to procedure and the patient was instructed to rinse with chlorhexidine (0.12%) three to four times minutes before operation, and after anaesthesia, a midline incision was made at crestal bone covering tissue and three sided flap was elevated, drilling was made and an implant (type Euroteknika natura type platinium grade 4) was inserted into 10 and 12 mm depth of bone according to anatomical guides for each patient, diameters of implants ranged from 3-4 mm

2 according to bone width, all implants were introduced with perfect primary retention, the platiform of all implants was within the crestal bone level. All implants were closed with healing covers ranging from 1-2 mm height according to gingival thickness to prepare gingival forma. Mesial and distal sides were sutured with 0.2 mm silks. all patient were given Ceftriaxone 6 vials 1 gm 12 hourly, Dexamethasone one ampoule (to reduce swelling as anti-inflammatory), (0.12%) chlorhexidine mouth rinse twice daily and Voltaren tab 100 mg three times a day for three days, all sutures were removed after 8-10 days, then the patient was given appointment for further 50 days, impression coping was fixed for each implant, impressions were taken, then copings were unscrewed from implants and covers were replaced again, analogues were screwed to impression coping and the impression was filled with stone, the coping were replaced by abutments and sent for ceramic prosthesis which lasts for about 2 weeks, then inserted into patient mouth, so the period from inserting the implant to final loading of ceramic crown lasts about 70 days (delayed immediate method) (10). Final crowns were kept about 1 mm below occlusion in order not to be exposed to direct occlusal forces until reasonable osseointegration had been occurred. The level of mesial and distal bone around implants for all patients were measured (to determine the amount of bone loss) by digitized x ray (11) taken for all implants six months and 1 year after loading respectively. The sensor of the digital radiography unit was inserted into the patient s mouth, this sensor is connected via USB to the computer of the unit, after exposure, the image appeared on the screen of the computer, and by using digital tools, focusing on the proximal area was achieved, a line was drawn at the level of platiform of the implant (which was placed within the level of the crestal bone during surgery), another line was drawn at the level of proximal bone and the difference between the two lines was calculated by using the digital tools software. RESULTS A multiple linear regression model was used to study the net and independent effect of smoking after adjusting for possible confounding effect of age and tooth type on the amount of crestal bone loss after 6 months and 1 year of loading. All the 4 models were statistically significant and able to explain between 53% and 69% of observed variation in the response (dependent) variable. Both confounding variables (tooth type and age) Oral and Maxillofacial Surgery and Periodontology77 had no important or statistically significant effect on amount of crestal bone loss after adjusting for smoking habit. As shown in table (2), there was higher bone loss at mesial and distal sides of implants in smokers group. The mean mesial bone loss in smokers was (1.18± 0.033) mm after 6 months of loading ranging from mm and mean of (1.52 ± 0.052) mm after 1 year ranging from mm, while in non smoker group, the mean of mesial bone loss after 6 months was (0.85 ± 0.026) mm ranging from mm and (1.12 ± 0.031) mm after 1 year ranging from mm. The mean distal bone loss in smokers at the two periods was (1.23 ± 0.04) mm ranging from mm and (1.59 ± 0.046) mm ranging from mm, while in non smokers, the mean distal bone loss was (0.87 ± 0.023) mm ranging from mm and (1.1 ± 0.029) mm ranging from mm respectively. Being smoker was associated with a statistically significant increase in crestal bone loss by a mean of 0.33 mm (table 3) to 0.36 mm (table 4) respectively after 6 months of loading on mesial and distal side, after adjusting for the effect of age and tooth position. On the other hand after 1 year of loading a positive smoking habit was associated with a statistically significant increase in crestal bone loss by a mean of 0.4 mm (table 5) to 0.49 mm (table 6) respectively on mesial and distal side, after adjusting for the effect of age and tooth position. Statistical analysis revealed that there was significant difference P <0.001 in mesial and distal bone loss between smokers and non smokers after 6 months and 1 year of loading, but there was no significant difference in variables represented by age and implant site between subjects in both groups (as shown in tables 4, 5, 6) except in mesial bone loss after 6 months, there was significant difference P= between premolar and anterior implants (as shown in tables 3). Figure (1) showed the mean difference in distal and mesial bone loss between the two groups with inter quartile field which represents the distribution of magnitude of bone loss among subjects belong to the group after 6 months and 1 year. After 6 months, the mean of distal bone loss in non smokers was 0.86 mm, circles illustrate the least amount of bone loss (0.65 mm) and the most bone loss (1 mm), while the red vertical line illustrates the inter quartile distribution of bone loss among subjects of this group, in smokers, the mean distal bone loss was 1.23 mm, the least was 0.90 mm and the most was 1.5 mm. The adjacent two columns illustrate the same findings after 1

3 year of loading. In respect to mesial bone loss, the same idea was explained in figure (2). Figure 3 showed upper left central implant for a 37 years old non smoker subject with mesial bone loss of 0.75 mm and distal bone loss of 0.80 mm from platiform level after 1 year of loading, while the bone loss in upper left premolar implant for a 36 years old smoker subject was 1.4 mm mesially and 0.85mm distally from platiform level after 1 year. Table 1: Frequency distribution of the cases (smokers) and controls (non-smokers) by age and type of teeth Non-smoker Smoker N % N % Age group (years) < Total Range (22-45) (24-46) Mean SD N Type of teeth Anterior (1-2) Premolars (4-5) Total Table 2: The case-control difference in mean crestal bone loss (mm) after 6 months and 1 year after loading Crestal bone loss (mm)-mesial side Crestal bone loss (mm)-distal side After 6 months After 1 year After 6 months After 1 year Smoking habit (n=20) (n=20) (n=20) (n=20) Controls (Non-smokers) Range (0.6-1) ( ) (0.65-1) ( ) Mean ± SE 0.85 ± ± ± ± Cases (Smokers) Range ( ) (1-1.9) ( ) ( ) Mean ± SE 1.18 ± ± ± ± P (t-test) <0.001 <0.001 <0.001 <0.001 T Df Table 3: Multiple linear regression with crestal bone loss (mm)-mesial side-after 6 months as the Crestal bone loss (mm)-mesial side-after 6 Unstandardized partial months Premolars compared to Anterior teeth Smokers compared to non-smokers 0.33 < Age in years [NS] P (Model) <0.001 R 2 = 0.66 Oral and Maxillofacial Surgery and Periodontology78

4 1.8 Means (error bars: 95% CI for mean) Crestal bone loss (mm)-distal side Smoking habit 0 1 Figure 1: Dot diagram with error bars showing the difference in mean (with its 95% confidence interval) of crestal bone loss (mm)-distal side between smokers and non-smokers 2.0 Means (error bars: 95% CI for mean) Crestal bone loss (mm)-mesial side Smoking habit months 1 year Figure 2: Dot diagram with error bars showing the difference in mean (with its 95% confidence interval) of crestal bone loss (mm)-mesial side between smokers and non-smokers Table 4: Multiple linear regression with crestal bone loss (mm)-distal side-after 6 months as the Crestal bone loss (mm)-distal side-after 6 Unstandardized partial months Premolars compared to Anterior teeth [NS] Smokers compared to non-smokers 0.36 < Age in years [NS] P (Model) <0.001 R 2 = 0.64 Oral and Maxillofacial Surgery and Periodontology79

5 Table 5: Multiple linear regression with crestal bone loss (mm)-mesial side-after 1 year as the Crestal bone loss (mm)-mesial side-after 1 Unstandardized partial year Premolars compared to Anterior teeth [NS] Smokers compared to non-smokers 0.40 < Age in years [NS] P (Model) <0.001 R 2 = 0.53 Table 6: Multiple linear regression with crestal bone loss (mm)-distal side-after 1 year as the Crestal bone loss (mm)-distal side-after 1 Unstandardized partial year Premolars compared to Anterior teeth [NS] Smokers compared to non-smokers 0.49 < Age in years [NS] P (Model) <0.001 R 2 = 0.69 A (smoker) B A (non smoker) B Figure 3: Shows amount of mesial and distal bone loss 6 months after loading (B) and 1 year after loading (A) in a smoker and non smoker patient DISCUSSION Tobacco smoke has more than just nicotine hidden within its vapors; it contains carbon monoxide, tar and hydrogen cyanide (12). The healing process involves growth of new bone and gingival tissue to integrate with the implant. Smoking is harmful to all oral tissues, especially when implants are present, it reduces proliferation of RBCs, fibroblasts and macrophages (13), also it promotes the release of epinephrine and norepinephrine resulting in vasoconstriction and decreased tissue perfusion (14). Carbone monoxide reduces the oxygen carrying capacity of blood (15), thus, resulting in ischemia which is the most important pathophysiological factor in impaired healing of bone and soft tissue and reduces their ability to resist infection (peri-implantitis) which is the main cause of breakdown of bone (16). This may explain the excessive marginal bone loss around implants in smokers than in non smokers. A study followed 66 patients over 5 years, who received 165 implants, found that 15.8% of implants failed in smokers, versus 1.4% of implants in non-smokers (17). Another retrospective study of 5 years follow up showed 14.6% implant failure in smokers and only 1.2% failure in non smokers (18). The formation of deep mucosal pockets with inflammation of the periimplant mucosa around dental implants is called peri-implantitis. Smokers treated with dental implants have a greater risk of developing periimplantitis. This condition can lead to increased resorption of peri-implant bone and can lead to future implant failure. The procedure of implants insertion and loading for 40 subjects enrolled in this study lasted about 10 months, so the follow up of those subjects was only 1 year after implant loading (during which, there was not any clinical sign of implant failure for any patient) and this period is considered too short for assessing long standing survival of implants, accordingly, this study could not be compared with another studies Oral and Maxillofacial Surgery and Periodontology80

6 which had been characterized by larger number of implants and long period of follow up (5 years and more). That is why, it is recommended to increase the sample and the period of follow up so that to be in line with other studies to achieve fair comparison between results. As a general speaking, we can say that this study gave us a hint about one of the main factors which may result in marginal bone loss around implants which may threaten its survival. REFERENCES 1. Johnson GK, Slach NA. Impact of tobacco use on periodontal status. J Dent Educ 2001; 65 (4): Kan JY, Runrcharassaeng K, Kim J, Lozada JL, Goodcare CJ. Factors affecting the survival of implants placed in grafted maxillary sinuses: A clinical report. J Prosthet Dent 2002; 87: Schwartz- Arad D, Samet N, Mamlider A. Smoking and complications of endoosseous dental implant. J Periodontol 2002;73: Peter A Reichart, Abhijit Kale, Milind Kulkarni, Brigitte Wegner, Ingeborg Küchler. Smoking interferes with the prognosis of dental implant treatment: a systematic review and meta-analysis. J Clin Periodontol 2007; Jun: 34 (6): Haffajee AD, Socransky SS. Relationship of cigarette smoking to the subgingival microbiota. J Clin Periodontol 2001; 28: Novak MJ, Novak KF. Newman, Takei and Carranza, Carranza s- Clinical Periodontology. 9 th ed Smoking and periodontal disease; p Mavropoulos A, Aars H, Brodin P. Hyperaemic response to cigarette smoking in healthy gingiva. J Clin Periodontol 2003, 30: Lindquist LW, Carlsson GE, Jemt T. Association between marginal bone loss around osseointegrated mandibular implants and smoking habit: A 10-year follow-up. J Dent Res 1997; 76: De Bruyn H, Collaret B. The effect of smoking on early implant failure. Clin Oral Implants Res 1994; 3: Degidi M, Piatelli A. 7-year follow-up of 93 immediately loaded titanium dental implants, J Oral Implantol 2005;31: Wolf B, von Bethlenfalvy E, Hassfeld S, Staehle HJ, Eickholz P. Reliability of assessing interproximal bone loss by digital radiography: intrabony defects. J Clin Periodontol 2001;28(9): Kan JYK, Rungcharassaeng K, Lozada JL, Goodacre CJ. Effects of smoking on implant success in grafted maxillary sinuses. J Prosthet Dent 1999; 82: Silverstein P. Smoking and wound healing. Am J Med 1992; 93: Christen AG. The clinical effects of tobacco on oral tissue. J Am Dent Assoc 1970; 81: Jones JK, Triplett RG. The relationship of cigarette smoking to impaired intraoral wound healing: A review of evidence and implications for patient care. J Oral Maxillofac Surg 1992; 50: Bain CA, Weng D, Meltzer A, Kohles SS, Stach RM, A meta-analysis evaluating the risk for implant failure in patients who smoke. Compend Contin Educ Dent 2002; 23:695, 702, Wallace RH. The relation between cigarette smoking and dental implant failure. Eur J Prosth Restor Dent 2000;8: Arturo Sánchez-Pérez MJ, Moya-Villaescusa and RG Caffesse. Tobacco as a Risk Factor for Survival of Dental Implants. J Periodontol 2007; 78(2): Oral and Maxillofacial Surgery and Periodontology81