Clinicoradiographic Evaluation of Long-term Efficacy and Risk Factors Associated with Dental Implants used for Full Mouth Rehabilitation.

Background: Despite various complications and failure factors, newer implants are designed that allow placement in sub-optimal conditions to allow the operator to place implants at sites with low bone quality. These newer designs also allow improved stability with higher survival rates in the short term. Aims: The present study was undertaken to evaluate long-term efficacy and risk factors associated with dental implant placement for full mouth rehabilitation. Materials and
Methods: In 24 subjects, 438 implants were placed. The data collected were surgical and were retrospectively analyzed. The data collected included medical history, local, patient satisfaction, marginal bone loss, and systemic risk factors affecting implant survival. Outcome variables assessed were peri-implantitis, implant success, and survival at the follow-up visit. The data were expressed in terms of percentage and number, and the results were derived.
Results: Peri-implantitis was seen in 31.05% (n = 136) of implants. 76.02% (n = 333) of implants were considered successful at recall. Concerning survival, compromised and satisfactory survival was shown by 10.04% (n = 44) and 2.96% (n = 13) of implants, respectively. 10.95% (n = 48) of implants were considered as failures.
Conclusion: The present study concludes that good, long-term survival rates are associated with full mouth rehabilitation using dental implants. Copyright:

INTRODUCTION

Dental implants have become the most preferred options for teeth replacement in recent times. With advances in surgical techniques and implant surface characteristics, approximately 90% success rates of 10 years are reported with dental implants used for the replacement of missing teeth. With promising success rates and long-term survival, dental implants are the treatment of choice by both patients and dentists. However, various local and systemic complications associated with dental implants impose a challenge on using dental implants.[1]

These complications can be local or systemic, and early or late. These complications, if not managed, can lead to implant failure. Early complications include pain, infection, and bleeding from the implant site. Implant failure can be seen due to failed osseointegration, breakage, and peri-implant infection. Relative implant contraindications are endocarditis, epilepsy, diabetes, and smoking, whereas absolute contraindications are myocardial infarction, bleeding history, immunosuppression, heart transplant, drug abuse, malignancy, and/or cerebrovascular accident.[2]

Implant failure is dependent on various factors which are either surgery-related, site-related, implant-fixture-related, prosthesis-related, or host-related. Osseointegration is also affected by implant design, implant surface, surgery technique, site, and implant loading. Despite various complications and failure factors, newer implants are designed that allow placement in suboptimal conditions to allow the operator to place implants at sites with low bone quality. These newer designs also allow improved stability with higher survival rates in the short term.[1]

Another major concern associated with dental implants is an inflammatory disease of soft and hard tissues surrounding dental implants, termed peri-implantitis. Peri-implantitis progresses at faster rates compared to periodontitis. Peri-implantitis can lead to implant failure. Factors predisposing the patient to peri-implantitis are lack of oral hygiene, improper plaque control, and history of periodontitis. Owing to the great contribution of these factors in altering efficacy and affecting implant success, these factors are less studied in the literature.[3]

Data concerning efficacy and risk factors associated with implant failure are scarce in the literature, especially in cases with full mouth rehabilitation using dental implants. This affects and limits the use of dental implants in completely edentulous subjects. Hence, the present study was undertaken to evaluate long-term efficacy and risk factors associated with dental implant placement for full mouth rehabilitation.

MATERIALS AND METHODS

The present retrospective clinical study was undertaken to evaluate long-term efficacy and risk factors associated with dental implant placement for full mouth rehabilitation. The study was carried out after obtaining clearance from the concerned ethical committee and after obtaining consent from the participants. The study included a total of 24 subjects from both genders. The study population comprised of subjects visiting the outpatient department for the replacement of missing teeth.

The inclusion criteria for the study were subjects who were completely edentulous, subjects with radiation history in head and neck region for the past two years, no history of bisphosphonate drug intake, mentally fit subjects, subjects with no medical history affecting implant placement, and subjects who were willing to participate in the study. The exclusion criteria were subjects not meeting inclusion criteria and subjects not willing to participate in the study. The data of subjects meeting inclusion criteria were retrieved from the department records and the subjects were recalled for clinical follow-up.

A total of 32 subjects met the inclusion criteria; however, 25% (n = 8) of subjects were either not reachable, were deceased, or were not willing for follow-up, and hence, were excluded from the study. After explaining the detailed study design, informed consent was taken verbally as well as in written format. After final inclusion, radiographs from insertion day were collected from all the subjects, followed by current bone level evaluation. The data collected were surgical and were retrospectively analyzed.

All data were collected in a single visit and by a single examiner who was an expertise in the field. The data collected were medical history, local and systemic risk factors affecting implant survival. Implant satisfaction was rated on a scale of 0–10 from unsatisfied to very satisfied. Marginal bone loss was assessed radiographically, comparing the difference of initial radiograph to latest radiograph including OPG, CBCT, IOPA (whichever available) at the mesial and distal aspect of implants [Figure 1].

Figure 1

Radiographic and clinical presentation of full mouth rehabilitation by dental implants in upper and lower jaw

Outcome variables assessed were peri-implantitis, implant success, and survival at the follow-up visit. Health scale for dental implants[4] was used for assessing implant success. Peri-implantitis was evaluated from bleeding on probing, radiographic bone loss of >0.5 mm, and/or exudation.[5] Peri-implant mucositis used similar parameters as peri-implantitis with bone loss of <0.5 mm. The study used recent radiographs not older than one year.

The collected data were subjected to statistical evaluation for result formulation. The data were expressed in terms of percentage and number, and the results obtained.

RESULTS

The present retrospective clinical study was undertaken to evaluate long-term efficacy and risk factors associated with dental implant placement for full mouth rehabilitation. The study included a total of 24 subjects from both genders, and a total of 438 dental implants were placed. It was seen that 25% (n = 6) of subjects were daily alcoholics, whereas, 33.3% (n = 8) consumed alcohol occasionally. There were 20.83% (n = 5) smokers in the study. 4.16% of subjects were taking bisphosphonates intravenously, whereas 8.33% (n = 2) were taking oral bisphosphonates. Bruxism was present in 41.66% (n = 10) of study subjects. 12.5% (n = 3) of subjects had poor oral hygiene. Periodontitis was seen in 41.66% (n = 10) of subjects and was absent in 58.33% (n = 14) of study subjects. Oral prophylaxis was taken never, once a year/less, and more than once a year by 4.16% (n = 1), 79.16% (n = 19), and 16.66% (n = 4) of study subjects respectively [Table 1].

Table 1

Local and systemic risk factors in the study subjects

Risk Factors	Subgroup	%	n
Alcohol intake	Daily	25	6
	Occasionally	33.3	8
Smoking	Present	20.83	5
	Absent	79.16	19
Bisphosphonate intake	Intravenous	4.16	1
	Oral	8.33	2
Immunosuppressants intake	Present	8.33	2
	Absent	91.66	22
Bruxism	Present	41.66	10
	Absent	58.33	14
Poor oral hygiene	Periodontitis	12.5	3
	Present	41.66	10
	Absent	58.33	14
Oral prophylaxis	Never	4.16	1
	Once a year/less	79.16	19
	More than once a year	16.66	4

The mean recall period for the study was 3.64 ± 1.86 years. Upon assessing clinicoradiographic parameters, it was seen that plaque at implant surface was seen in 34.93% (n = 153) of implants, bleeding on probing in 65.98% (n = 289), spontaneous bleeding in 2.05% (n = 9), and exudation in 0.91% (n = 4). Pocket depth of >3 mm and recession were seen in 15.98% (n = 70) and 21% (n = 92) implants respectively. Concerning prosthesis, crowns were placed for 77.85% (n = 341) implants and implant-supported fixed dentures for 22.14% (n = 97) of implants. Prostheses were retained using cementation in 81.96% (n = 359) of implants and were screw retained for 18.03% (n = 79). 91.66% (n = 22) of subjects were completely satisfied with full mouth rehabilitation using implants. For radiographic parameters, <1 mm bone loss was seen in 76.94% (n = 337) of implant sites and >1 mm at 23.05% (n = 101) of implant sites [Table 2].

Table 2

Clinicoradiographic parameters in the study subjects

Clinicoradiographic factors	Subgroups	%	n
Gingivitis	Plaque	34.93	153
	Bleeding on probing	65.98	289
	Spontaneous bleeding	2.05	9
	Exudation	0.91	4
	Pocket depth (>3 mm)	15.98	70
	Recession	21	92
Prosthesis	Crowns	77.85	341
	Implant-supported fixed dentures	22.14	97
Prosthesis retention	Cementation	81.96	359
	Screw-retained	18.03	79
Patient satisfaction	Patient Satisfaction	91.66	22
Radiographic bone loss	<1 mm	76.94	337
	>1 mm	23.05	101

Upon assessing the implant-related outcomes, it was seen that peri-implantitis was seen in 31.05% (n = 136) of implants. 76.02% (n = 333) of implants were considered successful at recall. Concerning survival, compromised, and satisfactory survival was shown by 10.04% (n = 44), and 2.96% (n = 13) implants. 10.95% (n = 48) of implants were considered as failures [Table 3]. All the outcomes were assessed following the health scale for dental implants.

Table 3

Implant-related outcomes at recall in study subjects

Outcomes	%	n
Peri-implantitis	31.05	136
Implant success	76.02	333
Compromised survival	10.04	44
Satisfactory survival	2.96	13
Failure	10.95	48

DISCUSSION

The study included a total of 24 subjects from both genders, and a total of 438 dental implants were placed. The local and systemic risk factors were evaluated in the study subjects at the recall visit. The results are depicted in Table 1. It was seen that 25% (n = 6) of subjects were daily alcoholics, whereas 33.3% (n = 8) of subjects took alcohol occasionally. There were 20.83% (n = 5) smokers in the study. 4.16% of subjects were taking bisphosphonates intravenously, whereas 8.33% (n = 2) of subjects were taking oral bisphosphonates. Bruxism was present in 41.66% (n = 10) of study subjects. 12.5% (n = 3) of subjects had poor oral hygiene. Periodontitis was seen in 41.66% (n = 10) of subjects and was absent in 58.33% (n = 14). Oral prophylaxis was taken never, once a year/less, and more than once a year by 4.16% (n = 1), 79.16% (n = 19), and 16.66% (n = 4) study subjects, respectively. These risk factors were similar to what was considered in the studies by Wilson Jr et al.[6] in 2009 and Linkevicius T et al.[7] in 2013 where smoking and uncontrolled diabetes were the main risk factors depicting implant success.

The mean recall period for the study was 3.64 ± 1.86 years. Upon assessing clinicoradiographic parameters, it was seen that plaque at implant surface was seen in 34.93% (n = 153) of implants, bleeding on probing in 65.98% (n = 289), spontaneous bleeding in 2.05% (n = 9), and exudation in 0.91% (n = 4). Pocket depth of >3 mm and recession were seen in 15.98% (n = 70) and 21% (n = 92) of implants respectively. Concerning prosthesis, crowns were placed for 77.85% (n = 341) of implants and implant-supported fixed dentures for 22.14% (n = 97). Prostheses were retained using cementation in 81.96% (n = 359) of implants and were screw-retained for 18.03% (n = 79). 91.66% (n = 22) of subjects were completely satisfied with full mouth rehabilitation using implants. For radiographic parameters, <1 mm bone loss was seen at 76.94% (n = 337) of implant sites and >1 mm at 23.05% (n = 101) implant sites. These results were consistent with the results of Ho DSW et al.[8] in 2013 and Derks J et al.[9] in 2016 where comparable clinicoradiographic factors were depicted by the authors.

Upon assessing the implant-related outcomes, it was seen that peri-implantitis was seen in 31.05% (n = 136) of implants. Implants were considered successful for 76.02% (n = 333) of implants. Concerning survival, compromised and satisfactory survival was shown by 10.04% (n = 44), and 2.96% (n = 13) of implants. 10.95% (n = 48) were considered as failures. All the outcomes were assessed following the health scale for dental implants. These findings were in agreement with the studies by Doornewaard, R et al.[10] in 2018, and Derks J et al.[11] in 2015, where implant survival and success-related outcomes were similar to the present study.

CONCLUSION

Within its limitations, the present study concludes that good long-term survival rates are associated with full mouth rehabilitation using dental implants. Implant failure is linked with various local and systemic factors, which, when controlled, can improve survival. Special emphasis should be done on periodontitis and peri-implantitis by regular follow-up. However, the study has a few limitations including smaller sample size, retrospective design, geographical area biases, recall bias, and single-institution nature. Hence, more longitudinal and prospective studies with a larger sample size, and longer monitoring period are needed to reach a definitive conclusion.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.