Complications of Dental Implants: Identification, Frequency and Associated Risk Factors

1
Complications of Dental Implants Identification,
Frequency and Associated Risk Factors

• NE McDermott, BS, S-K Chuang, DMD, MD,
• VA Vehemente, BS, S Daher, DMD,
• A Muftu, DDS, MS, TB Dodson, DMD, MPH
• Harvard School of Dental Medicine
• Massachusetts General Hospital
• Boston University Goldman School of Dental
  Medicine
• Tufts University School of Dental Medicine

2

• Background and Significance

• Dental implants are a widely accepted treatment
  modality.
• Questions exist regarding complications
  associated with dental implants.
• Systematic reports of implant complications and
  associated risk factors are limited.

3
Specific Aims

• Specific Aim 1 To identify complications
  associated with dental implants.
• Specific Aim 2 To estimate the frequency of
  implant complications.
• Specific Aim 3 To identify risk factors
  associated with implant complications.

4
Hypothesis

• We hypothesize that we will identify risk factors
  associated with implant complications that may be
  modified by the clinician to enhance patient
  outcome.

5

• Materials and Methods

• Study Design Retrospective cohort
• Sample Patients having gt one Bicon implant
  placed at the Implant Dentistry Centre (IDC),
  Faulkner Hospital (Boston, MA) between 1992 and
  2000
• Randomly selected one implant per patient for
  study inclusion

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Study Variables

• Predictor Variables (Risk Factors)
• Demographic
• -gender
• -age
• Medical
• -ASA status
• -tobacco use

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• Anatomic
• implant location (maxilla vs. mandible, anterior
  vs. posterior)
• bone quality (1-4)
• implant proximity to teeth or implants
• Implant Specific
• implant diameter and length
• well size
• implant coating
• implant staging
• abutment diameter and angulation

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• Prosthetic
• removable (overdenture) or fixed (crown/ bridge)
• Reconstructive
• use of procedures/materials to enhance recipient
  site
• Other
• -perioperative antibiotic use

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Study Variables (Contd)

• Outcome Variable
• presence or absence of complications
• Complications grouped into three categories
• inflammatory
• prosthetic
• operative

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• Inflammatory Complications
• -mobility
• -pain
• -infectious process
• -peri-implantitis
• -impaired wound healing
• -gingival recession

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• Prosthetic Complications
• abutment fracture/loosening
• O-ring damage requiring replacement less than
  twelve months after insertion of overdenture
• occlusal or prosthetic adjustment more than two
  weeks after delivery of permanent restoration
• recementation of loose prosthesis within two
  weeks of delivery

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• Operative complications
• inadvertent placement of implant into sinus or
  submandibular space
• paresthesia

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Data Analysis

• Descriptive statistics and complication
  frequencies
• Analyses to identify candidate variables (risk
  factors) associated with complications (plt0.15)
• -univariate Cox proportional hazards
  regression model
• Identification of specific variables associated
  with complications (plt 0.05)
• -multivariate Cox proportional hazards
  regression model

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Descriptive Statistics

• Sample Size 677
• Demographic Variables
• Age (yr)
  53.9 13.9
• Gender (female)
  339 (50.1)
• Medically Related Variables
• ASA Status ( gtII) 6 (0.9)
• Medically Compromised (Yes) 57 (8.5)
• Tobacco User (Yes) 57 (10.3)

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• Anatomic Variables
• Jaw
• Maxilla 425 (62.8)
• Location
• Posterior 471 (69.6)
• Implant Proximity
• Between two natural teeth 259 (38.7)
• Between one tooth/one implant 182 (27.1)
• Other configurations 236 (34.2)

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• Anatomic Variables (contd)
• Bone Quality
• Type I 45 (0.7)
• Type II 126 (23.1)
• Type III 137 (25.1)
• Type IV 279 (51.1)

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• Implant Related Variables
• Implant Diameter
• 3.0-3.5mm 195 (30.4)
• 4.0-4.5mm 260 (40.6)
• 5.0mm 168 (26.2)
• 6.0mm 18 (2.8)
• Implant Length
• 4-6mm 10 (1.6)
• 8mm 156 (24.3)
• 11mm 433 (67.5)
• 14mm 42 (6.6)

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• Implant Related Variables (contd)
• Coating
• Uncoated 115 (19.4)
• TPS 187 (31.5)
• HA 291 (49.1)
• Well Size
• 2.0mm 599 (88.7)
• 3.0mm 76 (11.3)
• Staging
• Two-stage 568 (84.0)

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• Abutment Related Variables
• Diameter
• 3-4mm 118 (25.3)
• 5.0-5.5mm 258 (55.2)
• 6.0-6.5mm 91 (19.5)
• Abutment Angulation
• 0 435 (73.9)
• 15 138 (23.4)
• 25 16 (2.7)

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• Prosthetic Related Variables
• Fixed Prosthesis 632 (93.4)
• Other
• Antibiotic Use 574 (84.8)
• Reconstructive Procedures 242 (35.8)

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Implant Complications Identification and
Frequency

Overall Complication Rate 13.9 (94/677)
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• Table 1
  Factors Associated with Overall Implant
  Complications
• Multivariate Cox Model
• Exposure Hazard Ratio
  95 C I p-value
• Tobacco Use 2.31
  1.29, 4.16 0.0051
• (smoker vs. nonsmoker)
• Reconstructive Procedure 1.18
  1.03, 1.34 0.017
• (present vs. absent)
• Implant Staging
  2.56 1.45, 4.55 0.0013
• (one vs. two-stage)
• Age (older vs. younger) 1.0
  0.98,1.0 0.89
• Gender (female vs. male) 0.92
  0.58,1.44 0.72
• Prosthetic Type 1.97
  0.92,4.21 0.083
• (removable vs. fixed)

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• Breakdown of Inflammatory Complications
• 10.2 (69/677) frequency

Impaired wound healing 0.7 (5/677)
Gingival recession 0.4 (3/677)
Peri-implantitis 1.0 (7/677)
Infectious process 2.4 (16/677)
Pain 1.6 (11/677)
Mobility 4.0 (27/677)
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• Table 2 Factors Associated with
  Inflammatory Complications
  Multivariate Cox Model
• Exposure Hazard Ratio
  95 C I p-value
• Tobacco Use
  3.26 1.74, 6.10
  0.0002
• (smoker vs. nonsmoker)
• Reconstructive Procedure 1.17
  1.001, 1.36 0.049
• (present vs. absent)
•  
• Implant Staging 3.03
  1.64, 5.56 0.0004
• (one- vs. two-stage)
• Age (older vs. younger) 1.0
  0.98,1.017 0.77
• Gender (female vs. male) 0.94
  0.56,1.57 0.82
• Jaw (maxilla vs. mandible) 0.64
  0.36,1.15 0.13 

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• Table 3 Factors Associated with
• Operative Complications
• Multivariate Cox Model
• Exposure Hazard Ratio
  95 C I p-value
• Jaw 5.22
  1.01, 27.03 0.048
• (maxilla vs. mandible)
• Reconstructive Procedure 1.84
  1.26, 2.68 0.002
• (present vs. absent)
• Age (older vs. younger) 1.06
  0.99,1.13 0.08
• Gender (female vs. male) 0.40
  0.069,1.96 0.24
• Restorative Dentist 0.41
  0.14,1.17 0.10

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Table 4 Factors Associated with Prosthetic
Complications Multivariate Cox Model

• No variables were found to be statistically
  related with prosthetic complications in the
  multivariate model (plt 0.05).

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DISCUSSION

• Identification of implant complications
• Inflammatory, Operative, and Prosthetic
• Frequency of implant complications
• Overall 13.9 (94/677)
• Inflammatory 10.2 (69/677)
• Prosthetic 2.7 (18/677)
• Operative 1.0 (7/677)

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DISCUSSION (contd)

• Risk factors associated with implant
  complications
• Overall Smoking, one-stage implants, use of
  reconstructive procedures
• Inflammatory Smoking, one-stage implants, use of
  reconstructive procedures
• Operative Jaw (maxilla), use of
  reconstructive procedures
• Prosthetic None identified

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Conclusion

• We hypothesized that we would identify risk
  factors associated with implant complications
  that may be modified by the clinician to enhance
  patient outcome.
• Tobacco use
• Implant staging

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Future Investigations

• Tobacco Use
• -influence on implant complications
• Reconstructive Procedures
• - influence on implant complications

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• Acknowledgements
• Funding Sources Department of Oral and
  Maxillofacial Surgery Research Fund (MGH)
• Oral and Maxillofacial Surgery Foundation (VAV)
• NIH/NIDCR Dentist Scientist Award - K16 DE000275
  (SKC)
• NIH/NIDCR Mid-career Investigators Award K24
  DE000448 (TBD)
• We would like to acknowledge the clinicians and
  support staff of the Faulkner Hospital Dental
  Implant Center (Boston, MA) for their cooperation
  and unrestricted access to patient records.
• Inquiries nancy_mcdermott_at_student.hms.harvard.edu