are predictors for implant bone loss act constantly across long-term function?

Are Predictors for Implant Bone Loss Act Constantly Across Long-Term Function?

Ronen Ofec, DMD* ; Liran Levin, DMD ; Daniel Nitzan, DMD ; Devorah Schwartz-Arad, DMD, PhD

* M.Sc. program in Biostatistics

* Praviate dental practice, Tel-Aviv, Israel

School of Mathematical sciences, Tel-Aviv university

Are Predictors for Implant Bone Loss Act Constantly Across Long-Term Function?

Ronen Ofec, DMD* ; Liran Levin, DMD ; Daniel Nitzan, DMD ; Devorah Schwartz-Arad, DMD, PhD

* M.Sc. program in Biostatistics

* Praviate dental practice, Tel-Aviv, Israel

Marginal Bone Loss (MBL)

• Implant success criteria for the research community

• Measurement for the diagnosis of Peri-implantitis

• No standardization for MBL measurement

• No consensus for the classification of acceptable vs. advanced bone loss

Purpose of the study

• To identify predictors for MBL in long term follow-up

• To evaluate the interaction between predictors

and function-time

• To construct statistical model with respect to clustered observations

Participants & Methods

• Historical prospective (retrospective) cohort study design

• 13 years ago, 256 patients who received totally 936

implants in a 2-stage protocol

• Schwartz-Arad Surgical center by a single surgeon

• Recall program, clinical and radiographic follow-up

The dependent variable

Marginal bone loss

No. exposed threads

Bone loss rate (mm per function year )

Acceptable vs. Advanced bone loss

Last x-ray

Statistical analysis & results

Prevalence of acceptable and advanced bone loss across function-time

Function time[month]

Ma

rgin

al b

on

e lo

ss

20 40 60 80 100 120 140

Acce

pta

ble

Ad

va

nce

d

0.0

0.2

0.4

0.6

0.8

1.0

20.7%

Modeling advanced bone loss

Step 1 : The relevant predictorsMethod : Logistic regression with forward step selectionResults : The sequence variables entered to the equation

1. Function time

2. Implant surface (cpTi, HA & TPS)

3. Premature spontaneous exposure4. Smoking status at 1st surgery

5. Implant Diameter


Step 2 : The interaction between function time and predictorsMethod : Deviance analysis for goodness of fitResults :

Model with interaction

Model without interaction

595

605

615

625

635

645

655

2 Years 3 Years 4 Years 5 Years 6 Years

Deviance

• Interaction terms yield in a better fit• The strongest interaction at 3 years of function


Step 3 : Final models for advanced bone lossMethod : General estimation equations (GEE)Results : Odds ratio at short and long term function-time

Function-time

< 3 Years

Function- time

≥ 3 Years

HA coatingProtective 0.26

[0.09-0.80]

Risk 2.51

[1.08-5.82]



Function-time

< 3 Years

Function- time

≥ 3 Years


[0.09-0.80]

Risk 2.51

[1.08-5.82]

TPS surfaceRisk 8.79

[3.42-22.58]



Function-time

< 3 Years

Function- time

≥ 3 Years


[0.09-0.80]

Risk 2.51

[1.08-5.82]


[3.42-22.58]

Spontaneous

exposure

Risk 2.42

[1.35-4.35]



Function-time

< 3 Years

Function- time

≥ 3 Years


[0.09-0.80]

Risk 2.51

[1.08-5.82]


[3.42-22.58]

Spontaneous

exposure

Risk 2.42

[1.35-4.35]

Smoker at 1st

surgery

Risk 4.81

[2.13-10.88]



Function-time

< 3 Years

Function- time

≥ 3 Years


[0.09-0.80]

Risk 2.51

[1.08-5.82]


[3.42-22.58]

Spontaneous

exposure

Risk 2.42

[1.35-4.35]

Smoker at 1st

surgery

Risk 4.81

[2.13-10.88]

Implant

diameter

Protective 0.26

[0.12-0.58]

Forest plot for Odds ratioconfidence intervals

0.02 0.2 2 20

< 3 Years

Smoker

Spontaneousexposure

TPS surface

HA coating

O.R=1

Diameter


0.02 0.2 2 20

≥ 3 Years

Smoker

Spontaneousexposure

TPS surface

HA coating

O.R=1

Diameter


0.02 0.2 2 20

< 3 Years ≥ 3 Years

Smoker

Spontaneousexposure

TPS surface

HA coating

O.R=1

Diameter

Conclusions

• Predictors for MBL do not act constantly across function-time

• Research findings should be judged according to

the study follow-up period

• The importance of long term follow-up

• Standardization concerning MBL measurements

• Consensus for the classification of advanced bone loss

Thanks

[email protected]

are predictors for implant bone loss act constantly across long-term function?

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