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Immediate and early implant loading protocols: a literature review of clinical studies.
J Prosthet Dent. 2005 Sep;94(3):242-58.
Attard NJ,Zarb GA.
The purpose of this literature review is to present the outcomes of clinical
studies on immediate and early loading protocols, identify shortcomings, and
suggest a number of questions that still require exploration. English language
clinical studies, limited to peer-reviewed journals between 1975 and 2004, were
reviewed to identify treatment outcomes with these loading protocols. The data
were tabulated from studies reporting on patients treated with fixed and overdenture
prostheses. The former included partially edentulous patients treated with single
or multi-unit prostheses. Within the limitations of this review, it can be concluded
that these treatment protocols are predictable in the anterior mandible,
irrespective of implant type, surface topography, and prosthesis design
(success rates 90%-100%). Limited evidence for the edentulous maxilla
(success rates 90%-100%) and the partially edentulous patient
(success rates 93%-100%) are available, underscoring the need
for further research. Studies suggest that to achieve predictable
results in extraction sites, implant placement should be restricted
to sites without a history of periodontal involvement (success rates 61%-100%).
A number of questions require further exploration. There is a need to thoroughly
investigate clinical outcomes to measure the economic benefit of these protocols
and the impact of treatment on a patient's quality of life. Furthermore, more
accurate long-term studies reporting on treatment protocols for separate clinical
situations are required to allow meaningful comparisons.
Long-term treatment costs associated with implant-supported mandibular prostheses in edentulous patients.
Int J Prosthodont. 2005 Mar-Apr;18(2):117-23.
Attard NJ, Zarb GA, Laporte A.
PURPOSE: The study's aim was to report long-term costs in edentulous patients treated
with mandibular implant-supported prostheses. MATERIALS AND METHODS: Ninety patients
were divided into four groups based on the type of implant prosthesis (fixed or overdenture)
and treatment year. Records were obtained from dental charts, and an economic analysis
from the patient's perspective was conducted. Clinical time associated with various
procedures was measured and applied to the four groups. Salary rates by age, occupation,
and gender were used to value patients' time. Direct clinical and time costs over
10 years were converted to 2002 Canadian dollars using the Consumer Price Index
and discounted at a 3% rate. A sensitivity analysis at an equal salary rate was
carried out to test the robustness of the time costs. RESULTS: Initial treatment
and maintenance costs over the observation period were significantly higher for
fixed compared to overdenture prostheses. A significant improvement in maintenance
costs for the first patient group treated with fixed prostheses was observed
over the follow-up period. Longer term (15 years) treatment costs for the
initial two groups were significantly higher for the fixed group.
The sensitivity analysis at an equal salary rate demonstrated the same trend:
Time costs were significantly higher for the fixed groups. CONCLUSION:
Long-term treatment costs indicated that the mandibular overdenture
was a less expensive treatment compared to the fixed implant prosthesis.
A survey of the use of mandibular implant overdentures in 10 countries.
Int J Prosthodont. 2004 Mar-Apr;17(2):211-7.
Carlsson GE, Kronstrom M, de Baat C, Cune M, Davis D, Garefis P, Heo SJ, Jokstad A, Matsuura M, Narhi T, Ow R, Pissiotis A, Sato H, Zarb GA.
PURPOSE: This preliminary international survey compared provision of implant-retained
overdentures to fixed implant-supported prostheses for edentulous mandibles.
MATERIALS AND METHODS: Questionnaires based on a 2001 Swedish study were sent to
prosthodontists and specialist clinics in nine additional countries. RESULTS:
Response rate varied from 53% to 100% in 10 national surveys and should allow
careful comparison of results. The relationship between implant overdentures
and fixed implant-supported prostheses in treatment of edentulous mandibles
varied much; in Sweden, the proportion of overdentures was 12%, whereas it was
93% in The Netherlands. In all countries, the most common reason for choice of
the overdenture was reduced cost. In all but two countries, the majority of
respondents thought that patients with implant overdentures were equally or
more satisfied with overdentures as those with fixed implant-supported prostheses.
CONCLUSION: There were great differences among the 10 countries in choice of
implant treatment of the edentulous mandible. The relative proportion of
mandibular overdentures to fixed prostheses was low in Sweden and Greece
and varied from one to two thirds in the other countries, except The Netherlands.
Crestal bone loss proximal to oral implants in older and younger adults.
J Prosthet Dent. 2003 Jun;89(6):589-97.
Bryant SR, Zarb GA.
STATEMENT OF PROBLEM: Older adults often have bone loss and may be at risk of bone
resorption around oral implants. PURPOSE: This study tested the hypothesis that there
is no difference in crestal bone loss proximal to oral implants in the complete implant
prosthesis sites of older and younger adults. MATERIAL AND METHODS: Two groups of 35
complete dental implant prosthesis sites (23 screw-retained fixed prostheses and 12
bar-retained overdentures) were selected by matching sites in 32 older adults
(60 to 74 years old with 166 Branemark implants) to sites in 34 younger adults
(29 to 49 years old with 162 Branemark implants) on the basis of possible
confounding factors including gender, prosthetic design, implant number, arch,
year of surgery, and opposing dentition. Statistical comparisons
(Mann-Whitney test at P<.05) were made of mean crestal bone level
at loading and mean annual crestal bone loss during the first year,
first to fourth year, after first year, and after fourth year of loading
with periapical radiographic measurements of the vertical distance in
millimeters from the apical edge of the implant collar to the most apical
initial point of contact between the implant and bone. RESULTS:
No significant differences were found between the groups. Mean bone
levels at loading were 1.4 mm below the collar in both groups and
mean annual crestal bone loss after the first year of loading was
0.04 mm/y in both groups. However, significant differences were found between
some old and young subgroups stratified by arch and prosthetic design.
CONCLUSION: Within the limitations of this study, elders should expect no more
rapid bone resorption around oral implants in edentulous jaws than that seen in
young adults.
A study of dental implants in medically treated hypothyroid patients.
Clin Implant Dent Relat Res. 2002;4(4):220-31.
Attard NJ, Zarb GA.
PURPOSE: The purpose of this study was to investigate the success outcomes of implants
and prosthodontic treatment placed in patients with a previous history of hypothyroidism
that was being controlled with medications. MATERIALS AND METHODS: Twenty-seven female
patients with a medically confirmed history of primary hypothyroid disease who were on
replacement medications at the time of implant surgery were selected as the study group.
They were matched with 29 control patients by age, gender, location (jaw and zone)
of implants, type of prosthesis, and dental status of the opposing arch. Additional
factors studied were medical history, medications, smoking habits, and bone quality
and quantity. RESULTS: There was no statistical difference in the number of implant
failures between the two groups (p = .781). The hypothyroid patients had more soft
tissue complications (p = .018) following stage 1 surgery. More bone loss around
implants in the hypothyroid patients was recorded after year 1 of loading when
compared with loss in their matched controls (p = .017). CONCLUSIONS: This study
suggests that medically controlled hypothyroid female patients treated with dental
implants are not at higher risk of implant failure when compared with matched controls,
and that a history of controlled hypothyroidism does not
appear to be a contraindication for implant therapy with endosseous implants.
Implant prosthodontics in medically challenged patients: the University of Toronto experience.
J Can Dent Assoc. 2002 Feb;68(2):103-8.
Elsubeihi ES, Zarb GA.
A series of prospective studies started in the mid-1980s at the University of
Toronto have provided evidence of the efficacy and effectiveness of implants
in the treatment of the fully and partially edentulous patients. These studies
have focused primarily on treatment outcomes at the surgical and prosthodontic
levels, with an overall failure rate of 7.7% over a 20-year period. Because a
considerable proportion of these failures (4.2%) occurred before insertion of
the prosthesis, and because osseointegration is essentially a wound-healing process,
factors that interfere with healing, including systemic conditions, may contribute to
implant failure. This paper reviews studies on the impact of selected systemic conditions,
including osteoporosis, cardiovascular diseases, diabetes mellitus, and hypothyroidism,
as well as smoking behaviour, on the success or survival of oral implants in patients
treated in the Implant Prosthodontic Unit at the University of Toronto.
A computer-assisted measurement technique to assess bone proximal to oral implants on intraoral radiographs.
Clin Oral Implants Res. 2001 Jun;12(3):225-9.
Wyatt CC, Bryant SR, Avivi-Arber L, Chaytor DV, Zarb GA.
A computer-assisted measurement technique for measuring bone levels proximal
(mesial and distal) to oral implants imaged on standardized intraoral radiographs
offers promise for accuracy and reliability. There were no differences between bone
measurements made directly from bone proximal to implants placed in a dry mandible
and those resulting from the computer-assisted measurement technique. In addition,
there were no differences between measurements made of bone proximal to oral
implants in vivo using the microscope and the computer techniques. The computer
technique had a low intra- and inter-operator variability, and operators found
fewer "unreadable" sites compared to the microscope technique.
The computer-assisted measurement of bone levels proximal to oral implants on
standardized intraoral radiographs offers accuracy and reliability.
Cardiovascular disease and treatment outcomes with osseointegration surgery.
J Prosthet Dent. 1999 May;81(5):533-6.
Khadivi V, Anderson J, Zarb GA.
STATEMENT OF PROBLEM: The frequency of prescription of implant-supported prostheses
demands increased scrutiny of systemic health condition on treatment inclusion and
exclusion criteria. The risks of an impaired healing response in patients with certain
types of cardiovascular diseases (CVD) suggest a possible risk for implant failure in
such patients. PURPOSE: This preliminary study surveyed implant treatment outcome of
patients with cardiovascular diseases. METHODS: A retrospective analysis of 246
consecutively treated patients was conducted. The patients comprised a CVD interest
group of 39 patients, and control subgroups of 98 healthy and 109 patients with a
history of other systemic disease. RESULTS: Differences in implant failure rates
between the groups were not found to be significant. Though the sample size is small,
these results suggest that
CVD may not be a risk factor for successful osseointegration.
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