implantes cortos y bruxismo

Clinical follow-up of unilateral, fixeddental prosthesis on maxillary implants

Monica WahlstromGun-Britt SagulinLeif E. Jansson

Authors’ affiliations:Monica Wahlstrom, Gun-Britt Sagulin, Departmentof Prosthetics at Kista-Skanstull, Public DentalHealth, Stockholm, SwedenLeif E. Jansson, Department of Periodontology atKista-Skanstull, Public Dental Health, Stockholm,Sweden

Corresponding author:Monica WahlstromFolktandvarden SkanstullGotgatan 100118 62 StockholmSwedenTel.: þ 46 8 12316400Fax: þ 46 8 6446271e-mail: [email protected]

Key words: functional disturbances, periodontology, prosthodontics, soft tissue–implant

interactions

Abstract

Aims/Background: The aims of the present study were to evaluate (1) the success rate of

unilateral maxillary fixed dental prosthesis (FDPs) on implants in patients at a periodontal

clinic referred for periodontal treatment, (2) the prevalence of varying mechanical and

biological complications and (3) effects of potential risk factors on the success rate.

Material and methods: Fifty consecutive patients were invited to participate in a follow-up.

The patients had received FDPs on implants between November 2000 and December 2003

after treatment to achieve optimal peridontal health, and the FDPs had been in function for

at least 3 years. A questionnaire was sent to the patients before the follow-up examination.

Forty-six patients with 116 implants were examined. The follow-up comprised clinical and

radiographic examinations and evaluations of treatment outcome.

Results: Before implant treatment, 13% of the teeth were extracted; of these, 80% were

extracted due to periodontal disease. No implants had been lost before implant loading.

One implant in one patient fractured after 3 years of functional loading and three implants

in another patient after 6.5 years. The most frequent mechanical complications were veneer

fractures and loose bridge screws. Patients with peri-implant mucositis had significantly

more bleeding on probing around teeth and implants. Patients with peri-implantitis at the

follow-up had more deep periodontal pockets around their remaining teeth compared

with individuals without peri-implantitis, but these differences were not significant.

Smokers had significantly fewer teeth, more periodontal pockets � 4 mm and a tendency

towards greater marginal bone loss at the follow-up, compared with non-smokers.

Conclusion: In the short term, overloading and bruxism seem more hazardous for implant

treatment, compared with a history of periodontitis.

Many longitudinal studies describe the use

of dental implants for prosthetic rehabilita-

tion of partially dentate patients (Pjeturs-

son et al. 2004). The survival rates of FDPs

on implants are generally high (Schou

2008). But implant survival also includes

implants with extensive bone loss and

implants without the use of a supracon-

struction. Biological and mechanical com-

plications occur, and there is some

evidence that patients with a history of

periodontal disease may be more prone to

peri-implantitis (Schou 2006). Hence, the

success rate of implant therapy, namely,

that the implant is in function and causes

no complications (Albrektsson et al. 1986;

Smith & Zarb 1989), may be a more

pertinent variable to study.

To implement implant therapy success-

fully, we have to minimize risk factors.

Some well-known risk factors for implant

therapy include tobacco use (Bain 2003),

Date:Accepted 11 February 2010

To cite this article:Wahlstrom M, Sagulin G-B, Jansson LE. Clinical follow-up of unilateral, fixed dental prosthesis on maxillaryimplantsClin. Oral Impl. Res. 21, 2010; 1294–1300.doi: 10.1111/j.1600-0501.2010.01948.x

1294 c� 2010 John Wiley & Sons A/S

mailto:[email protected]

insulin-dependent diabetes, and difficulties

in maintaining proper oral hygiene caused by

the design or a bridge of patients (Esposito et

al. 1998; Serino & Strom 2009). In addition,

a history of periodontitis has been proposed

to be a possible risk factor. Roos-Jansaker

(2007) reported that implant loss is signifi-

cantly correlated with periodontitis, and

peri-implant lesions are usually found after

10–14 years of fixed dental prosthesis (FDP)

function. In another study (De Boever et al.

2009), the incidences of peri-implantitis and

implant loss in individuals with generalized

aggressive periodontitis were found to be

more frequent compared with periodontally

healthy individuals. No reports claim with

certainty that individuals with periodontitis,

which is associated with tooth loss, are more

susceptible to implant complications than

individuals without periodontitis. Only a

few studies specify the causes of tooth loss

before implant placement. The association

between bruxism (tooth grinding and clench-

ing) and implant failure has been studied in

several clinical studies but randomized-con-

trolled studies are lacking to support a causal

relationship between overload and implant

failure (Lobbezoo et al. 2004; Hobkirk &

Wiscott 2006; Lobbezoo et al. 2006).

The aims of the present study were to

evaluate (1) the success rate of unilateral

maxillary FDPs on implants in patients at a

periodontal clinic referred for periodontal

treatment, (2) the prevalence of varying

mechanical and biological complications

and (3) the effects of potential risk factors

on the success rate.

Material and methods

Subjects

This retrospective study followed up conse-

cutive patients referred to the Departments

of Periodontal and Prosthetic Dentistry,

Public Dental Service, Skanstull, Stock-

holm, for periodontal or prosthetic treat-

ment. The inclusion criteria were as follows:

� Treatment with implant-supported

FDPs positioned unilaterally in the max-

illa on two or more implants between

November 2000 and December 2003.

� Natural teeth present on the contralat-

eral side of the maxilla.

� FDPs in function for at least 3 years.

Fifty patients met the inclusion criteria.

Three patients had died, and one patient

could not be found. The final study group

comprised 46 patients with 116 implants

(13 men and 33 women). The mean patient

age at the time of prosthetic treatment was

59 years (range 36–84). The mean time

between prosthetic loading of the FDPs

and the clinical and radiographic examina-

tions at the follow-up was about 5 years

(median 58 months; mean 61.3 months;

range 40–84).

A letter sent to patients’ home addresses

explained the study and invited participa-

tion. Enclosed with the letter was a ques-

tionnaire containing subjective questions

about health, satisfaction with FDP es-

thetics, chewing ability, oral hygiene, and

recall visits with dental hygienists. Pa-

tients were asked to fill out the question-

naire before the follow-up.

Implant treatment

Before implant treatment, all patients (if

needed) were periodontally treated to

achieve periodontal health. Periodontists

and dental hygienists cooperated in an

attempt to motivate all smokers to quit.

Patients who achieved satisfactory perio-

dontal conditions qualified for implant

treatment. In most instances, periodontists

at the Department of Periodontal Dentis-

try, Public Dental Service, Skanstull,

Stockholm, performed implant surgery.

Oral surgeons at two hospitals in Stock-

holm installed a few implants.

After a minimum of 3 months of sub-

merged implant healing, surgical abut-

ments were fitted. Shortly thereafter, the

FDPs were placed as per the manufacturer’s

instructions on either (1) Cresco CtC in-

serts (Cresco Ti precision methods

; Cresco

Ti Systems Sarl; Lausanne, Switzerland) or

(2) ASTRA Techs

(Molndal, Sweden) abut-

ments. Between November 2000 and

December 2003, two dentists at the

Department of Prosthetic Dentistry, Pub-

lic Dental Service, Skanstull, Stockholm,

provided prosthetic treatment. All patients

were instructed to maintain proper hygiene

of their FDPs and the remaining teeth.

Dental hygienists at the periodontal clinic

provided supportive treatment for all pa-

tients with a history of periodontitis.

Study variables

A periodontist determined the marginal

bone level on radiographs. The patients

were then divided into three groups de-

pending on the degree of marginal bone of

most remaining teeth:

� Mean bone loss o1/3 of the root

length.

� Mean bone loss �1/3 and o2/3 of the

root length.

� Mean bone loss �2/3 of the root

length.

Clinical variables determined before

periodontal and prosthetic treatment,

such as probing pocket depth (PPD) and

bleeding on probing (BOP), were extracted

from patients’ dental records. The same

periodontist determined periodontal vari-

ables at the follow-up.

These variables were extracted from den-

tal records, patient questionnaires, and

clinical examinations at the follow-up:

� Age.

� Gender.

� Medical history and medications.

� Questions about the function of the

FDP.

� FDPs’ time in function.

� Smoking habits: non-smoker, former

smoker, current smoker.

� Number of remaining teeth before

treatment and at the follow-up.

� Reasons for tooth extractions.

� Temporomandibular disorders: occur-

rence of subjective and objective symp-

toms, parafunctions and interferences,

occlusal wear, and use of interocclusal

appliance.

� Bone augmentation.

� Number of implants.

� Implant sites.

� Implant system.

� Design of prosthetic construction:

material in the supraconstruction

(Table 1), cemented or screw-retained

FDP, type of abutments, number of

bridge units and cantilevers (Table 2).

� BOP.

� PPD at four sites per tooth and implant

using a periodontal measuring probe

(CP-12, Hu-Friedy, Chicago, IL, USA).

Table 1. Frequency distribution of bridgematerial in the fixed dental prosthesis

Material N

Titanium/sinfony 1Gold/porcelain 34Titanium/porcelain 1Wirobond/porcelain 10

Wahlstrom et al �Clinical follow-up of unilateral fixed dental prosthesis

c� 2010 John Wiley & Sons A/S 1295 | Clin. Oral Impl. Res. 21, 2010 / 1294–1300

With light force, the probe was verti-

cally inserted into the pocket between

the mucosa and the implant.

� Peri-implant mucositis, defined by

BOP, PPDo4 mm, and without loss

of marginal bone around the implant.

� Peri-implantitis, defined by the color

and shape of peri-implant mucosa,

bleeding or pus on probing, PPD �4 mm, and marginal bone loss mesial

and distal of the fixtures 42 mm clearly

visible on radiographs, compared with

baseline radiographs made at the first

follow-up visit, in most cases 1 year

after prosthetic loading

� Implant loss.

� Mechanical complication of the supra-

construction and/or the implant during

functional loading.

� Difficulties in maintaining proper oral

hygiene caused by the design of the

bridge or patients’ motoric disability.

� Maintenance program for oral health.

Statistics

The Statistical Package for the Social

Sciences (SPSS, version 4.0 for the PC;

SPSS Inc., Chicago, IL, USA) was used to

analyze the data. In all analyses, the sta-

tistical computational unit was at the sub-

ject level. The Kruskal–Wallis test

investigated between-group differences

based on investigated variables. The

w2-test was used to investigate the correla-

tions between mucositis/peri-implantits

and smoking history. Results were consid-

ered statistically significant at Po0.05.

Results

Before implant treatment, 13% of the teeth

were extracted; of these, 80% were ex-

tracted due to periodontal disease. Fifty-

six percent of the patients had a mean bone

loss of o1/3 of the root length, while the

mean marginal bone loss of the remaining

teeth in 15% of the patients was �2/3 of

the root length. Thus, 29% of the indivi-

duals had a mean bone loss between 1/3

and 2/3 of the root length. Figs 1 and 2

illustrate the distributions of PPD � 4

mm and �6 mm at baseline and at the

follow-up.

The frequency distributions at the

patient level of the bridge material in

the supraconstructions are presented in

Table 1. Gold/porcelain was the most fre-

quent material and was used in 74% of the

cases. The Astra Tech Systems

was used

for 111 implants in 44 patients. The Nobel

Biocare ABs

(Goteborg, Sweden) system

was used for five implants in two patients.

Twenty-eight of the 46 FDPs’ supracon-

structions were made of components in the

Astra Tech Systems

and 18 of components

in the Cresco Ti precision methods

(Cresco Ti Systems Sarl).

Table 2 displays the number of implants,

bridge units, and cantilever segments. Bone

augmentation techniques before implant

treatment were used in 50% of the cases

and were not correlated with the presence

of mucositis, peri-implantitis, or implant

loss. Most patients (80%) visited a dental

hygienist at least once a year, and 54%

visited a dental hygienist more than once a

year. During the follow-up period, two

patients received FDPs on the contralateral

side in the maxilla due to extractions for

periodontal reasons.

The relative frequency distributions of

answers to anamnestic variables in the

questionnaires that patients filled in before

the follow-up are presented in Table 3. No

patient regretted choosing implant treat-

ment. All but one patient were satisfied

with the esthetic result of their FDPs. The

dissatisfied patient (with the esthetics)

complained because the titanium abutment

was exposed buccally on one implant.

Biological complications

At the follow-up, five patients stated that

they were smokers and 26 stated that they

were former smokers. The means for perio-

dontal variables in teeth associated with a

Table 2. The frequency distribution at thesubject level of number of implants, bridgeunits, and cantilever segments

Variable 0 1 2 3 4 5 6

Number ofimplants

26 16 4

Number ofbridge units

13 23 6 3 1

Number ofcantileversegments

38 8

%

90100

607080

405060 Baseline

Follow-up

2030

010

Number of periodontalpockets ≥4 mm

0-9 10-19 20-29 ≥30

Fig. 1. Distribution of probing pocket depths

�4 mm at baseline and at the follow-up.

Table 3. The relative frequency distribution (%) of answers to anamnesis variables on thequestionnaire

Variable Yes (%) No (%)

Smoker 11 89Former smoker 57 43Takes snuff 7 93Subjective symptoms of temporomandibular disorders 13 87Bruxism 31 69Frequent headache 9 91Use of interocclusal appliance 28 72Bleeding around implants 35 65Satisfied with implants 89 11Chewing habits were changed 13 87Subjective symptoms caused by the implants 20 80Satisfied with the esthetics of the implants 98 2Subjective feeling of difference between implants and teeth 13 87Regretted the choice of implant treatment 0 100

%

90100

7080

405060

2030

010

Number of periodontalpockets ≥6 mm

0-9 10-19 20-29 ≥30

Fig. 2. Distribution of probing pocket depths

�6 mm at baseline and at the follow-up.


1296 | Clin. Oral Impl. Res. 21, 2010 / 1294–1300 c� 2010 John Wiley & Sons A/S

smoking history are presented in Table 4.

Former smokers had significantly fewer

teeth, more periodontal pockets �4 mm

at the follow-up, and a tendency (P¼ 0.06)

towards more marginal bone loss compared

with non-smokers. Smokers had signifi-

cantly (Po0.01) more tooth sites with

periodontal pockets �6 mm at the fol-

low-up compared with non-smokers and

former smokers. Table 5 displays the

frequency distributions of subjects with

peri-implant mucositis and peri-implanti-

tis associated with a smoking history.

Smoking was not significantly correlated

with the presence of peri-implant mucosi-

tis and peri-implantitis (P40.05).

Peri-implant mucositis was diagnosed in

10 patients (Table 5). These 10 patients

had significantly more bleeding tooth sites

and periodontal pockets �4 mm and

�6 mm during probing around the teeth,

compared with patients without peri-im-

plant mucositis (P¼0.05, Table 6). Two

patients had peri-implantitis during func-

tional loading and more periodontal pock-

ets and bleeding tooth sites compared with

patients without peri-implantitis: one pa-

tient with peri-implantitis had a mean

marginal bone loss �1/3 of the root

length; the other had a mean marginal

bone loss �2/3.

Mechanical complications

No early implant failure was documented.

Two patients had lost four implants due to

implant fracture. In one of these patients,

all three implants fractured 6.5 years after

functional loading, in a four-unit FDP

without a cantilever, but involved the

canine. The patient used a soft interocclu-

sal appliance. In the other patient, the

posterior implant of two implants fractured

after 3 years. The construction had one

distal cantilever, and the patient did not

use a stabilization splint.

One patient with peri-implant mucositis

and bruxism diagnoses had one fractured

abutment after 6 years and 8 months of

loading. The abutment was exchanged, and

the FDP is still in function. No significant

differences in mechanical complications

were found between the two systems of

supraconstruction fabrication on Astra

Techs

implants: Astra abutments or the

Cresco Ti precision methods

. Ten of the 46

suprastructures had lost their screw reten-

tion during functional loading and had to be

reset.

Veneer fractures were recorded in nine

out of 46 FDPs. Six of those nine FDPs

were made of gold and porcelain and two

were made of wirobond and porcelain; this

difference was not significant. The only

suprastructure made of titanium and por-

celain showed a veneer chipping fracture.

The frequencies of veneer fractures were

not significantly correlated with use of

occlusal appliance or bruxism.

The survival rate of the FDPs was 94%

(three out of 46 FDPs were lost). Two of

those three patients received new implants

and new FDPs, but the new implants are

not included in the results. One individual

lost the suprastructure due to loosening of

bridge screws. The implants resulted in no

complications, although the supracon-

struction could not be examined at the

follow-up; this patient was mentally dis-

abled at the time of examination.

Twenty-one out of 46 patients had

neither biological nor mechanical compli-

cations in their FDPs during functional

loading. Thus, the success rate for the

patients was 46%. Biological complica-

tions were observed in 11 patients (24%)

and one or several mechanical complica-

tions of varying severities in 14 patients

(30%). Four of these patients (9%) had

biological and mechanical complications

during functional loading.

Discussion

The present study consisted of 46 patients

and the analyses were performed at the

patient level. Thus, the material consisted

of a limited number of data and the ana-

lyses were performed using non-parametric

tests as these tests have the advantage of

not requiring the assumption of normality

or the assumption of homogeneity of var-

iance. The multiple comparisons between

different groups may result in mass signifi-

cance, which means an increased risk of

rejecting a correct hypothesis.

Consensus statements and recommen-

dations (Lang et al. 2004) regarding implant

survival and complications for implant-

supported FDPs in an ordinary population

noted that the cumulative survival rate of

FDPs that are supported by oral implants

was 95% after 5 years in function and

86.7% after 10 years in function. In our

limited material, the survival rate of FDPs

was 93.5% after 3–7 years in function.

Most studies are based on the FDP survival

rate from treatment in the mandible and

the maxilla, while our study only reports

results from maxillary treatment. Jemt &

Lekholm (1995) observed a lower FDP

survival rate in the maxilla.

The Pjetursson et al. (2004) review of

four studies on the effects of FDPs on

Table 4. Median values (range) for periodontal variables associated with smoking history

Smoking history n Number of teethat follow-up

Number of tooth siteswith periodontalpockets �4 mm

Number of tooth siteswith periodontalpockets �6 mm

Number ofbleeding toothsites at probing

Percentage (SD) of subjectswith a marginal bone loss41/3 of root length

Smokers 5 20 (14–29) 4 (0–49) 4 (3–23) 2 (0–37) 40 (54.8)Former smokers 26 17 (8–24) 3.5 (0–23) 0 (0–3) 3 (0–34) 53.8 (50.8)Non-smokers 15 23 (16–28) 1 (0–4) 0 (0–1) 2 (0–44) 26.7 (45.8)

Table 5. Frequency distributions of subjects with peri-implant mucositis and peri-implan-titis associated with smoking history

Smoking history n Number of patientswith mucositis

Number of patientswith peri-implantitis

Smokers 5 3 1Former smokers 26 5 1Non-smokers 15 2 0Total 46 10 2



implants found an implant success rate of

61% after 5 years. Thus, 39% of the

patients had some type of complication in

the first 5 years of loading. The success

rate in our material was 46%, which

means that we had more complications

than these studies reported. The more

recent Pjetursson et al. (2007) review of

nine cohort studies found that the criteria

for reporting biological and mechanical

complications varied between the studies.

In this study, we observed a rather low

incidence of biological complications, such

as increased PPDs and BOP, infections of

peri-implant mucosa, and remaining teeth

at the follow-up, although many patients

had a history of periodontitis. This might

be due to (1) the oral hygiene information

and instructions that all patients received

before treatment with implants and (2)

supportive periodontal therapy afterward.

The follow-up period is relatively short,

sometimes only slightly 43 years (range

40–84 months). Several studies point out

that peri-implant mucositis and peri-im-

plantitis are common clinical findings in

periodontally compromised patients who

had their FDPs in function for 5 or more

years (Hardt et al. 2002; Karoussis et al.

2003; Roos-Jansaker et al. 2006a, 2006b,

2006c).

In a review of nine studies of patient

groups that received periodontal treatment

and groups that did not have periodontitis,

Ong et al. (2008) found that peri-implanti-

tis was about seven times as common in

treated periodontitis patient groups. Over-

all, the non-periodontitis patients demon-

strated better outcomes than patients with

periodontitis. The studies varied in their

reporting of periodontal treatment, quality

of supportive periodontal therapy, and con-

founders such as smoking history and out-

come criteria.

Nevertheless, several studies indicate that

patients treated for periodontitis more often

develop complications around implants

than non-periodontitis patients. Evidence

is stronger for implant survival than implant

success. But Shou (2006) reviewed two

studies on the treatment outcome of im-

plant therapy in (1) patients who lost teeth

due to periodontitis and (2) patients who had

teeth extracted for other reasons. Although

they found no significant differences asso-

ciated with the survival rates of implants

after 5 and 10 years, significantly more

patients were affected by peri-implantitis

with increased bone loss around the im-

plants in patients treated for periodontitis.

The 10-year longitudinal Karoussis et al.

(2007) study found significant differences in

the implant survival and success rate be-

tween patients with a history of chronic

periodontitis and periodontally healthy in-

dividuals. ‘‘By installing oral implants into a

partially dentate dentition, ecological con-

ditions of the oral cavity, which influence

biofilm formation on implants, vary from

the totally edentulous individual (Mombelli

et al. 1995).’’ Residual pockets may repre-

sent niches for infection on implants; con-

sequently, the importance of periodontal

treatment of residual dentition before place-

ment of osseointegrated oral implants has

been emphasized (Bragger et al. 1997).

Peri-implantitis and soft tissue compli-

cations, such as peri-implant mucositis,

occurred in 8.6% of our patients after 5

years. This is a rather low incidence com-

pared with the Roos-Jansaker (2007) study,

which reported that 79% of the patients

had peri-implant mucositis and 16% of the

patients had peri-implantitis after 9–14

years. In our study, we followed the same

criteria for biological complications as

Roos-Jansaker, and we found that 10 pa-

tients (22%) had peri-implant mucositis

and two patients (4%) had peri-implantitis

after a functional loading of at least 3 years.

Of the two patients with peri-implanti-

tis, one had peri-implantitis on two out of

three implants on a three-unit FDP and

was one of the severely periodontally com-

promised patients with a general marginal

bone-level reduction of 42/3 of the root

length. This patient had not followed the

oral hygiene maintenance care program or

attended recall visits to the dental hygie-

nist; had poor oral hygiene; smoked 20

cigarettes/day; and despite a clenching/

grinding habit, refused to use the occlusal

appliance we recommended. The other

patient with peri-implantitis had fractured

all three implants in a four-unit FDP that

was in function (described earlier under

mechanical complications).

The Lindhe & Meyle (2008) consensus

report shows that peri-implant infections

in all types of implant therapy are a very

common lesion. In the workshop, they

reported that peri-implant mucositis oc-

curred in 80% of the subjects and 50% of

the implant sites. Peri-implantitis was

identified in 28–56% of the subjects and

in 12–43% of the implant sites. Peri-im-

plant infections are usually linked with

poor oral hygiene, a history of periodontitis

(De Boever et al. 2009), and cigarette

smoking. Other risk factors, such as dia-

betes, alcohol consumption, and genetics,

are less well established, but the patient

must be informed about the higher risk.

Pjetursson et al. (2004) reported mechan-

ical complications in FDPs after 5 years.

Only three available studies expressed

Table 6. Median values (range) for periodontal variables associated with the presence of peri-implant mucositis, peri-implantitis, andimplant loss

Diagnosis N Number ofteeth atfollow-up

Number ofperiodontalpockets� 4 mm

Number ofperiodontalpockets� 6 mm

Number ofbleeding sitesat probing

Percentage (SD) ofsubjects with amarginal bone loss� 1/3 of root length

Peri-implant mucositisþ 10 19.5 (13–26) 3.5 (0–49) 2 (0–23) 8.5 (0–44) 30 (48.3)� 36 20 (8–29) 1 (0–13) 0 (0–3) 1.5 (0–21) 47.2 (50.6)

Peri-implantitisþ 2 17.5 (16–19) 26.5 (4–49) 10.5 (0–23) 22 (7–37) 100 (-)� 44 20 (8–29) 1.5 (0–23) 0 (0–3) 2 (0–44) 40.9 (49.7)

Implant loss (due to fracture)þ 2 17.5 (16–19) 2 (0–4) 0 (0–0) 15.5 (7–24) 100 (-)� 44 20 (8–29) 1.5 (0–49) 0 (0–23) 2 (0–44) 40.9 (48.2)



success as the number of patients without

any complications during the observation

period. There is no available detailed infor-

mation regarding whether or not all com-

plications were reported from the dental

records – including those of a minor degree.

We reported even the smallest veneer frac-

ture polished during functional loading.

Pjetursson et al. (2004) also reported that

the most common mechanical complica-

tion was veneer fractures in 13.2% of

FDPs; the second was loss of screw ac-

cess-hole restoration, which occurred in

8.2% of the anchors; and the third was

abutment or occlusal screw loosening,

which occurred in 5.8% of FDPs.

In this study, we found about 20%

veneer fractures, fractured abutments, or

loose bridge screws during the functional

time in 22% of the patients and loss of

screw access-hole restoration in two (4,3%)

patients. Three patients reported cheek

biting or enunciation problems. Lang

et al. (2004) reported that implant fracture

is a rare mechanical complication (0.4%

after 5 years and 1.8% after 10 years). We

documented two individuals (4.3%) with

abutment fractures and two (4.3%) with

implant fractures. All were identified as

bruxers. In our limited material, one bruxer

affected the survival and success rates; this

patient had multiple complications during

the follow-up period: loosening of supras-

tructure, peri-implantitis, fracture of abut-

ments, and finally fracture of implants.

Bragger et al. (2001) found that mechan-

ical complications were associated with

bruxism and extension of FDPs on im-

plants; consequently, in bruxers, more im-

plant-supported FDPs than FDPs on teeth

had porcelain fractures. Eighteen patients

were registered as bruxers from anamnesis

data or the clinical examination. Six of

these 18 patients had biological and/or

mechanical complications during the fol-

low-up period. According to Roos-Jansaker

(2007), the complications were clustered in

patients. The four implants lost due to

implant fracture in the material were in

two patients, who were bruxers. Implant

losses and early or late failures were not

found for other reasons. Implant fractures

occurred after earlier warning signs such as

loosening suprastructures. Plausible expla-

nations for the increased risk of mechanical

complications on implant-supported FDPs

(compared with tooth-supported FDPs) are

(1) lack of flexibility in periodontal fibers

and (2) limited proprioception due to the

absence of a periodontal ligament, which

leads to decreased tactile sensitivity. It is

possible that forces applied on implants

during bruxism are even larger than during

mastication (Engel et al. 2001).

Trulsson (2005) concluded in his

study that humans use periodontal afferent

signals to control jaw actions. When

dental implants are loaded mechanically,

a sensation (often called osseoperception)

is evoked. The sensory signals underlying

this phenomenon vary qualitatively

from signals evoked when natural teeth

are loaded. This can impair fine-

motor control of the mandible and put

more force on implants than on natural

teeth.

In conclusion, the success rate at the

patient level was found to be 46%. How-

ever, the success rate was affected by our

registrations of common and less serious

complications such as small veneer frac-

tures. Mechanical complications were

more frequent than biological complica-

tions in implant-supported FDPs during

the first 3 years of loading in periodontally

healthy individuals who received adequate

dental hygiene support before and after

treatment with implants. Detrimental

complications can be expected in indivi-

duals with extreme occlusal forces,

indicating that those forces may even be a

bigger challenge to overcome when rehabi-

litating patients with implant-supported

FDPs.

Acknowledgements: The authors

thank Ms Birgitta Sunehed for technical

and administrative assistance.

References

Albrektsson, T., Zarb, G., Worthington, P. &

Eriksson, A.R. (1986) The long-term efficacy of

currently used dental implants: a review and

proposed criteria of success. The International

Journal of Oral & Maxillofacial Implants 1:

11–25.

Bain, C.A. (2003) Implant installation in the smok-

ing patient. Periodontology 2000 33: 185–183.

Bragger, U., Aeschlimann, S., Burgin, W., Ham-

merle, C.H. & Lang, N.P. (2001) Biological and

technical complications and failures with fixed

dental prosthesis on implants and teeth after 4 to

five years of function. Clinical Oral Implants

Research 12: 26–34.

Bragger, U., Burgin, W.B., Hammerle, C.H. & Lang,

N.P. (1997) Associations between clinical

parameters assessed around implants. Clinical

Oral Implants Research 8: 412–421.

De Boever, A.L., Quirynen, M., Coucke, W., Theu-

niers, G. & DeBoever, J.A. (2009) Clinical and

radiographic study of implant treatment outcome

in periodontally susceptible and non-susceptible

patients: a prospective long-term study. Clinical


Engel, E., Gomez-Roman, G. & Axman-Krcmar, D.

(2001) Effect on occlusal wear on bone loss

and periotest value of dental implants. The

International Journal of Prosthodontics 14:

144–150.

Esposito, M., Hirsch, J.M., Lekholm, U. & Thom-

sen, P. (1998) Biological factors contributing to

failures of osseointegrated oral implants. (I). Suc-

cess criteria and epidemiology. European Journal

of Oral Sciences 106: 527–551.

Hardt, C.R., Grondahl, K., Lekholm, U. &

Wennstrom, J.L. (2002) Outcome of implant

therapy in relation to experienced loss of perio-

dontal bone support: a retrospective 5-year study.

Clinical Oral Implants Research 13: 488–494.

Hobkirk, J.A. & Wiscott, H.W.A. (2006) Biomecha-

nical aspects of oral implants. Consensus report of

working group 1. Clinical Oral Implants research

17 (Suppl. 2): 52–54.

Jemt, T. & Lekholm, U. (1995) Implant treatment

in edentulous maxillae; a 5-year follow-up

report on patients with different degrees of jaw

resorption. The International Journal of Oral &

Maxillofacial Implants 10: 303–311.

Karoussis, I.K., Kotsovilis, S. & Fourmousis, I.

(2007) Review. A comprehensive and critical re-

view of dental implant prognosis in periodontally

compromised partially edentulous patients.

Clinical Oral Implants Research 18: 669–679.

Karoussis, I.K., Salvi, G.E., Heitz-Mayfield, L.J.A.,

Bragger, U., Hammerle, C.H.F. & Lang, N.P.

(2003) Long term implant prognosis in patients

with and without a history of chronic

periodontitis; a 10-year prospective cohort study

of ITI dental implant system. Clinical Oral

Implants Research 14: 329–339.

Lang, N.P., Berglundh, T., Heitz-Mayfield, L.,

Pjetursson, B.E., Salvi, G.E. & Sanz, M. (2004)

Consensus statements and recommended clinical

procedures regarding implant survival and compli-

cations. The International Journal of Oral &

Maxillofacial Implants 19: 150–154.

Lindhe, J. & Meyle, J. (2008) Peri-implant diseases:

consensus report of the sixth European workshop

on periodontology. Journal of Clinical Perio-

dontology 35 (Suppl. 8): 282–285.

Lobbezoo, F., Brouwers, J.E., Cune, M.S. & Naeije,

M. (2004) Dental implants in tooth grinders.



Nederlands Tijdschrift voor tandheelkunde 111:

85–90.

Lobbezoo, F., Van der Zaag, J. & Naeije, M. (2006)

Bruxism: its multiple causes and its effects on

dental implants – an updated review. Journal of

Oral Rehabilitation 33: 293–300.

Mombelli, A., Marxer, M., Gaberthuel, T., Grun-

der, U. & Lang, N.P. (1995) The microbiota of

osseointegrated implants in patients with a history

of periodontitis. Journal of Clinical Perio-

dontology 22: 124–130.

Ong, C.T., Ivanovski, S., Needleman, I. G., Retzepi,

M., Moles, D. R., Tonetti, M. S. & Donos, N.

(2008) Systematic review of implants outcomes in

treated periodontitis subjects. Journal of Clinical

Periodontology 35: 438–462.

Pjetursson, B.E., Lang, N.P., Bragger, U. & Zwah-

len, M. (2007) Comparison of survival and com-

plication rates of tooth-supported fixed dental

prostheses (FDPs) and implant supported FDPs

and single crowns (SCs). Clinical Oral Implants

Research 18 (Suppl. 3): 97–113.

Pjetursson, B.E., Tan, K., Lang, N.P., Bragger, U.,

Egger, M. & Zwahlen, M. (2004) A systematic

review of the survival and complication rates

of fixed partial dentures (FDPs) after an

observation period of at least 5 years. Clinical


Roos-Jansaker, A.M. (2007) Long time follow up of

implant therapy and treatment of periimplantitis.

Swedish Dental Journal 188 (Suppl.): 7–66.

Roos-Jansaker, A.M., Lindahl, C., Rehnvert, H.

& Renvert, S. (2006a) Nine-to-fourteen year

follow-up of implant treatment. Part I: implant

loss and associations to various factors. Journal of

Clinical Periodontology 33: 283–289.

Roos-Jansaker, A.M., Lindahl, C., Rehnvert, H. &

Renvert, S. (2006b) Nine-to-fourteen year

follow-up of implant treatment. Part II: presence

of periimplant lesions. Journal of Clinical Perio-

dontology 33: 290–295.

Roos-Jansaker, A.M., Lindahl, C., Rehnvert, H. &

Renvert, S. (2006c) Nine-to-fourteen year follow-

up of implant treatment. Part III: factors

associated with periimplant lesions. Journal of

Clinical Periodontology 33: 296–301.

Serino, G. & Strom, C. (2009) Peri-implantitis in

partially edentulous patients: association

with inadequate plaque control. Clinical Oral

Implants Research 20: 169–174.

Shou, S. (2006) Outcome of implant therapy in

patients with previous tooth loss due to perio-

dontitis. Clinical Oral Implants Research

17: 104–123.

Shou, S. (2008) Implant treatment in perio-

dontitis-susceptible patients: a systematic review.

Journal of Oral Rehabilitation 35 (Suppl. 1):

9–22.

Smith, D.E. & Zarb, G.A. (1989) Criteria for

success of osseointegrated endosseous im-

plants. Journal of Prosthetic Dentistry 62: 567–

572.

Trulsson, M. (2005) Sensory and motor function of

teeth and dental implants: basis for osseopercep-

tion. Clinical and Experimental Pharmacology

and Physiology 32: 119–122.



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