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Open contacts adjacent to dental implant restorations: Etiology, incidence, consequences, and correction

  • Columbia University, College of Dentistry

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Background: The aim of this investigation was to evaluate the potential causes, clinical significance, and treatment of open contacts between dental implant restorations and adjacent natural teeth. Types of studies reviewed: The authors searched the dental literature for clinical trials in humans that addressed the incidence of open contacts that develop after implant restorations are placed next to teeth. Results: The authors found 5 studies in which the investigators addressed the incidence of open contacts after implant restorations are inserted next to teeth. Results from these studies indicated that an interproximal gap developed 34% to 66% of the time after an implant restoration was inserted next to a natural tooth. This event occurred as early as 3 months after prosthetic rehabilitation, usually on the mesial aspect of a restoration. Conclusions: The occurrence of an interproximal separation next to an implant restoration was greater than anticipated. It appears that force vectors cause tooth movement and an implant functions like an ankylosed tooth. Practical implications: Clinicians should inform patients of the potential to develop interproximal gaps adjacent to implant restorations, which may require repair or replacement of implant crowns or rehabilitation of adjacent teeth. Furthermore, steps should be taken to check the continuity of the arch periodically. If the clinician detects an open contact, it is prudent to monitor for signs or symptoms of pathosis so that prosthetic repair of the gap can be initiated, if needed. These problems could add to treatment costs and decrease overall patient satisfaction related to implant treatment.
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Open contacts adjacent to dental implant
Etiology, incidence, consequences, and correction
Gary Greenstein, DDS, MS; Joseph Carpentieri, DDS;
John Cavallaro, DDS
Development of an open contact between a
restored dental implant and a contiguous
tooth, where initially there was a rm prox-
imal contact, occurs more often than
expected (Figures 1and 2).
An interproximal gap
can result in a food trap, caries, and periodontal issues
and precipitate the need for prosthetic repairs.
These untoward consequences are disconcerting for
the patient and clinician.
Occlusal forces are transmitted via contact areas,
and mesial migration compensates for proximal tooth
wear, thereby maintaining intra-arch continuity.
Failure to maintain a rm contact after an implant
restoration is placed often happens on the mesial aspect
of the crown, but it can occur distally (Table).
open contact in an adult dentition adjacent to an
implant restoration is usually due to physiological
mesial drifting of teeth while the implant remains sta-
In this article, we address the etiology,
incidence, consequences, and repair of open contacts
between dental implant restorations and adjacent nat-
ural teeth.
There are 4primary forces that inuence the dentitions
arrangement: tongue and lips, personal behavior (for
example, habits) or orthodontic appliances, periodontal
membrane, and occlusal forces.
The last factor pro-
vides the major force vector associated with physio-
logical tooth migration.
The main muscles of mastication involved with jaw
closure are the medial pterygoid, masseter, superior
division of the lateral pterygoid, and temporalis
Dr. Greenstein is a clinical professor, College of Dental Medicine, Columbia University, New York, NY, and maintains a private practice in
surgical implantology and periodontics in Freehold, NJ. Address correspondence to Dr. Greenstein at 900 W. Main St., Freehold, NJ 07728,
Dr. Carpentieri is a clinical assistant professor, College of Dental Medicine, Columbia University, New York, NY, and maintains a private practice
in surgical implantology and prosthodontics in White Plains, NY.
Dr. Cavallaro is a clinical professor, College of Dental Medicine, Columbia University, New York, NY, and maintains a private practice in surgical
implantology and prosthodontics in Brooklyn, NY.
Copyright ª2015 American Dental Association. All rights reserved.
Background. The aim of this investigation was to evaluate
the potential causes, clinical signicance, and treatment of
open contacts between dental implant restorations and
adjacent natural teeth.
Types of Studies Reviewed. The authors searched the
dental literature for clinical trials in humans that addressed
the incidence of open contacts that develop after implant
restorations are placed next to teeth.
Results. The authors found 5 studies in which the in-
vestigators addressed the incidence of open contacts after
implant restorations are inserted next to teeth. Results from
these studies indicated that an interproximal gap developed
34% to 66% of the time after an implant restoration was
inserted next to a natural tooth. This event occurred as early
as 3 months after prosthetic rehabilitation, usually on the
mesial aspect of a restoration.
Conclusions. The occurrence of an interproximal sepa-
ration next to an implant restoration was greater than
anticipated. It appears that force vectors cause tooth move-
ment and an implant functions like an ankylosed tooth.
Practical Implications. Clinicians should inform pa-
tients of the potential to develop interproximal gaps adjacent
to implant restorations, which may require repair or
replacement of implant crowns or rehabilitation of adjacent
teeth. Furthermore, steps should be taken to check the
continuity of the arch periodically. If the clinician detects an
open contact, it is prudent to monitor for signs or symptoms
of pathosis so that prosthetic repair of the gap can be initi-
ated, if needed. These problems could add to treatment costs
and decrease overall patient satisfaction related to implant
Key Words. Implants; restorative dentistry; operative.
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On mandibular closure, forces created by
these muscles are directed in different directions by the
teeths inclined planes. The forward vector is referred
to as the anterior component of force (ACF), and it drives
teeth mesially.
There also is a force that pushes teeth
distally, but the mesial vector is 5times stronger than
the posterior force.
The strength of the ACF increases
proportionally to the magnitude of the bite force.
In 1923, Stallard
suggested that the arc of mandibular
closure caused an ACF on mandibular posterior teeth
that was transmitted via interproximal contacts between
the teeth and that this vector drove teeth mesially as
the contact points wore because of friction. Subse-
quently, Conroy
subjected all the teeth individually
in a mandibular quadrant to a controlled force (a custom
bite force transducer was fabricated and connected to a
strain indicator) and assessed the magnitude of the ACF.
He noted that the ACF was transmitted via the inter-
proximal contacts and that its strength decreased with
increased distance from the posterior teeth. In addition,
he also conrmed that there was a posterior component
of force.
Arrangement of interproximal interfaces among
human teeth. The size and location of contact areas vary
with age, tooth position, biting force, and crowding of
The contour of the contact interfaces is pre-
dominantly oval and usually found toward the buccal
aspect of interproximal areas. In the incisal region, their
outline is more vertical than horizontal, and in the
posterior sextants of the arch, the shape of an inter-
proximal contact is more horizontal than vertical.
and colleagues
reported that normally the interprox-
imal interface with or without wear decreases in size
from molars to incisors. They suggested that larger
contact areas are needed in the posterior teeth to resist
attrition where there is increased biting force.
Over time, the morphology of contact areas changes
because of attrition and physiological drifting. The oval
contacts often become kidney shaped. This change is
associated with attening of the contact area, which
creates room for the dentition to move mesially. To
reduce this change, Sarig and colleagues
enlarging the interproximal interfaces of restorations
to increase tooth position stability.
From another perspective, the contact area between a
tooth and an implant restoration needs to be modied
after an extraction. Tooth removal results in reduction of
the interdental tissue volume because of shrinkage of the
papilla and bone loss between the tooth and a future
implant restoration. To compensate for a larger embra-
sure or concave shape of an adjacent tooth, the clinician
often needs to use a longer, broader, wider contact in an
occlusogingival dimension.
Reasons for premature loss of contact between
teeth. Intact contact areas prevent tooth migration, allow
dissipation of ACF, and avoid food impaction. Prema-
ture loss of interproximal contacts can occur because of a
variety of factors: caries, early loss of a tooth, inauspi-
cious sequence of eruption, ankylosed teeth, congenital
issues, and trauma.
Loss or alteration of contact areas
can result in interproximal black triangles, food impac-
tion, periodontal problems (such as loss of clinical
attachment, gingival inammation, or reduction of
interproximal bone), and misalignment of teeth.
Figure 1. Radiograph showing delivery of an implant-supported resto-
ration at site no. 30 on November 29, 2010. A broad, wide contact was
conrmed clinically with oss.
Figure 2. Radiograph showing open contact that developed approxi-
mately 1 year after restoration insertion (November 2, 2011) on the
mesial aspect of the implant restoration at site no. 30. No interdental
pathosis was present.
ABBREVIATION KEY. ACF: Anterior component of force.
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Craniofacial growth: a factor for loss of interproximal
contact between teeth. Besides the ACF, adult craniofacial
growth can alter tooth positions.
Historically, Odman
and colleagues
demonstrated that dental implants func-
tion like ankylosed teeth and do not move with additional
jaw growth. Thus, implants usually are not inserted in
patients who are still growing. With respect to adults,
Daftary and colleagues
reported that uncommonly there
is craniofacial growth in some people beyond adulthood.
This growth can result in occlusal alterations. Subtle facial
growth may occur mesially, buccally, and vertically.
Others also have discussed how facial growth after
adulthood can affect the position of teeth.
We searched the dental literature for human studies in
which the investigators addressed the incidence of open
contacts that develop after implant restorations are
inserted next to natural teeth. In this review, we included
all detected clinical trials in which the investigators
described how they assessed the size of open contacts
and dened the length of the monitoring period. We
found 5investigations. Investigators in 1study evaluated
only 3contact points in 1patient; the other investigations
had 28 to 105 patients (Table).
We conducted the
following searches on PubMed: proximal contact loss
adjacent to implant prostheses (2of 6articles included),
loss of interproximal contact adjacent to implant pros-
theses (2of 3articles included), migration of teeth
because of occlusal forces (1of 36 articles included),
and implant prostheses and adjacent tooth migration
(2of 12 articles included).
The table
lists how often we found reports of open
contacts adjacent to restored implant restorations in
different studies. Byun and colleagues
between development of open contacts (oss passes be-
tween teeth unimpeded) and creation of loose contacts
(oss encounters weak resistance). They reported open
contacts at 38% of assessed sites and loose contacts at
20% of the proximal surfaces monitored over a mean
57-month period (range, 3-156 months). They found
the rst open contact 8months after a restoration was
inserted. Koori and colleagues
recorded an increased
incidence of interproximal gaps (43% of study popula-
tion) over 1to 123 months. Wei and colleagues
mented a larger occurrence of open proximal contacts
(58%), and they occurred within a short period (up to
2.2years). They noted the rst open contact 3months
after crown insertion. In a multipatient study, Wong and
reported the largest incidence of open con-
tacts (65%) during a monitoring period of 0.5to 12 years.
They also found that the amount of open contacts was
similar among prostheses that were screw or cement
With increased time, the size of the space between
teeth and an implant restoration may enlarge,
and the
number of open contacts increased with the passage of
The prevalence of interproximal open contacts varied
between studies.
Factors that could contribute to
different ndings are patient age, different study pop-
ulations, types of adjacent restorations, occlusal forces,
Percentage of restored dental implants manifesting open proximal contact areas
adjacent to natural teeth.
Wei and
58 (32/55) 28 55 58 (32/55)
strip Up to 2.2 y
Koori and
43 (80/186) 105 186 52 (73/141) 16 (7/45) 50-
m strip Range, 1 to 123 mo
Wat and
66 (2/3) 1 3 67 (2/3) Not assessed Dental oss 2 y
Byun and
34 open
20 loose
94 191 38 (51/134) 25 (14/57) Dental oss Mean, 57 mo
(range, 3-156 mo)
Wong and
65 (43/66) 45 66 65 (43/66) Not assessed 38-
m Toffelmire
matrix bands
Mean, 3.9 y
(range, 0.5-12 y)
* Different devices were used to assess for the presence of open contacts.
The authors did not clearly state whether open proximal contacts occurred mesially or distally, so we interpreted the data to indicate that it occurred
m: Micrometer.
§ Floss could pass through, but there was a weaker contact than originally determined. These data were from part of the group listed: 94 patients, 191
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opposing dentition, monitoring time, and the methods
used to assess the integrity of the interproximal areas.
Mesial versus distal development of open contacts.
Byun and colleagues
reported that mesial contact
areas of implant restorations next to a natural tooth
manifested a gap more often than did distal aspects.
They found 38%(51 of 134) of the mesial contacts opened
versus 25%(14 of 57) of the distal contacts (Table).
nding was less than that observed by Koori and col-
who reported 52%(73 of 141) of the mesial and
16%(7of 45) of the distal contacts were open by the end
of the assessment period (Table).
Koori and colleagues
also indicated that loss of
contact occurred more frequently in the mandible than
the maxilla. The reason for this nding is unclear. In
addition, they demonstrated that more migration of teeth
was seen when the opposing dentition was composed of
natural teeth rather than a partial or full denture because
natural teeth generate greater occlusal forces.
the investigators in the studies we assessed used different
methodologies to evaluate the tightness of contact areas
Investigators reported different amounts of actual tooth
migration, which could be affected by the duration of
the assessment time, bite force, and so on. By age 40
years, the ACF results in 0.5centimeters (5millimeters)
of mesial migration of teeth.
These alterations oc-
curred gradually, with periods of activity and remission.
In addition, as teeth moved mesially, the alveolar bone
was altered. Bone resorption occurred on the mesial
aspect because of pressure, and bundle bone formed
on the distal surfaces of teeth because of tension.
However, among Swedish adults, investigators found
a smaller proximal wear rate (1mm per arch over
Carter and McNamara
noted a slightly
larger wear rate in people aged 17 to 48 years. Among
males, the mandibular arch perimeter was reduced
2.4mm, and in the maxilla it decreased 1.86 mm. Fe-
males demonstrated an alteration of 1.76 mm in the
mandible and 2.06 mm in the maxilla. Carter and
concluded that changes over years usually
were not clinically signicant because the adjustment
of a full-cusp Angle Class II molar relationship is
approximately 5mm.
Other factors also can inuence mesial migration of
teeth. Wei and colleagues
suggested that high occlusal
forces on teeth adjacent to an implant restoration could
affect the degree of mesial migration. In addition, Koori
and colleagues
stated that age, condition of the opposing
dentition, vitality of adjacent teeth, and splinting of the
adjacent teeth may affect the rate of proximal contact
loss of a xed dental prosthesis adjacent to an implant
Open contacts can have negative effects on the dentition:
food impaction, caries, migration of teeth, periodontal
issues, and additional prosthetic repairs. Several authors
stated that subsequent to developing open contacts, pa-
tients experienced trapping food.
This trapped food
can result in an increased caries rate (Figures 3and 4).
With respect to developing periodontal issues, Byun and
reported no increased incidence of inam-
matory peri-implant problems associated with open
contacts, whereas Koori and colleagues
described a
greater amount of clinical attachment loss and deeper
probing depths. Others noted adverse affects with respect
to periodontal issues when there were open contacts
between teeth.
Different ndings concerning peri-
odontal health or caries could be attributed to the level
of personal and professional maintenance that was per-
formed and the duration that sites were monitored.
Detection of an open contact area between an implant
restoration and an adjacent tooth may not lead to
negative consequences. Therefore, a clinician should
consider the risk-benet ratio of only monitoring such
sites. It may be prudent to eliminate an open contact area
to preclude potential problems, such as root caries that
can result in tooth loss. However, some patients or cli-
nicians may elect to monitor these situations. In these
circumstances, patient compliance with respect to being
assessed periodically is important. If a decision is made
to close an open contact, the clinician must choose to
modify or replace the implant crown or restore the
adjacent tooth.
The average movement of molars during mastication in
the horizontal plane is 56 to 75 micrometers and in the
vertical plane is 28
In contrast, dental implants
demonstrated 5
m in the vertical plane and 12 to 66
in the horizontal plane.
Mesial drifting is not found
with respect to dental implants,
which makes them
analogous to ankylosed teeth. However, it is hypotheti-
cally possible that an open contact could develop be-
tween implants because of facial growth.
After 2years, Wat and colleagues
noted 0.5-mm
gaps had developed between some restored implants
(mesial aspect) and adjacent teeth. They removed the
affected prostheses and made a new working impression.
They added porcelain to the mesial aspect of the dental
implants to reestablish proximal contacts. In this
regard, there are 2major issues that require consider-
ation concerning implant crown fabrication: selecting
a screw- versus a cement-retained restoration and choice
of the restorative material. Selection of a screw- or a
cement-retained restoration should provide retrievability
to facilitate repair of an open contact. Thus, it would be
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benecial if cement-retained crowns were inserted with a
temporary luting agent. With respect to the restorative
format, it will be based on several factors: the clinicians
preference, 3-dimensional location of the implant (posi-
tion, depth, and angulation), and restorative space
measured from the implant platform to the opposing
arch. Minimally, approximately 5mm of vertical space is
needed for a screw-retained crown and approximately
7mm for a cement-retained restoration.
When screw-
retained restorations are used, implants should be placed
as parallel as possible to the adjacent surfaces because
screw-retained prostheses need a line of draw (that is,
path of insertion) that allows crowns to be fabricated
with contacts of proper shape and size.
With respect to selecting a restorative material to
fabricate the implant crown, there are several options:
porcelain fused to metal or porcelain fused to zirconia
with feldspathic ceramic, lithium disilicate glass ceramic
(used with computer-aided design and computer-aided
manufacturing or press techniques), or full zirconia
The choice of the material is an im-
portant clinical decision because of differences in each
material (such as esthetics, fracture resistance, and cost)
and their ability to be modied. When implant restora-
tions are removed, ceramics can be reapplied to restore
the contact area for both the porcelain-fused-to-metal
and lithium disilicate crowns. Similarly, zirconia
monolithic (full-contour zirconia) or bilaminar crowns
(zirconia copings layered with feldspathic porcelain)
can undergo additive correction as long as they can be
retrieved from the mouth. Ultimately, the decision to
modify or replace an existing restoration to close an open
space needs to be made with respect to the following
factors: ease of retrievability, the choice of materials,
nances, esthetics, and the size and predictability of the
potential modication, as well as the expertise of the
laboratory technician.
advocated occlusal adjustment to reverse the
development of open contacts between natural teeth
and implants if the open contact develops distal to an
implant. However, his technique cannot be used uni-
versally because most open contacts develop on the
mesial aspect of an implant and his technique applies to
specic situations in which the implant would have to be
next to the last tooth in the arch.
Occlusal forces can have a detrimental effect on natural
teeth and restorations on teeth or implants, particularly
in patients with bruxism. An easy technique to preserve
tooth patterns and porcelain and to relieve masticatory
stress is to fabricate a retainer or night guard.
Conceptually, use of a retainer should decrease attrition
of tooth contacts and reduce open contacts. However,
this outcome has not been documented in the
The investigations in which the authors assessed the
incidence of open contacts were observational studies.
They were not experimental or controlled studies, and the
authors did not investigate any type of therapy that may
improve outcomes.
The investigators assessed partic-
ular populations of patients over time; therefore, the
studies are considered longitudinal cohort investigations.
Figure 3. Radiograph showing open contact still present at tooth no. 30
mesial (November 4, 2014), but now there is extensive caries on distal
aspect of tooth no. 29, which precipitated the need for a full-coverage
restoration on tooth no. 29.
Figure 4. Radiograph illustrating an open contact on the mesial of
the implant at site no. 31. Subsequently, caries developed on the distal
of tooth no. 30 due to food impaction, and tooth no. 30 needed to be
replaced with an implant.
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Prospective observational studies are conducted to collect
descriptive information, such as the incidence of open
contacts adjacent to dental implants, and to assess asso-
ciations with respect to causes of a problem. However,
confounding variables exist that limit data interpretation.
For instance, in all 5articles in which the authors
addressed the incidence of open contacts,
other quad-
rants without implants were not used as control groups;
therefore, we do not precisely know whether the inci-
dence of open contacts was statistically signicantly
greater adjacent to implants than when an implant was
not placed. This information would facilitate calculation
of the absolute and relative risks of developing an open
contact with or without implant placement.
The available data indicate a high incidence of open
contacts developing subsequent to insertion of implant
restorations adjacent to natural teeth. We have noticed
this phenomenon but not at the level of occurrence re-
ported in the table.
As previously listed, possible ex-
planations for dissimilar ndings include unlike study
populations, disparate methods of assessing contact
tightness, duration of monitoring, different opposing
dentitions, biting force, prosthesis design, and bucco-
lingual and occlusogingival dimensions of restoration
contact areas. Another factor that could account for
discrepancies between study populations is the use of
different statistical methods. For example, Byun and
used a generalized estimating equation so
that multiple sites could be considered from each patient,
whereas others did not address this issue.
It appears
that they had multiple sites per patient, but they did not
account for a persons individual biological makeup.
Despite our critical examination of the methods and
material in the addressed studies, it was not possible to
identify precisely why the reported frequency of open
seemed greater than that in our experiences.
Contrastingly, it could mean that we might need to
quantify the occurrence of open contacts in our private
practices to validate or refute these ndings. Also, some
of the open contacts recorded over time in the reviewed
studies may have been present at the time of prosthesis
placement. Regardless of the precise incidence of open
contacts, these phenomena deserve additional attention
from clinicians.
One additional point of information: the question
could be asked as to why a tooth mesial to an implant
would move anteriorly, because forces are not being
transmitted via a contact point on the distal of the tooth
where the implant remains motionless. The answer is
that continued movement mesially is due to occlusal
vector forces provided by the opposing dentition.
Development of open contacts generally does not occur
between natural teeth because of physiological drift,
the nding that this occurs among patients with implants
indicates that there is something more than mesial
migration occurring. The probable reason that an open
contact occurs is that an implant is ankylosedand
cannot shift like the other teeth.
The precise etiology of an open contact adjacent to an
implant is unclear; it may be due to the ACF, or it may be
multifactorial and related to changes in occlusion.
this regard, physiological migration does not explain the
occurrence of open distal contacts adjacent to implant
The data indicate that open contacts occur more often
than expected between restored implants and natural
teeth, which creates a dilemma for restorative practi-
tioners. Accordingly, clinicians should monitor patients
to determine whether they are developing open contacts.
If this occurs, they may require modication of existing
implant restorations or adjacent teeth. Implant restora-
tions should be retrievable so that contact points can be
restored as needed.
Furthermore, retainers may help
reduce the incidence of open contacts between restored
implants and teeth; however, as indicated, there are no
data in the literature addressing this specic issue. Koori
Suggested guidelines for management of open contacts adjacent to an implant
The possibility of future open contacts should be communicated to patients before treatment, and this information should be included in a
medicolegal consent form.
Retrievability of implant restorations is strongly recommended because loss of interproximal contact is fairly common.
Before impression procedures for implant restorations, modify both adjacent contacts with minor recontouring so they are atter in prole and
rounded, with minor undercuts and rough edges removed.
If there is an open contact with no food impaction, provide no treatment and carefully monitor patient compliance.
If there is an open contact with food impaction without pathosis, the rst choice is modication of the implant restoration; the second choice is
restoring the adjacent tooth.
If there is an open contact with food impaction and caries, modify the adjacent tooth with a conservative restoration or a new full-coverage
restoration to address the caries. If there is a periodontal or peri-implant problem, address it.
Eliminate open contact areas to preclude potential problems, especially in patients with high caries rates or history of periodontitis.
For maintenance and monitoring, use a peri-implant maintenance protocol (3 to 6 months), observe contacts surrounding implants, and reexamine
occlusion in the area of the implant restoration.
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and colleagues
advised that clinicians should include in
their informed consent statements comments advising
patients that development of open contacts adjacent to
implant restoration is an unpredictable event and that its
occurrence may dictate the need for prosthetic repair of
the contact area. As a nal thought, there are no precise
guidelines with respect to the management of an open
contact associated with implant restorations; however,
closing the gap is an approach that reduces potential
complications. The box lists suggested guidelines for
management of open contacts between an implant and
an adjacent tooth. n
Disclosure. Dr. Carpentieri is a consultant and speaker for Zimmer
Biomet. Dr. Cavallaro is a consultant and speaker for Implant Direct In-
ternational. Dr. Greenstein did not report any disclosures.
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... 74 The contact area usually shows flattening and transformation from oval to kidney shape. 75 When a natural tooth is substituted by an implant, tissue shrinkage might require a large contact area in the occlusogingival dimension. 75 Given that implants cannot follow any developmental change, interproximal contact loss may occur. ...
... 75 When a natural tooth is substituted by an implant, tissue shrinkage might require a large contact area in the occlusogingival dimension. 75 Given that implants cannot follow any developmental change, interproximal contact loss may occur. 76 Apart from ACF, potential implant infraocclusion changes the relationship between implant prosthesis and adjacent teeth. ...
... 43 Even if a cemented restoration is delivered, it should be cemented with provisional cements. 77 Material selection is a clinical decision directly connected with cost, esthetics, and possible modifications, 75 as the chance of chipping may be increased by an inappropriate ceramic chosen for contour alterations. 98 Recent studies have shown that composite resin adhesion on silica-based and zirconia surfaces is feasible, 99,100 providing clinicians with the option of chairside repairs. ...
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Objective: To determine the effect of lifetime maxillofacial changes on dental implants placed in adults, analyze the clinical implications of these changes, identify prognostic factors, and offer possible solutions. Overview: The relationship between implant placement and maxillofacial changes, occurring during not only the active growth period but also the entire span of adulthood, has not been extensively examined. Vertical differences between implants and adjacent teeth due to the ankylotic behavior of the former might be observed at any age and endanger restoration biologically, functionally, and esthetically. Regarding interproximal contacts, firm contact loss may occur within a few months after restoration, resulting in food impaction. Many prognostic factors have been reported, but most do not exhibit a statistically significant association with implant infraocclusion and interproximal contact loss. Incorporation of alternative solutions, accurate treatment planning, strict recall protocols, and retrievability of implant-supported restorations can facilitate efficient management of complications. Conclusion: Maxillomandibular changes throughout adulthood may lead to complications such as implant infraocclusion and interproximal contact loss. Rehabilitation of edentulism should be characterized by well-designed and flexible treatment plans to resolve long-term complications efficiently. Further long-term clinical studies are needed to identify other risk factors. Clinical significance: Treatment plans for implant therapy should be reconsidered for adults. Careful patient monitoring and early intervention are essential for securing treatment outcomes.
... 7 As occlusal forces are transferred through contact areas, the proximal aspects can visibly wear, and in order to maintain intra-arch continuity, teeth tend to migrate, moving mesially. 8 Implants do not follow this drift, and this might cause the opening of the mesial contact point, as it is usually reported that PCL is more prevalent at the mesial aspect of the implant restoration. 9,10 Other factors (such as gender, age, and splinting of the adjacent teeth) 11,12 have been proposed as linked to PCL, but no consensus has been reached yet. ...
... PCL between implant restoration and a contiguous tooth is an event that occurs more often than expected (Figs 1 to 3). 8 In the present retrospective study, the statistical analysis showed that the overall prevalence of PCL was 51% (77% on the mesial surface and 68% in the mandible) and that mild resistance was felt in 27% of contact points. These results are in line with what is reported in the literature: Failure to maintain proximal contact is more frequently reported on the mesial aspect of the implant restoration (Fig 2). ...
... Others also have discussed how facial growth after adulthood can affect the position of teeth. 8 Furthermore, PCL in the present study was more frequently recorded in the mandible and on posterior implant restorations (Figs 1 and 3), similarly to results reported by French et al. 16 This validates the hypothesis that the higher prevalence of mandibular PCL is caused by the tendency of mandibular teeth to drift mesially during adulthood. 17 In the present study, the PCL rate increased from 8% at 5 years to 16% at 7 years. ...
Restoring the proximal contacts is important for a restoration's long-term success. A frequently observed late complication of implant restoration is proximal contact loss. At present, there is a lack of sufficient research for determining the prevalence of proximal contact loss and for identifying the causative factors. The purpose of this clinical retrospective study was to evaluate the prevalence of proximal contact loss between implant restorations and adjacent teeth and to identify the causative factors. Partially edentulous patients who had received single crowns or fixed dental prostheses on implants were selected; the rehabilitations were metal-ceramic or all-ceramic, screw- or cement-retained. The primary study outcome was clinical evaluation of mesial and distal proximal contact tightness. The secondary outcome was evaluation of patient awareness of proximal contact loss, food impaction, and occurrence of biologic complications. In total, 237 single crowns and 83 fixed partial dentures were assessed. A multivariate logistic regression model was adopted. The overall prevalence of proximal contact loss was 51%. Among the patients with proximal contact loss, 107 (65%) were aware of its presence, while 58 (35%) reported food impaction. Within the limits of the present study, proximal contact loss between implant prostheses and adjacent teeth can be considered a frequent event, even at a 10-year follow-up, that should be carefully considered and monitored by patients and operators.
... Implant dentistry has become the mainstream approach for replacing missing teeth overcoming the common problems usually associated with partial dentures and bridges, such as discomfort, caries in abutment teeth or accumulation of plaque which could threaten the pulpal and periodontal health of adjacent teeth if no preventive approach is given (den Hartog et al., 2008). However, concerns in teeth adjacent to implants are also reported, mainly related to proximal decay and periodontal disease, which are attributed to the lack of long-term stability of interproximal contact (Greenstein et al., 2016;Koori et al., 2010;Pang et al., 2017;Ren et al., 2016;Varthis et al., 2016) and/or narrow implant platforms (Smith et al., 2020). Natural teeth may be subject to some physiologic movement whereas the implant is ankylosed, which, over time, results in the loss of interproximal contact between both structures. ...
... Natural teeth may be subject to some physiologic movement whereas the implant is ankylosed, which, over time, results in the loss of interproximal contact between both structures. Alongside with a narrow implant platform, such conditions make it difficult to properly clean, favouring plaque retention and food trapping at those interproximal surface, resulting in a higher susceptibility of enamel tissue to demineralization and decay or even periodontal disease (Greenstein et al., 2016;Koori et al., 2010;Pang et al., 2017;Ren et al., 2016;Varthis et al., 2016). ...
... In the present study, the prevalence of restorative procedures on teeth adjacent to natural teeth-supported crowns was 70.5% (Table 3). It can be inferred that the higher frequencies of restorations and root canal treatments in both groups of teeth adjacent to implant-and to natural teeth-supported crowns are the result of the interplay of various reasons, such as the patients diet, loss of interproximal contacts (Greenstein et al., 2016;Koori et al., 2010;Pang et al., 2017;Ren et al., 2016;Varthis et al., 2016), width of interproximal point of contact (Smith et al., 2020) and poorly contoured crowns which tend to deform the gingival embrasure space making oral hygiene procedures and inter-dental cleaning difficult (Reitemeier et al., 2002). ...
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Aim: To describe the prevalence of periapical lesions, root canal treatments and coronal restorations on teeth adjacent to either implant- or natural tooth-supported crowns using cone-beam computed tomography (CBCT) assessment compared to nonadjacent teeth. Methodology: A total of 1249 CBCT volumes were screened by five pre-calibrated observers in 11 health centres. A step-by-step screening protocol was implemented and reviewed every 3 months, and mandatory setting characteristics were established for all CBCT scans using dedicated visualization software. Intra- and inter-rater reliability tests were conducted. The prevalence of periapical lesions, root canal treatments and coronal restorations was recorded on both teeth adjacent and nonadjacent to implant- (predictor 1) or natural tooth-supported crowns (predictor 2). A binary logistic model (Generalizing Estimating Equations test) was used to verify whether the prevalence of periapical lesion, root canal filling and the tooth restorative status are altered when the assessed tooth is adjacent or not to an implant-supported crown (predictor 1); or to a natural tooth-supported crown (predictor 2). Odds ratio and confidence intervals for the dependent variables at both predictors were obtained. The significance level was set at .05. Results: A global sample of 22 899 teeth was included. Compared to nonadjacent teeth, the prevalence of periapical lesion, root canals treatments and restorative procedures when adjacent to implant-supported crowns was 10.7%, 19.6% and 22.9% higher, respectively, and when adjacent to tooth-supported crowns was 19.3%, 35.6% and 37.4% higher respectively. These results were significant only for variables root canal filling and coronal restoration (p < .0001). Odds ratio to present root canal treatment is 2.57 times higher (CI 1.95-3.39, p = .0001) when the tooth is adjacent to implant-supported crown and 4.39 times (CI 3.49-5.53, p = .0001) when adjacent to tooth-supported crown, whilst for restorative procedure, the odds are, respectively, 1.63 (CI 1.29-2.06, p = .0001) and 2.30 (CI 1.92-2.76, p = .0001). Conclusions: Teeth adjacent to both implant- and natural tooth-supported crowns were associated with a higher frequency of root canal filling and coronal restorations.
... Some studies have mentioned that ICL causes inflammation around the implant, resulting in marginal bone loss and implant failure. 14,18 Considering the importance of the issue, this umbrella review investigates the incidence of ICL between implant prostheses and nearby natural teeth. In this study, the null hypotheses were that "there is no correlation between implant-supported prostheses and natural teeth adjacent to the ICL" and "there is no significant difference between the sex of the individual and the ICL position (mesial/distal, anterior/posterior, and maxilla/mandible)." ...
... After carefully studying the titles/abstracts of the articles, 12 articles met the eligibility criteria. Seven of them [15][16][17][22][23][24][25] were excluded due to the reasons indicated in ►Table 2, and a total of five studies were selected eventually, 14 ...
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Contact loss between the implant prosthesis and adjacent natural teeth is a clinical complication whose overall prevalence is uncertain. Therefore, the main purpose of this umbrella study was to evaluate the extent of contact loss between implant prostheses and adjacent natural teeth. Electronic database of MEDLINE/PubMed, Cochrane, and Google Scholar was searched until August 2021 without considering language restrictions and according to Preferred Report Items for Systematic and Meta-Analysis guidelines (preferential reporting items for systematic review and meta-analysis). Inclusion criteria were systematic/meta-analysis review articles related to contact loss between implant prostheses and adjacent natural teeth. Inclusion criteria and risk of bias for the selected systematic/meta-analysis review studies were assessed by two or three qualified researchers, and the fourth researcher was used to resolve the ambiguities. From 43 eligible articles, five systematic/meta-analysis review studies were selected for this study. Important information such as the range of contact points, the prevalence, and the location of the contact loss was extracted. Three research studies had a low risk of bias and were considered clinical evidence. Analysis of low-risk studies showed that the superiority of open contact loss was excessive. Prevalence of proximal contact loss was more in mesial contact, especially in the mandibular arch. No significant differences were reported in sex or between the posterior and anterior regions.
... When PCL occurs, the prosthesis must establish new contacts with the adjacent teeth, with the modification of either the teeth or prosthesis [13]. A retrievable prosthesis can be transferred to the dental laboratory, where porcelain is added to the proximal surface for closing the clearance. ...
... These observations indicate that food impaction is closely related to PCL. Nonetheless, food impaction can create problems including the migration of teeth, dental caries, and periodontal issues [13]. ...
Full-text available
BACKGROUND Proximal contact loss (PCL) is very common between implant-fixed prostheses (IFPs) and adjacent teeth and leads to a high incidence of food impaction. Our aim was to determine if the mesio-distal adjustable (MDA) crown prostheses introduced in this study could easily establish new contacts intraorally without the intervention of prostheses retrieval. MATERIAL AND METHODS The MDA crown requires casting in the inlay framework at the proximal contact area. If PCL occurred, the resin in the inlay framework could be easily removed and refilled chairside. This single-center prospective study aimed to investigate the use of a resin inlay dental implant-fixed prosthesis for the closing proximal contact loss in 93 patients who were recruited from April 2017 to December 2017. Four patients dropped out during the 3-year follow-up; therefore, 89 patients were included. The effect of this technique was assessed by the implant mucosal status and follow-up investigations of food impaction. RESULTS PCL occurred in 29.21% (26 prostheses) of the IFPs. The PCL rate at the mesial contact surfaces (n=24, 26.97%) was significantly higher than that at the distal contact surfaces (n=5, 8.33%) (P<0.01); however, the incidence of PCL was greater at adjacent teeth with significant bone resorption (P=0.00). After readjusting the resin inlay and closing the clearance, implant mucosal status and food impaction were significantly reduced (P<0.01). CONCLUSIONS The findings of this study showed that use of the MDA crown for closing PCL was time-saving and effective with satisfactory results at 3-year follow-up.
... 11 The possibility of mesial tipping or drifting of adjacent teeth may cause a significant opening in the mesial contact point. 12 Biofunctional aspects could be effective in altering tooth positions so that changes in the chewing pattern or the contact points lead to alterations in proximal contacts. 13 PCL affects periodontal health, and loss of the contact points between a tooth-supported fixed restoration and the adjacent teeth is associated with food impaction. ...
Background. This systematic review and meta-analysis investigated the prevalence of proximal contact loss and its associated factors. Methods. A bibliographic search was conducted in June 2021 with no limitation in the article date or language and updated in January 2022 by hand searching. There was no time limit on the search to retrieve all studies. The search included randomized controlled trials or quasi-experiments, and cross-sectional or cohort studies were included in the absence of these studies. Two authors screened the title and abstract. After evaluating the full texts of selected articles, irrelevant studies and or non-English papers that were impossible to translate were excluded. Disagreements between the re­viewers’ selection process were resolved by debate on the eligibility of studies. Standardized critical appraisal instruments from the Joanna Briggs Institute for different types of studies were used to assess the studies’ quality. Comprehensive Meta-Analysis (CMA) software (Version 2.2; Biostat, Englewood, NJ) was used for data analysis. Results. The proximal contact loss (PCL) frequency was %29. According to the results, the frequencies of PCL for the distal and mesial aspects were %7 and %21, respectively. The meta-analysis results showed that the contact loss events on the mesial aspect were statistically higher than on the distal aspect (P<0.0001). There were no significant differences between other associated factors such as the mandibular or maxillary arch, retention type, opposing dentition, implant type, molar or non-molar, parafunction behaviors, and vitality of adjacent teeth. There was a significant association between bone loss and PCL, and in individuals with bone loss >%50, the proximal contact loss was higher (OR: %95[ 2.43 CI: 4.03‒1.47], P=0.0006). The PCL in the anterior area was lower than in the posterior area (P=0.004). Although the frequency of contact loss in females was higher than in males, this rate was not statistically significant. Conclusion. The PCL on the mesial aspect and the posterior area was high. In individuals with bone loss >%50, the proximal contact loss was higher than in others.
... 69, respectively). In a review, Greenstein et al. showed that after an implant restoration is inserted in adjacent to a natural tooth, an interproximal gap developed 34% to 66% of the time [27]. Their recommendation was to wear an occlusal appliance during sleep in order to decrease the attrition of tooth contacts and reduce the open contacts, although they noted that this outcome has not been documented in the literature. ...
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Aim: The aim of this paper is to perform a retrospective assessment of the clinical performance of the complete oral rehabilitation of patients with bruxism treated with implants and teeth-supported veneered and non-veneered monolithic zirconia restorations with increased occlusal vertical dimension. Methods: In this retrospective follow-up study, 16 bruxer patients, mean age 59.5 ± 14.9 years, were treated with 152 veneered and 229 non-veneered monolithic zirconia and followed for a mean of 58.8 ± 18.8 months (range 1-8 years). The patients were examined clinically and radiographically, annually. Clinical data were extracted from the medical records. In the recall appointments, modified California Dental Association (CDA) criteria were used to evaluate the restorations. Implant and restoration survival and success rates were recorded and analyzed. Results: The cumulative survival rates of implants and restorations were 97.7% and 97.6%, respectively. Nine restorations were replaced: three due to horizontal tooth fractures, two because of implant failure and four had secondary caries. A total of 43 biologic and technical complications were recorded. In the veneered group, the predominant complication was minor veneer chipping (16.4%), which required polishing only (grade 1). In the non-veneered group, the main complication was open proximal contacts between the implant restorations and adjacent teeth (14.5%). Conclusions: The survival rates of restorations and implants in patients with bruxism are excellent, even though veneered zirconia restoration exhibited a high rate of minor veneer chipping, which required polishing only. The biologic complication of fractured single-tooth abutment may occur.
... In a systematic review and meta-analysis, the odds ratio of developing open proximal contacts between implant-supported prostheses and adjacent teeth was found to be 2.46 compared to tooth-supported prostheses [29]. Another review of the literature reported open proximal contacts in 34-66% of cases after the insertion of an implant restoration, which was explained by the exertion of force vectors on the teeth while the implant is ankylosed to the bone [30]. Recently, a systematic review and meta-analysis reported a cumulative 41% rate of loss of proximal contacts [31]. ...
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The aim of this study was to assess retrospectively the survival and success rates of monolithic zirconia restorations supported by teeth and implants in bruxer versus non-bruxer patients. Methods: A total of 15 bruxer and 25 non-bruxer patients attended the recall appointment. The bruxer group (mean age of 61.2 ± 13.3 years and follow-up of 58.7 ± 16.8 months) were treated with 331 monolithic zirconia restorations, while the non-bruxer group, with a comparable mean age and follow-up time, were treated with 306 monolithic zirconia restorations. Clinical data were retrieved from the patients’ files. At the recall appointment, all supporting teeth and implants were examined for biological and technical complications, and the restorations were evaluated using modified California Dental Association (CDA) criteria. Data were statistically analyzed using survival analysis methods. A significance level of p < 0.05 was used. A total of 31 versus 27 biologic and technical complications were recorded in the bruxer and non-bruxer groups, respectively. No significant differences were found between the two groups regarding overall complications and survival rate. Regarding the type of complication, a significantly higher rate of veneered porcelain chipping (p = 0.045) was observed in the bruxer group. With regard to biological complications, the only complications that exhibited a borderline, although not significant, difference were three fractured teeth exclusively in the bruxer group (p = 0.051), which were replaced with implant-supported restorations. Within the limitations of this study, we conclude that there were no significant differences in the overall survival and success rates of the monolithic zirconia restorations in bruxer versus non-bruxer patients, although veneered zirconia restorations and single tooth abutments exhibited a higher rate of complications in the bruxer group.
Background: The prime concern of an implant-supported prosthesis (ISP) is to maintain an optimal proximal contact tightness, which further maintains arch integrity, improves masticatory effectiveness, and minimizes peri-implantitis. Objective: To investigate the loss of proximal contact tightness between single tooth implant-supported prosthesis and the adjacent natural teeth. Methods: Forty patients treated by a single mandibular first molar ISP, aged between 18-50 years were selected. All were randomly allocated in Group I and Group II. Group I, 20 subjects who have received ISP without an insertion of Essix retainer, and Group II patients received an insertion with Essix retainer. The groups were subdivided into Subgroup A, B, and Subgroup C, D, in which A and C are control groups. To measure the tightness at proximal contact points, a digital force analyzer was used. Proximal contact tightness (PCT) was measured immediately after the placement of the prosthesis, 3 months, 6 months, and 1-year follow-up respectively, and the PCT values at end of 1 year were statistically evaluated. Statistical analysis was done, mean and standard deviation was calculated by independent sample t-test wit p< 0.05 as a statistically significant value. Results: In Group I, towards the end of 1 year, 2.09 N (65.5%) and 1.50 N (53.1%) loss of PCT were found on mesial and distal contact areas respectively. In Group II, loss of PCT at mesial contact area was 0.87 N (28.9%) and at distal contact area was 1.77 N (53.3%), which is significantly less compared with the non-usage of Essix retainer (p< 0.05). Conclusion: The usage of Essix retainer, PCT increases especially on the mesial contact area. The frequency of contact loss was decreased. Thus, to minimize the loss of proximal contact the usage of Essix retainer is recommended.
The contribution of biomechanical factors in the formation of proximal contact loss has been observed, but there is little research on the mechanisms by which they contribute. Using finite element analysis, this study aimed to analyse the impact of bone quality on the biomechanical behaviour of a dentition consisting of implant prostheses and adjacent teeth. The occlusal load was applied on the implant/tooth crown. In the mesiodistal direction, the adjacent natural tooth mesially to the implant denture had the tendency for mesial movement, while the distal adjacent natural tooth had the tendency for distal movement. For the supporting bone around the mesial adjacent tooth, the maximum/minimum principal stress and strain values on the mesial side of the bone were higher than those on the distal side of the bone. Stress and strain values on the mesial side of the supporting bone around the distal adjacent tooth were lower than those on the distal side. With decreasing bone density, displacements of teeth and the implant denture, principal stresses and equivalent strains on tooth supporting bone increased. Studies on biomechanical behaviours of a tooth‐implant dentition may provide a deeper understanding of implant‐induced dental adaptive processes such as proximal contact loss.
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PURPOSE: To evaluate the fracture resistance of all-ceramic crowns cemented on titanium and zirconia implant abutments. MATERIAL AND METHODS: Customized implant abutments for maxillary right central incisors made of titanium (Ti) and zirconia (Zr) (n=60, n=30 per group) were fabricated for an internal connection implant system. All-ceramic crowns were fabricated for their corresponding implant abutments using the following systems (n=10 per group): (1) monolithic computer-aided design/computer-assisted manufacture (CAD/CAM) lithium disilicate (MLD); (2) pressed lithium disilicate (PLD); (3) yttrium stabilized tetragonal zirconia polycrystal (YTZP). The frameworks of both PLD and YTZP systems were manually veneered with a fluorapatite-based ceramic. The crowns were adhesively cemented to their implant abutments and loaded to fracture in a universal testing machine (0.5 mm/minute). Data were analyzed using two-way analysis of variance (ANOVA) and Tukey's test (α=0.05). RESULTS: Both the abutment material (P=.0001) and the ceramic crown system (P=.028) significantly affected the results. Interaction terms were not significant (P=.598). Ti-MLD (558.5±35 N) showed the highest mean fracture resistance among all abutment-crown combinations (340.3±62-495.9±53 N) (P<.05). Both MLD and veneered ceramic systems in combination with Ti abutments (558.5±35-495.9±53 N) presented significantly higher values than with Zr abutments (392.9±55-340.3±62 N) (P<.05). MLD crown system showed significantly higher mean fracture resistance compared to manually veneered ones on both Ti and Zr abutments (P<.05). While Ti-MLD and Ti-PLD abutment-crown combinations failed only in the crowns without abutment fractures, Zr-YTZP combination failed exclusively in the abutment without crown fracture. Zr-MLD and Zr-PLD failed predominantly in both the abutment and the crown. Ti-YTZP showed only implant neck distortion. CONCLUSIONS: The highest fracture resistance was obtained with titanium abutments restored with MLD crowns, but the failure type was more favorable with Ti-YTZP combination.
The complexity and labor-intensive nature of making implant-level impressions may inhibit some clinicians from recommending dental implant treatment. This paper describes a simplified impression technique for fabricating anatomical, cement-retained abutments without removing or inserting implant components. Using digitally coded healing abutments, this protocol bridges the gap between traditional impressions and computer-aided abutment manufacturing. Basic logistic considerations are reviewed, as well as other biomechanic and esthetic advantages, that should optimize overall treatment outcomes.
Objectives The aim was to analyze influential factors and effects of proximal contact loss between implant-supported fixed dental prostheses (FDP) and adjacent teeth.Material and methodsNinety-four subjects treated with 135 FDPs supported by 188 implants were included. Degree of proximal contact tightness, food impaction, and periodontal/peri-implant tissue conditions were assessed in 191 proximal embrasures between implant-supported FDPs and adjacent teeth. Potential factors influencing proximal contact loss were estimated with the generalized estimation equation (GEE) procedure.ResultsThirty-four percent of the proximal embrasures between implant-supported FDPs and teeth lost a proximal contact. The proximal contact loss rate continuously increased over the follow-up periods. A longer follow-up period, splinted implants, and mesial aspect of proximal contact were significant factors influencing the proximal contact loss in the univariate GEE analysis, whereas a longer follow-up period was the only significant factor in the multivariate GEE analysis. Food impaction was more frequently reported in the proximal contact loss group than the proximal contact group (odds ratio: 2.2). However, the proximal contact loss did not appear to affect the periodontal/peri-implant tissue conditions.Conclusions Proximal contact loss between implant-supported FDPs and teeth occurred frequently and increased continuously over the follow-up period. The proximal contact loss significantly affected food impaction, but not the periodontal/peri-implant tissue conditions. Proximal contact loss should be carefully monitored during follow-up examinations in relation to food impaction.
The objective of this study was to determine the relationship between the anterior component of occlusal force and malalignment of the mandibular anterior teeth. The anterior component of occlusal force that resulted from axially loading the second molars was measured in 15 subjects with varying degrees of mandibular anterior dental malalignment. Malalignment of the mandibular anterior teeth was found to be related to the magnitude of the anterior component of occlusal force and to the tightness of interproximal contacts in the mandibular posterior segments.
Purpose: The sequence of observations presented is intended to alert the dental profession to complications that may occur when teeth and implants co-exist and subtle adult craniofacial growth occurs. Materials and methods: The authors' observations of partially edentulous implant restorations with more than 20 years of follow-up included some observed changes relative to patients' remaining teeth and jaw structures. These changes, which were not easily explained and appeared to be random deviations from expected implant-restorative stability, conformed with research findings of craniofacial growth continuing into adulthood. The authors identified several distinct areas in which such adult craniofacial growth could potentially influence the relationship of implant restorations to the remaining teeth and jaw structure. Results: Potential esthetic, occlusal, and periodontal ramifications of continued adult craniofacial growth were found to include changes in occlusion, opened contact as a result of teeth migration, and changes in anterior esthetic results. The latter may include labialization of the anterior implant restoration and a progressive discrepancy of the cervical gingival margin of the implant restoration relative to the adjacent teeth. Cases are presented showing poor sequellae of treatment due to growth occurring after the assumption was made that a stable jaw dimension had been reached. While continued adult craniofacial growth sufficient to cause clinical problems is not common, it is also presently not predictable. Conclusion: When changes in tooth position relative to implant restorations secondary to long-term adult growth occur, they can cause problems that are difficult or even impossible to correct. Future research will ideally enable identification of patients at risk for developing such problems.