tooth implant connection with fix partial dentur,prosthetic dentistry

2. Tooth-Implant
Connection:

4. history
 The history of connecting implant to the tooth dates back
 to early 1980s, when there was no implant with antirotational
 feature, and connecting the implant to tooth to prevent
 rotation of the restoration and screw loosening or fracture.
 Although Branemark implant(Noble Biocare, Yorba Linda, Calif),
introduced in 1982, had hex head for aligning the implant during
insertion, because of flat (non-hex) abutment surface, such connection
was still a necessity.

5. history
 In 1984, core-vent (Zimmer Dental, Carlsbad,
Calif) introduced the first antirotation abutment
 In 1986, the first screw-retained abutment was
introduced. Because of lack of antirotational
feature , the screw represented the weakest link
and was prone to failure.

6. history
 After all in 1988 Dr John Beumer of introduced
the first screw- retained abutment with anti-
rotational feature:
 ‘The UCLA abutment’. With this invention,
creation of freestanding implant restoration
 Today connecting the implant to the tooth
always is not a necessity but there are conditions
where such a connection is our first choice or
even an exigency

7. Differences between Dental Implants and Teeth

8. Comparison of Biomechanics of Implants and
Teeth
 Relation of natural teeth with bone tissue; is designated to
minimize the forces which will distribute to crestal bone
with different mechanisms
 Tissue that covers the natural teeth acts as a viscoelastic shock
absorber that lessened the amount of stress which was inbound to
 bone structure in crestal region

9.  Furthermore, direct conduction of implant and the surface
 of bone is not flexible as much as natural teeth. That is
 why an energy formed by occlusal load may not be distributed
 entirely. thus, overloading is fatal
 Resistance of a titanium implant is calculated 10 to 100
 times higher than a tooth. Besides, loading duration and
 magnitude of force have important effects on the stress of
 bone which lay around the teeth. is is due to the fact that,
 periodontal ligament is viscoelastic nature

10.  Mobility of a natural tooth may increase with the occlusal
trauma.
Tooth may become its original occasion, afer eliminating occlusal
 trauma in spite of the size of tooth movement. Mobility of an
 implant may be formed in same way under occlusal trauma.
 Afer elimination of the factor, implant frequently returns
 into its original rigid position. Alternatively, mobility of
 implant may continue, health of surrounding tissues become
 worse, and commonly implant is lost in a short time period

11. rational of Natural Teeth Connection
 splinting decrease in mobility of mobile teeth.
 Splinting of teeth will decrease the complication which
may occur in long term, if contacts in posterior region
are not hindered with prosthesis or skeletally in lateral
movements.
 In addition, connection of natural teeth abutments
decreases the incoming load on each support by
dissipation

12. rationale
 • To gain support from the tooth or implant: As an
example in the patients with bruxism, properioception
 • The absence of other options: Because of systemic, local
 or financial limitations, bone augmentation and insertion of additional implants are
not always possible.
 Cantilever on one implant, implants narrower than 4 mm (type B), or in situations of
moderate-to-severe force factors are not recommended.
 • To preserve a key tooth or teeth with good prognosis.
 • To provide stability against rotational forces.
 • For esthetic reasons: Implants unlike natural teeth always present challenges with
regard to esthetic. Furthermore, retaining the tooth preserves the
 adjacent papillae.

13. The causes of potential problems:
 The virtual problems refer mainly to the difference in
 the tooth and implant supporting mechanisms.PDL
 causes greater movement in the tooth. Lateral movement
 of the teeth is about 56 to 108 m in comparison to 10
 to 50 m in the implant ,apical movement of the tooth is 25 to 100 m and
that
 of the implant is 3 to 5 m. this difference can cause greater stress on the
implant.
 difference in survival rates of the tooth and implant.
 might decay or need endodontic therapy.

14. 6. Advantages and Problems
 (1) Increasing the treatment options for splinting teeth for implants.
 (a) Cases with anatomical restrictions (maxillary sinus, mental
foramen).
 (b) When insufficient bone exists and placement of
 implant is not possible.
 (c) When patient does not agree to have augmentation

15. Advantages
 • Broadened treatment possibilities
 • Reduced cost (reduction of implant numbers)
 • Protective value of properiception
 • Desire to splint a mobile key tooth to an implant
 • Additional support for total load on dentition
 • Reduction of the need for a cantilever
 • Preservation of the papilla adjacent the tooth for
esthetic and phonetic reasons
 • More favorable bone reaction when the bridge
 is connected to both the implant and teeth.

16. Advantages
 Cavicchia reported that problems such as
 loosening and fracture of fixation screws and
 abutments, ceramic fracture and tooth migration
 seem to occur more frequently in free standing
 implants compared to the tooth connected
 restorations. This result can be related to the
 decrease bite force in tooth-implant supported
 prosthesis because of tooth related properioception.

17. Disadvantages
 Potential disadvantages consist of:
 • Technical problems, such as implant or tooth
 fracture, tooth intrusion, cement bond breakdown,
 screw loosening and prosthetic materials fracture.
 • Biological problems, such as peri-implantitis,
 endodontic problems, lose of tooth or implant, caries
 Intrusion of the tooth is one of the most debated
 topics in the literature particularly with
 nonrigid connectors or coping and telescopes with
 provisional cement or with no cement. The
 interesting point is that in one study the number of
 intruded teeth was significantly more in patients with
 intact periodontal support.

18.  The discussed causes of the intrusion consist of:
 • Differential energy dissipation
 • Friction between the matrix and patrix wall in nonrigid c
 • Debris impaction in nonrigid connectors
 • Impaired rebound memory of tooth
 • FDPs flexure
 • Disuse atrophy of PDL
 • Mandibular flexure (average value: 0.9 mm)
 • Transfers of microshock waves to the natural tooth

19.  Rieder and Parel found that 50% of the intrusions
occurred in the individuals with parafunctional habits,
especially bruxism.
 Srinivasan has a contradictory opinion about this
 reported event. Based on orthodontic references, he
 believes that ‘the forces should be light, continues
 and controlled to bring about intrusion without
 damaging the tooth, in tooth-implant connection it
 is not the case’.

20. potential risks
 A. Overloading:
 depends on occlusal force factors, tooth mobility and the number of other
implants already in the mouth can overload
 the implant and its peripheral bone.
 Based on the literature, load duration appears to have a greater influence than
load intensity on stress distribution in the bone.
 The stress of transitional loads, because of viscoelastic properties of the PDL,
 is better distributed whereas static load causes progressive deformation of the
PDL and, therefore, the tooth would sink into the alveolus; then the bridge would
act as a cantilever on the implant and overstress it.

21. potential risks
 B. Loss of irretrievability (when the screw is loosened or broken).
 C. Progressive bone loss as follows:
 In a study with the follow-up ranging from 1.5 to 15 years, the authors
found a statistically significant difference in marginal bone loss between
the free standing implant prosthesis and TISP yet there
 are controversies about this result. In one study, slight apposition of the
marginal bone was noted around
 the implant in TISP.

22. The available methods
 Rigid connection
 • Some authors believe that It will produce greater marginal bone loss, with
a corresponding increase in probing depth (tooth or implant).
 • Clinicians, who advocate connecting the tooth to the implant rigidly,
accept the differential mobility of the implant and teeth, but they deem
there is sufficient flexibility in the implant to compensate this and allow
sharing of the load.
 • Long-term studies suggest that the tooth and bone implant components
were able to undergo some deformation to compensate for the differences
in the implant and tooth resiliency under functional load.
 achieves better outcomes by avoiding dental intrusion.

23.  Skalak noted that use of rigid connections in
 unfavorable. the main reason of their thought was, implants
 would expose to much more occlusal loads than natural teeth,
 and this may cause tissue atrophy around the natural teeth
 and desimantation problems

24.  • Nonrigid connection
 A. Intermobile elements (IME)
 It has been said that these elements provide flexibility
to compensate for the mobility of the tooth. Uysal
 in 1996 reported that these elements reduced the
 strain up to 60% compared to the rigid internal
elements.In an in vitro study, it was demonstrated
that IME did not contribute to the flexibility of the
system and the bending force was transmitted to
the retaining screw of the implant abutment.

25.  B. Attachments
 It has been mentioned that the attachments reduced
 the level of stresses in the bone, because it breaks
 the stress transfer process and more efficiently
 compensates for dissimilar mobility of the tooth and
 implant but intrusion in 3 to 4% of the cases has
 reported to cause cantilever formation on the implant
 and increase the unfavorable stress values in the
 implant and prosthesis.

27.  Finite element analysis showed stress concentration around
the non-rigid connector.
 Von Oosterwyck, Naert and Nishimura mentioned that
 rigid connection compared to free-standing implants or
nonrigid connections overstress the implants and result in
 greater bone loss around the implant; however, along
 with most of other authors, they expressed their preference
 for rigid connection over nonrigid connectors.

28. Long-term complication, guidelines
 • Pjetursson reported the fracture of the veneer material as the most
common complication that is more frequent in ISP (11.9%) than TISP (7.2%).
He also mentioned that loss of retention was more frequent in TISP (7.3%)
than ISP (5.7%).
 • Bragger demonstrated that technical and biological complications after
10 years were more prevalent in TISP (50%) than ISP (45.5%).
 • Several studies reported higher complications in TISP in comparison to ISP
and attributed them to the risks of tooth complications, like carious lesions,
loss of vitality and periodontal problems

29.  In order to reduce the complications and improve
 TISP performance, some studies proposed useful
 guidelines to follow:
 • The natural tooth should have superior stability
 through long rooted, multirooted, negligible
 mobility, adequate periodontal support or splinting
 to an extra tooth or teeth.
 • The implant should have substantial size and be in
 type I or II quality bone.
 • Nonrigid attachments should be avoided as they
 increase the incidence of tooth intrusion.

30.  in case of inevitable use of these connectors, connect the
 attachment to the implant restoration (between the
 pontic and the implant).
 • The pontic should be of short span.10,27
 • The implant component and retaining screw must
 exhibit some degree of flexibility.
 • Take care to eliminate or minimize lateral forces
 • Consider bruxism to be a risk factor and manage it with an antibruxism splint
 • Use highly retentive cement with superior retentive preparation design on the tooth
 • If telescopic crown or coping are utilized, avoid using temporary or nocement
 • Because of the potential tooth intrusion, consider frequent occlusal adjustment as
an important followup step.

31.  It is possible to say same principles in teeth-implant
connections.
Natural tooth which is splinted rigidly to implant,
must be in retantive form without any mobility.
these 2 simple rules and demand of increasing abutment
numbers as much as possible, must be remembered while
planning teethimplant supported fixed partial dentures

32.  that is why; immobile abutment requirement is
one of the important criterias in connecting
implant to natural teeth in clinical practice .
 Other criteria is, avoiding lateral loads on
abutment while designating a prosthesis. Lateral
movements increase teeth movements while
decrease the movement of implants. Lateral
movements of natural teeth, cause more stresses
than vertical movements
 As such, stress is increased in crestal bone area
with the horizontal forces which affects implant.

33.  Intact tooth has 8–28 𝜇𝜇m physiological vertical movement
while this movement is 0–5 𝜇𝜇m for implant.
Horizontal moves are excessive than vertical ones. Teeth make
moves
 56–108 micron even with small forces like 500 gram (Figure1).
 In such a case, it is possible to get excessive load on implant
biomechanically with the connecting of an implant to its
mesial neighboring .
 Lateral forces increase the amount of stresses on the bone
that is around the implant With conducting to implants. So
that, connecting implants
 to posterior teeth may increase the success in implant-tooth
 supported restorations

34.  e important points that must be taken in account in natural teeth-
implant connection can be summed up with the light of all these
informations, below;
(1) the distance between the natural teeth and implant increases,
rotational movement of implants with vertical and horizontal forces
decreases
 (2) Natural teeth must have low mobility clinically [5].
 (3) If two or more implants are supports, there is pressing stress on the
implant that is nearest to pontic, while 􀄘exion stress will be formed on
the furthest implant to pontic [10].
 (4) When molar teeth are used as a support, they have more resistance
to horizontal rotational movements which can occur on implant
abutment with lateral forces so as to number of root and root surface
area.

35. CONCLUSION
 Although the best option appears to be complete implant-supported prosthesis, there
 are specific conditions in which the dentist should select between connecting the implant
to the tooth in a fixed partial denture or using a removable denture, extraction of
remaining teeth.
 Based on literature reviewed, implant-tooth splinting can be reliable treatment option in
properly selected patients; there is no scientific support for extraction of the teeth to avoid
connecting them to the implant.
 Like every other dental practice, this territory requires
 proper patient selection and complete attention to all the
 details for success. This method has its own advantages,
 disadvantages, risks and complications, but what justifies
 its application is risks- benefit evaluation with attention to
 patient requirements.

36. CONCLUSION
 However, due to limitations of available literature with
 regard to sample sizes, duration of studies, disparity of study
 groups and incoherent study situations, it is extremely
 difficult to compare the available literature and obtain
 absolute conclusion. These same features make more
 longitudinal studies necessary before this method can be
 recommended as the first choice of treatment. Yet, in
 specific situations, it can be a viable alternative method with
 an acceptable success rate.

37. Conclusions
 In dental literature reported that intrusion can be
prevented with using rigid connectors,
 bone resorption can be reduced with using
nonrigid connector in tooth-implant connection.
 As a result, undesirable cases can be avoided with
some
 precautions;

38. Pier abutment
 TOOTH IMPLANT TOOTH
 IMPLANT TOOTH IMPLANT