The document discusses periodontal and peri-implant innervation and proprioception. It covers the periodontal and peri-implant innervation, tactile function of teeth and implants, and factors that influence tactile function. The concept of implant osseoperception is introduced, where mechanoreceptors in peri-implant bone and periosteum are thought to provide sensory feedback in the absence of periodontal ligament receptors. Some clinical implications of reduced tactile sensitivity with implants are mentioned.

1. PERIODONTAL, PERI-IMPLANT INNERVATION AND
PROPIOCEPTION.
Dr Maryam tahir
PG trainee
periodontology

2. TABLE OF CONTENTS
1. Introduction
2. Periodontal innervation
3. Peri implant innervation
4. Tactile function of implants
5. Tactile function tests
6. Active vs passive tactile sensibility
7. Concept of implant osseoperception
8. Clinical implications
9. Conclusion
10. References

3. INTRODUCTION:
 Perception is the ability to detect external stimuli through vision, audition, balance, somatic function,
taste or smell.
 One of the main functions of the PDL in the masticatory cycle is to provide sensory feedback during
chewing.
 Humans are capable of detecting the presence of very small particles between the occlusal surfaces of
teeth. The teeth also can serve as an excellent judge of material properties.
Perception:

4.  Periodontal mechanoreceptors and especially those located in the periodontal ligament, are
extremely sensitive to external mechanical stimuli (Jacobs & van Steenberghe 1994).
 Any condition that may influence periodontal mechanoreceptors could alter the sensory
feedback pathway and thus affect tactile function and fine-tuning of jaw motor control (e.g.
periodontal breakdown, bruxism, re-implantation, anesthesia)

5.  There are proprioceptive sensors in the PDL that provide sensory information about how fast
and how hard to bite (Hannam 1982).
 Lund and Lamarre (1973) anesthetized patient’s teeth and found a 40% reduction in bite force
applied, indicating that PDL proprioceptors are important in the control of bite force

6. PERIODONTAL INNERVATION
 Periodontal receptors are located within the gingiva, jaw bone, periosteum, and periodontal
ligament.
 Most receptors seem to have mechanoreceptive characteristics, contributing to a
sophisticated exteroceptive tactile function.
 Periodontium has a rich sensory nerve supply, especially in those locations that are more
prone
to displacement (periapical, buccal, and lingual).

7.  The pdl has functionally two types of nerve fibers sensory and autonomic.
 The sensory fibers are associated with nociception and of mechanoception , with touch ,
pressure , pain and proprioceptive sensations . The autonomic fibers are associated with pdl
vessels.
 All pdl innervations are mediated by the dental branches of alveolar nerves which enter
through apical perforation of the tooth socket and perforating branches of interalveolar
nerves traversing the bone .
NERVES

8.  Nerves which usually are associated with blood vessels pass through foramina in the alveolar
bone including the apical foramen to enter the pdl . In the region of apex they run toward the
cervix whereas along the length of root they branch and run both coronally and apically .
 Nerve fibers are either of large diameter and myelinated or small diameter in which case they
may or not be myelinated .

9.  The pdl is abundantly supplied with sensory nerve fibers capable of transmitting tactile
pressure and pain sensations by the trigeminal pathways . Nerve bundles pass into pdl from
the periapical area and through channels from the alveolar bone that follow the course of the
blood vessels .
 The bundles divide into single myelinated fibers which ultimately loose their myelin sheath
and end in one of four types of neural termination
 1.Free endings which have a tree like configuration and carry pain sensation
 2. Ruffini – like mechanoreceptor located primarily in the apical area
 3. Coiled Meissner’s corpuscle also mechanoreceptor found mainly in the midroot region
 4. Spindle like pressure and vibration endings which are surrounded by a fibrous capsule and
located primarily in the apex .

10. SENSORY FUNCTIONS
NEURAL TERMINATIONS
FREE
ENDINGS -
pain
sensation
RUFFINI
MECHANO
RECEPTORS
-primarily
in apical
areas
COILED
MEISSNER’
S
CORPUSCL
E-primarily
in midroot
region
SPINDLE
LIKE
ENDINGS -
pressure
and
vibration
mainly in
apex

12. MECHANORECEPTIVE FUNCTION OF PDL
The mechanoreceptive function of the periodontal ligament signals the differential information about
the mechanical events that occur during biting and chewing.
Brain analyze and characterize these specific mechanical events, enabling further processing for fine‐tuning and
resulting in an optimized masticatory sequence.
Some sensory–motor interactions are impaired or even lost when the periodontal ligament is altered or
damaged.
When teeth are extracted and thus ligament receptors eliminated, tactile functioning may be hampered.

13. PERI-IMPLANT INNERVATION
 Tooth extraction damages a large number of sensory nerve fibers.
 After extraction of teeth, the myelinated fiber content of the inferior alveolar nerve is reduced
by 20% (Heasman 1984).
 This finding indicates that fibers originally innervating the tooth and periodontal ligament are
still present in the inferior alveolar nerve.
 Linden and Scott(1989)- succeeded in stimulating nerves of periodontal origin in healed
extractions which implies that some nerve endings remain functional.

14. MECHANISM OF TACTILE FUNCTION IN IMPLANTS
Implant has intimate bone-implant contact.
The elasticity of bone is different than that of viscoelasticity of pdl.
The forces applied to ossteointegrated implant are directly transferred to the bone instead of pdl.
These forces cause bone deformation which leads to receptors activation in peri implant bone and
neighboring periosteum.
This sensation evoked by mechanical loading of implant is known as osseoperception.

16. TACTILE FUNCTION OF ORAL IMPLANTS
 Neural receptors of the periodontium play an essential role in oral tactile function.
 Most receptors, which are found in the PDL, are evidently absent around the perimucosa of dental
implants.
 In those cases, remaining receptors of the gingiva, alveolar mucosa, and periosteum may take over the
role of normal exteroceptive function.

17. TESTING TACTILE FUNCTION
 Exteroceptive function can be examined by
 1) neurophysiologic methods
 2) psychophysical methods.

18. NEUROPHYSIOLOGIC ASSESSMENT
 Neurophysiologic investigations of the sensory function of the human trigeminal system are
risky and therefore rarely reported.
 Alternatively, non‐invasive approaches may be considered to evaluate oral tactile function.
Two types of approaches can be used
trigeminal
somatosensory
evoked
potentials (TSEPs)
magnetic
resonance imaging
(fMRI)

19. TRIGEMINAL SOMATOSENSORY EVOKED
POTENTIALS (TSEPS)

20. MAGNETIC RESONANCE IMAGING (FMRI)

21. PSYCHOPHYSICAL STUDIES
 In the literature, psychophysical threshold determination studies confirmed that patients might perceive
mechanical stimuli exerted on osseointegrated dental implants in the bone.
 Psychophysics includes a series of well defined methodologies to help determine the threshold level of
sensory receptors in man
 The tactile sensibility of teeth and/or implants may either be
active tactile sensibility passive tactile sensibility.

22. ACTIVE VS PASSIVE TACTILE SENSIBILITY
ACTIVE TENSILE SENSIBILITY PASSIVE TENSILE SENSIBILITY
It is tested by having the test persons bite on thin test
bodies.
It is tested by passively applying pressure on the occlusal
surface of the implant.
It is the interocclusal detection of small objects
such as strips, where various groups of receptors
are activated.
The passive differential threshold level is the ability
to differentiate between intensities of forces applied
to a tooth.
Active tactile sensibility is expressed by the thickness
of the thinnest foreign body perceived (mm)
The results for passive tactile sensibility are expressed by
the minimum pressure that was perceived through the
implant (N)
In active perception, various groups of receptors
are activated(mucosa, bone ,muscles etc)
Passive perception electively addresses the PDL
receptors missing after the extraction of the tooth

23. .
ACTIVE TENSILE SENSIBILITY PASSIVE TENSILE SENSIBILITY
In comparison with the tactile function of natural
dentitions, the active threshold is seven to eight
times higher for dentures.
Passive threshold is 75 times higher for dentures s
compared to natural dentition.
Active threshold is only three to five times higher for
implants as compared to natural dentition.
Passive threshold is 5 times higher for implants as
compared to natural dentition.

25. FACTORS INFLUENCING THE TACTILE FUNCTION OF TEETH

26. ORAL STEREOGNOSIS
 The stereognostic ability is defined as the ability to recognize and discriminate different forms presented as a stimulus.
 Stereognosis is a complex process. It is a function of both peripheral receptors (touch and kinaesthetic)
and central integrating processes.
 To assess the stereognostic ability, test pieces (different shapes)are inserted in the oral cavity and in
most experimental set-ups free manipulation of the test pieces is allowed.
 This activates a large number of receptor groups (periodontal, mucosal, muscular, articular, etc.]
ASSESMENT OF STEROEGNOSTIC ABILITY

27.  A good result in a stereognosis test should indicate that the subject receives full and accurate
information about what is going on in the mouth.
 Stereognostic ability testing is not designed to detect specific receptor groups, it rather reflects an
overall sensory ability.

28.  After a bilateral mandibular block, the stereognostic ability decreases with about 20%.
 When comparing teeth with full dentures, a far better stereognostic ability is noted for natural teeth when
freely manipulating the test pieces.
 When removing the denture(s) in complete denture wearers, a considerable reduction in stereognostic
ability is noted

29. CONCEPT OF IMPLANT OSSEOPERCEPTION:
• Osseoperception is defined as mechanoreception in the absence of a functional periodontal
mechanoreceptive input.
• It is derived from TMJ, muscle, cutaneous, mucosal, periosteal mechanoreceptors which provide
mechanosensory information for oral kinaesthetic sensibility in relation to the jaw function and the
contacts of artificial teeth.

30.  It is not clear how the neurophysiological mechanisms that modulate jaw movement are associated with
the sensory structures around the osseointegrated dental implants.
 Based on neural inputs, associated with jaw movements, various theories have been put forth by
different authors.

31. THEORIES OF OSSEOPERCEPTION:
 Linden RWA, Scott BJJ in 1989
periodontal receptors remain within the bone after extraction.
 Bonte B et al., in 1993
Suggest reinnervation in association with controlled forces directed to implants.
 Klineberg I, Murray G in1999
Suggests that tempromandibular joint receptors substitute for periodontal ligament receptors of natural teeth.
 Van Steenberghe D in 2000
Suggests that periosteum may be the source of proprioceptive responses.
 Weiner S et al., in 2004
Suggests that bone adjacent to implants contain nerve fibers.

32. POTENTIAL MECHANORECEPTORS CONTRIBUTING TO
OSSEOPERCEPTION
 (a) Joint Mechanoreceptors:
 Low-threshold mechanoreceptors are present in the TMJs.
 These receptors in humans play a protective role.
 They also has a limited role in signaling movements and positions of joints.

33.  (b) Muscle Mechanoreceptors:
 The principal mechanoreceptors associated with muscle are GTOs( golgi tendon organs)
 Golgi tendon organs are found at the musculo-tendinous junction in series with a small number of extra fusal
muscle fibers, and the pull of the muscle fibers with muscle contraction activates GTOs.
 Golgi tendon organs associated with jaw muscles play an important role in regulating muscle contraction and
signaling intramuscular tension.
 These receptors, together with corollary discharge, are likely to make important contributions to the sense of
intramuscular tension generated during voluntary contractions such as biting.

34.  (c) Mucosal Mechanoreceptors:
 With implant-supported prostheses opposing complete dentures, a contribution to oral kinaesthetic perception
could come from the activation of mucosal receptors beneath the prosthesis
 In the oral mucosa, different types of mechanoreceptors can be identified including Meissner’s corpuscules,
glomerular endings, Merkel cells, Ruffini-like endings, and free nerve endings

35.  (d) Periosteal Mechanoreceptors
 The periosteum contains free nerve endings, complex unencapsulated and encapsulated endings.
 The free nerve endings are activated by pressure or stretching of the periosteum through the action of masticatory
muscles and the skin.
 When applying forces to osseointegrated implants in the jaw bone, it might be assumed that the pressure build-up
in the bone is sometimes large enough to allow deformation of the bone and its surrounding periosteum.

36. FROM PERIODONTAL TACTILE FUNCTION TO PERI‐IMPLANT
OSSEOPERCEPTION
Henry et al.
(2005)
Extracted lower incisors in mole rats and with fMRI analysis showed a reorganization
of the orofacial representation in the primary sensory cortex 5–8 months later.
Lundborg et al.
(2006)
MRI study demonstrated that upon tactile stimulation of an osseointegrated prosthetic
thumb, the primary somatosensory cortex is bilaterally activated in an area
corresponding to that of the hand.
Habre‐Hallage et
al. (2010)
This group recently found that upon stimulation of implants and teeth, the
somatosensory cortex was activated
Neurophysiologic evidence for the cortical plasticity with representation of the implant in the sensory cortex
can be found in some experiments evoking TSEPs upon implant stimulation.

37. CLINICAL IMPLICATIONS
 The concept of osseoperception can help us to restore the habitual
masticatory physiologic function with ossointegrated implant supported
prostheses, despite the absence of periodontal mechano receptors which are
an important component of neuromuscular coordination.

38. Considering the increased tactile threshold level for oral implant stimulation, a few clinical
implications should be considered
 During rehabilitation by means of implant-supported prostheses, a dentist should not rely on
the patient’s perception of occlusion.
 To avoid any overloading related to suboptimal feedback mechanisms, patients should be
encouraged to limit chewing forces by eating only soft foods during the healing period.
 Furthermore, parafunctional habits such as grinding or clenching might have a negative
impact during the implant healing phase.

39. CONCLUSION
 Sensory feedback plays an essential role in the fine tuning of jaw and limb motor control.
 Periodontal mechanoreceptors play the key role in tactile function of the teeth, yielding
detection thresholds of a thickness of about 20 μm between antagonistic teeth and 1–2 g
upon tooth loading.
 It is clear that any condition that may influence periodontal mechanoreceptors may also alter
the sensory feedback pathway, and thus influence tactile function and modulation of jaw
motor control.
 After placement of oral implants, detection thresholds are increased to a thickness of at least
50‐100 μm and 50–100 g upon tooth loading

40.  “Osseoperception” phenomenon remains a matter of debate, but it is assumed that
mechanoreceptors in the peri‐implant bone and neighboring periosteum may be activated
upon implant loading.
 This implant‐mediated sensory–motor control may have important clinical implications,
because a more natural functioning can be attempted with implant‐supported prostheses.

41. REFRENCES
 Lindhe ( 6th edition)
 Jacobs R, van Steenberghe D. From osseoperception to implant-mediated sensory-motor interactions and related
clinical implications. J Oral Rehabil 2006;33(4):282-292
 Jacobs R, van Steenberghe D. Role of periodontal ligament receptors in the tactile function of teeth: A review. J
Periodont Res 1994;29:153-167.
 Bhatnagar VM, Karani JT, Khanna A, Badwaik P, Pai A. Osseoperception: an implant mediated sensory motor
control-a review. Journal of clinical and diagnostic research: JCDR. 2015 Sep;9(9):ZE18.
 Dhall RS, Gupta G, Ahluwalia S, Rawat A, Gaur A. Osseoperception in Dental Implants. IP International Journal of
Periodontology and Implantology. 2021 Feb 15;2(4):130-5.
 Kumar L, Singh BP, Rao J, Singh K. Osseoperception in Implants Supported Prosthesis-A. Online Journal of Medicine
and Medical Science Research. 2012 Apr;1(1):1-4.
 Mishra SK, Chowdhary R, Chrcanovic BR, Brånemark PI. Osseoperception in dental implants: a systematic review.
Journal of Prosthodontics. 2016 Apr;25(3):185-95.

42. THANKYOU!

43. ANY QUESTIONS!?