Tooth Loss and Prosthetic Appliances REF: Prosthodontics. Principles and Management Strategies.1996, Owall, Kayser and Carlsson, Chap. 3, pp. 35-47. Samar Al Saleh

Tooth – type and function Aesthetic units Occlusal units Samar Al Saleh

Functional classification of the 28 teeth or 14 pairs of antagonistic units Location Name Number Anterior area Aesthetic units 6 Premolar area Occlusal units 4 Molar area 4 (81) Total Functional units 14 (181) 1 in premolar equivalents. Samar Al Saleh

Healthy or Physiological Occlusion Absence of pathologic manifestations Satisfactory function Variability in form and function Adaptive capacity Samar Al Saleh

Functional assessment of the different tooth types Anteriors Premolars Molars Biting + - Chewing Speech Aesthetics ± Stability of: TMJ Dental arch + = Prime involvement; - = No, or secondary involvement. (Stuart and Stallard,1960) Samar Al Saleh

Can anterior teeth and premolars compensate for the function of the molars? (shortened dental arch) Samar Al Saleh

Schematic representation of the aetiology of an impaired dentition Samar Al Saleh

Natural history of the dentition in high-risk groups Healthy dentition Minor changes (intact occlusion) Major changes (impaired occlusion) Edentulousness (lost occlusion) Loss of alveolar bone Samar Al Saleh

Biological and functional aspect of tooth loss Samar Al Saleh

Changes following tooth loss Pathological condition Adaptation or Pathological condition Samar Al Saleh

Spontaneous closure of open space in a 32-year-old man after loss of tooth 11 at the age of 12 years due to trauma Samar Al Saleh

Effects of tooth loss on the remaining dentition Samar Al Saleh

Radiographs of a 52-year-old woman (1992) showing structural and functional stability of an extreme shortened dental arch (8 occluding units) after 20 years (a) and 28 years of function (b). Samar Al Saleh

Local factors influence the consequences of tooth loss Location of the lost tooth Number of the lost teeth Intercuspation Periodontal condition Position of the tongue Samar Al Saleh

Systemic factors influence the consequences of tooth loss Age Adaptive capacity General resistance Neuromuscular tolerance Psychological condition Samar Al Saleh

Sequelae of tooth loss Migration Unilateral chewing Alveolar bone loss Occlusal interference Loss of proximal contact Overloading of anteriors Loss of VD TMD Samar Al Saleh

General Pattern of Tooth Loss Molars then premolars. Lastly the lower anteriors. Samar Al Saleh

Possible migration after loss of tooth 36 Samar Al Saleh

(a) (b) (a) A new occlusal balance was established after loss of teeth 46 and 47 at the age of 22 years in a 28-year-old woman (1971), followed during 11 years. (b) alveolar bone height in 1971 and 1984. Samar Al Saleh

Loss in the anterior region Disturbed aesthetics Disturbed speech Affected psychosocial function Samar Al Saleh

Patterns in partial edentulism Eichners classification (no. of remaining occlusal supporting zones) Simple classification of impaired dentitions Uncomplicated Complicated Partial edentulism Tooth boundspace Shortened dental arch Samar Al Saleh

The Eichner Index, based on supporting zones of antagonist contacts in premolar and molar regions (Helldén et al., 1989) A1 A2 A3 B1 B2 B3 B4 C1 C2 C3 Samar Al Saleh

Uncomplicated tooth-bound space in the left mandible Complicated tooth-bound space, showing migration of remaining teeth Samar Al Saleh

Uncomplicated shortened dental arch Complicated shortened dental arch: migration of remaining teeth, loss of vertical dimension and dislocation of condyle Samar Al Saleh

Compensation of tooth loss Chewing where most occlusal contact More chewing strokes Swallowing of larger particles Samar Al Saleh

Migration in tooth bound spaces Distally located teeth drift and tip mesially Mesially located teeth drift and tip distally Extrusion with no opposing contact Samar Al Saleh

Migration Premature contact and interferences Adaptation Pathological condition (TMD) (close in new position) Samar Al Saleh

Shortened dental arches Premolar dental arch Extreme shortened dental arch Samar Al Saleh

Complicated shortened dental arch: migration of remaining teeth, loss of vertical dimension and dislocation of condyle Samar Al Saleh

Masticatory function measuring Objectively Chewing test (masticatory performance) MP (no. of occlusal units ability) Subjectively Questionnaire or interview (masticatory) 10 occluding pairs will be sufficient Samar Al Saleh

Schematic representation of the relationship between masticatory function and dental arch length (expressed in occlusal units) 1 = Masticatory ability (perceived ease of chewing) 2 = Masticatory performance A = Area of sufficient masticatory function B = Turning range C = Area of insufficient masticatory function Samar Al Saleh

Stability of premolar dental arch Occlusal contact in IP Overbite Interdental spacing Attrition and alveolar bone support Samar Al Saleh

Effect of periodontal problems on shortened dental arches Samar Al Saleh

Oral comfort Absence of pain Satisfactory masticatory ability Acceptable aesthetics Samar Al Saleh

Relationship between oral function and shortened dental arches 1 = Contact between anterior teeth in IP 2 = Alveolar bone height 3 = Interdental contact between anterior teeth; absence of mandibular dysfunction 4 = Chewing capacity 5 = Aesthetics A = Area of sufficient and function (adaptation) B = Turning range C = Area of insufficient oral function Samar Al Saleh

Dental arch support and TMJ ? Posterior tooth loss TMJ osteoarthrosis Samar Al Saleh

Implications for prosthetic treatment 28 tooth syndrome Over treatment Samar Al Saleh

To maintain a healthy natural functioning dentition for life Dental Care Aim To maintain a healthy natural functioning dentition for life Samar Al Saleh

“The exact number of teeth each individual need, can not be ascertained by the dental profession.” “If patient manage well with any number of teeth, then there is no reason to recommend prosthetic appliances.” Samar Al Saleh

Oral Function Level Optimal Sub-optimal Minimal Samar Al Saleh

Required oral functional level in relation to age, expressed as the minimum number of occluding pairs of teeth (arch length)1 Age (years) Functional level Occluding pairs 20 – 50 I: Optimal 12 40 – 80 II: Suboptimal 10 (SDA) 70 – 100 III: Minimal 8 (ESDA) 1 SDA = Shortened dental arch; EDSA = Extreme shortened dental arch Samar Al Saleh

The Shortened Dental Arch Concept Samar Al Saleh

The occlusal preservation target in high-risk groups I = Complete dental arch (optimal function) II = Shortened dental arch (suboptimal function) III = Extreme shortened dental arch (minimal function) A = High-risk factors (caries, pockets) B = Limiting factors (restricted finances) C = Patient factors (poor general health) The occlusal preservation target in high-risk groups Samar Al Saleh

The prosthetic treatment target in high risk groups The prosthetic treatment target in high risk groups. The number of teeth to be restored is dictated by the needed functional level. Samar Al Saleh

Teeth should be replaced for Aesthetics Functional comfort Occlusal stability Samar Al Saleh

Lecture No.2 Pre-edentulism Ref: Prosthodontics. Principles and Management Strategies. 1996, Owall, Kayser and Carlsson, Chap. 4, pp. 49-47. Samar Al Saleh

Natural history of the dentition in high-risk groups Healthy dentition Minor changes (intact occlusion) Major changes (impaired occlusion) Edentulousness (lost occlusion) Loss of alveolar bone Samar Al Saleh

The traditional restorative approach in prosthetic dentistry Samar Al Saleh

Pre-edentulous situation Just a few (non-strategic) teeth are left with poor prognosis. The distribution of the remaining teeth in the dental arches is often unfavorable  oral function cannot be performed adequately. Samar Al Saleh

Preventive prosthetic treatment for the pre-edentulous patient = Postponing of tooth extraction to prevent bone loss Samar Al Saleh

Principles of preventive prosthetic treatment for the pre-edentulous patient Treatment planning and timing of tooth extraction Shortening the dental arch with preservation of occluding pairs of teeth Use of an overdenture Samar Al Saleh

Treatment planning and timing of tooth extraction Condition of residual tooth Age Postponement of extraction delays the reduction of the alveolar ridge Extraction of teeth with severe periodontitis (targeted extraction)  less bone resorption Samar Al Saleh

Shortening the dental arch with preservation of occluding pairs of teeth Free-end RPD X shortened dental arch If no remaining occluding pairs  the remaining teeth will cause damage to opposing edentulous jaw Preventive implantology Samar Al Saleh

Due to the removal of the antagonistic tooth in the mandible, the solitary maxillary tooth has caused bone loss in the mandible Samar Al Saleh

(a) An example of a patient with a dental situation with no occluding pairs of teeth (natural versus artificial teeth) and severe alveolar bone resorption of the edentulous maxilla. (b) The teeth in the mandible are functionally “locked”. Every movement of the jaw causes the lower teeth to damage the edentulous maxilla via the upper denture. Samar Al Saleh

A dentate maxilla opposing an edentulous mandible should always be avoided. A situation of natural teeth versus artificial teeth has led to severe alveolar bone loss of the mandible Samar Al Saleh

Use of an (immediate) overdenture Preservation of the alveolar ridge Preserving lower canines Samar Al Saleh

(a) Orthopantomogram of a 45-year-old female patient (1987) with an edentulous maxilla and periodontal disease in the mandible. In spite of the poor periodontal condition, it was decided to make a complete immediate overdenture in the lower jaw, while retaining four abutment teeth. (b) The situation 6 years after treatment (1993). Good oral hygiene and plaque control using chlorhexidine (Hibigel®). Samar Al Saleh

Schematic summary of the treatment planning by a pre-edentulous patient with a residual mutilated dentition motivation, instruction treatment of periodontium and caries “targeted” extractions removable partial (immediate) denture recall Samar Al Saleh

(a) In a 61-year-old woman with poor oral hygiene, a complete immediate overdenture, while retaining both lower canines, was inserted in 1986. (b) In the clinical situation more than 7 years later (1993), oral hygiene is good, resulting in a healthy periodontium and hardly any alveolar bone loss. Samar Al Saleh

Assessment of the pre-edentulous dentition for overdentulous treatment Caries Periodontal considerations Prosthetic consideration Samar Al Saleh

Extensive and active caries Samar Al Saleh

Periodontal consideration Mobility Type of bone loss Extraction, subgingival curettage Samar Al Saleh

Samar Al Saleh

Endodontic Consideration Single rooted canal and apical radiolucency Successful endo treated tooth Samar Al Saleh

Prosthetic Considerations Samar Al Saleh

If the vertical jaw relationship shows sufficient denture space, abutment teeth which are (more or less) opposing should be retained Samar Al Saleh

Prosthetic considerations in the selection of abutment teeth If possible always If opposing teeth are present in the mandible in order to avoid “natural vs artificial teeth” Samar Al Saleh

Location of the abutment teeth Samar Al Saleh

The division of the jaw into four zones to facilitate the selection of abutment teeth Samar Al Saleh

Examples of the distribution of abutment teeth within the dental arch Samar Al Saleh

Canines as an overdenture abutments Longest teeth Strategic position Oval-shaped root Easy endo treatment Samar Al Saleh

(b) In the clinical situation more than 7 years later (1993), oral hygiene is good, resulting in a healthy periodontium and hardly any alveolar bone loss. Samar Al Saleh

Distribution of abutment teeth over the upper and lower jaw Situations in which teeth oppose an edentulous part of the jaw should be avoided. Samar Al Saleh

Many pre-edentulous situations between the lower and upper jaw are undesirable from a prosthetic point of view (green in illustration). The figure indicates which dental situations offer a good starting point for making an overdenture. Samar Al Saleh

A “targeted extraction strategy”, possibly combined with the making of an overdenture, enables the balance of forces between the dental arches to be restored. (NB The use of dental implants makes other combinations possible) Samar Al Saleh

Dental implants as abutment teeth for overdentures (a) The use of implants in the lower jaw restores the balance between the dental arches. (b) Reduction of tooth material in the lower jaw can be avoided by inserting implants in the upper jaw. Samar Al Saleh

The main goal in “preventive prosthodontics” is the preservation of oral function for life. Dental implants can effectively “reverse” complete edentulousness and restore oral function Samar Al Saleh

Submerged roots and submucosal implants Root of fractured teeth Filling the socket with biocompatible material Samar Al Saleh

Orthopantomogram of a patient with submucosal implants (calcium hydroxyapatite), inserted immediately after extraction. Samar Al Saleh

Depending on the individual rate of resorption, the upper surface of the submucosal implants will sooner or later protrude above the level of the jawbone with dehiscence of the mucosa. Samar Al Saleh