DENTAL IMPLANTS
Content
Dental Implants
direct structural Osseointegration : The between and functional connection ordered, living bone and the surface of a loadcarrying implant .
Biomaterials: Biologically compatible materials that can be used for manufacturing of implants They include: A. Metals and metal alloys: most widely used material is titanium and its alloy B. Ceramics and carbons: aluminum oxide, carbon, carbon-silicon compound, and hydroxyapatite C. Polymer Polymerss and compos composites: ites: includes includes cross-linked polymers (silicone, rubber, polyethylene) not in general use at present.
The Peri-implant mucosa: 1. Mucosal tissue dense collagenous lamina propria covered by stratified squamous kertinizing epithelium. 2. Implant epithelium junction junction (junctional epithelium) epithelium) hemidesmosomes and a basal lamina. 3. Sulculs around the implant 1.5 – 2 mm depth
sulcular epithelium with
4. Capillary loops found in the C.T similar to normal periodontium anatomically but with reduced vascularity 5. Collagen fibers
nonattached and run parallel
6. The marginal portion of the peri-implant mucosa collagen + # fibroblasts
The Implant – Bone interface: 1. Osseointegration: Osseointegration: - There is an absence of C.T. or any non bone tissue in the interface between the implant and the bone at the light microscope level. - Successful cases will have 30% and 95% of the implant surface in contact with bone. - After an initial remodeling in the first year that results in .9-1.6 mm of bone reduction, the bone level around healthy functioning implants remains stable. - Compact bone offers a much greater surface area for
mineralized tissueimplant contact bone ! maxilla maxilla has to lower success ratesthan then cancellous mandible. 2. Fibro-osseous integration - In which soft tissue (fibers and/or cells) are interposed between the implant and the bone.
II - Clinical Aspects of Dental Implant
Clinical management A.Appropriate selection of cases B.Adequate preparation of biomaterials biomaterials C.Careful handling of patient’s soft and hard tissue
A - Appropriate selection of cases 1. Pt must be in good general health 2. Good oral hygiene 3. Good periodontal health ( bacterial flora in periodontitis can jeopardize jeopardize the healing of the implant sites) 4. Resteration present 5. Level of decay activity 6. Cause for previous tooth loss 7. Pt motivation 8. Appropriate occlusal forces forces 9. Bone quantity and quality quality palpation, bone sounding and radio-graphs (panoramic, periapical, lateral, cephalometric, CT. scan) – minimal width of the jaw bone is 6 mm , minimal height is 10
10. Soft tissue quality and quantity good keratinized, attached attached mucosa for better functional and aesthetic results for implant restoration
B – Adequate preparation of biomaterials To achieve an osseointegrated implant with a high degree of predictability. The implant must be: 1. Sterile 2. Made of a biocompatible material 3. Inserted with an atraumatic surgical technique (heat)
4. Placed with initial stability 5. Not functionally loaded during the healing period of 4-6 months.
C-soft Careful of patients1. tissueshandling Aviod over heating of bone 2. Good handiling of soft during suturing
tissues
Various implant systems The systems differ in: 1. Biomaterial a) pure titanium b) plasma-spra plasma-sprayed yed titanium surfaces surfaces c) plasma-spra plasma-sprayed yed hydroxyapatite hydroxyapatite surfaces
2. Design a)screw-shaped screw-shaped ( threaded ) b)cylinder-shaped cylinder-shaped c) Tapered Tapered screw-shaped
3. Surgical procedures procedures a) Immediate ( at the the time of extraction extraction ) b) Delayed ( 2 monthes monthes after extraction extraction to allow for for soft tissue healing healing ) c) staged ----------- 1- one one stage 2- tow stage stage ( 4 – 6 monthes after after extraction extraction to allow for bone healing ) * Implants come with different lengths (7-20 mm) and widths (3.25-6 mm) to accommodate the available bone quantity.
- There are more than 50 types of implant systems world wide, many lack short – and
long data . Examples of implant systems with good clinical and experimental research are : 1- Nobel Biocare System 2- International Team for Oral Implantology (ITI) System 33i ( Implant Innovations ) System 4- Astra dental Implant System
System Nobel Biocare System developed by Branemark in swed sw eden en in th thee ea earl rlyy 196 1960s 0s - it is a machined pure titanium screw-shap apeed
im - imp Ti-plant unite-------- TPS coating - SteriOss system --------Replace (tapered titanium implant which comes in an acidetched, TPS, HA coatin )
• Intrnational Team for Oral Implant ( ITI ) System - developed in Switzeriand by Schroeder and colleagues colle agues in the the early early 1970s 1970s - it comes in different designs ( hollow ylinder,characteristic-----befor full-body screw ) - csurface it was plasma-sprayed titanium titanium coating, now it is sand-blasted, acid-etched surface - implant protrudes through the mucosa adva.------- no second surgery, disadva.----- 1- premature loading 2- danger of titanium showing in the marginal mucosal area
3i (Implant Innovations ) System - dev devel elop oped ed by by Laz Lazza zara ra an and d Bea Beaty ty in 19 1988 88 - it 1or 2-stage commercially pure titanium screw and cylinder implant with either an acid etched, TPS, HA coated surface - new implant------- rough middle and apical part ( for better bone integration ) and smooth coronal part ( for better maintenance properties )
Astra -Dental develoImplant de ped pe d in in th thSystem e 19 1980s iin n Sw Swedwn - it is a pure titanium screw shaped implant with an oxide-blasted coating - it comes with conical abutment that fits tightly into the coronal part of the implant
Surgical Aspects of Dental Implants
Staged Implant placement
One Stage:
Two Stage:
Recommendations ations for two-stage implant Recommend surgery
For both one and two-stage implant approach the implant should not be loaded for 2-3 months in the mandible and for 4-6 months in the maxilla
Adjunctive Advanced Surgical Techniques
1. Internal 2. External
Implant Reconstruction 1. Fully edentulous arches A - Fixed (Screwed cemented) B - Overdenture (clips + bar) 2. Partially Partially edentulous 1 - Single tooth 2 - Multiple teeth
Complications
1. Early Early onset (during the treatment phase) mobility after the healing period 2. Late onset (during the maintenance phase) mucosal inflammation, progressive bone loss and mechanical problem
Maintenance Phase - Proper oral hygiene and appropriate occlusal forces are critical for long-term function of an implant prosthesis. - Recalls should be every 3 months for the first year, and then every 6 months - Evaluation of oral hygiene, occlusal harmony implant and prosthesis stability, and hard peri-implant tissue overall health,soft and radiographic follow up.
III - Diagnosis and Treatment of PeriImplant Disease
- Peri-implant Peri-implant
disease:
Pathologic
changes of the peri-implant tissues - Peri-implant Peri-implant mucositis: inflammatory changes which are confined to the soft tissue surrounding an implant - Peri-implantitis: Peri-implantitis: progressive periimplant bone loss in conjunction with a soft tissue inflammatory lesion. the over all frequency of periimplantitis is in the ran ra nge of 5% to 10 10% % - the mea ean n crestal bone around an implant decreases 0.9 to 1.6 mm during the first year of implant function
Etiology A.Bacterial infection B.Biomechanical factors C.Cofactors
A - Bacterial infection - Plaque accumulation of the implant surface
subepithelial C.T becomes infiltrated by large number of inflammatory cells ulcerated and loosely adherent epithelium plaque migrates more apically clinical and radiographic signs of tissue destruction - Bacterial flora in adult periodontitis and peri-implantit peri-implantitis is have great similarities similarities - Bacterial flora in totally edentulous and partially edentulous mouth is different. Q: Why is the the size of the the soft tissue tissue inflammation inflammation and bone bone loss greater around implants implants than around teeth? A: 1. Low Low vascularity soft tissue band around the implant implant 2. Difference Difference in the collagen-to-fibro collagen-to-fibroblast blast ratio of the gingival tissue (affects the defense mechanisms) 3. Implant Implant surface characteristics (Hyroxyapatite coated implant vS. Titanium coated implants)
B - Biomechanical Factors - Excessive biomechanical forces that lead to high stress or microfractures in the coronal bone – to – implant contact which which lead to less of
-
osseointegration around the neck of the implant The role of loading has increased influence in: 1. The The implant is placed in poor-quality bone
2. Poor load distribution distribution 3. Parafunction
4. The The prosthetic superstructure does not fit the implants precisely.
C – Co factors 1. Traumatic surgical techniques 2. Inadequate Inadequate amount of host bone 3. Co Comp mpro romi mise sed d ho host st re resp spon onse se 4. Smoking
Signs of peri-implant disease 1. Pocket formation penetration is 3 to( 4normal mm ) probe
2. Radiographic bone destruction destruction (normal periimplant bone level is 1 mm apical to the position of the probe tip)
3. Suppuration 4. Calculus build up 5. Swelling 6. Color changes 7. Bleeding on probing 8. mobility
Treatment of peri-implantitis A – Occlusal Therapy Therapy 1. Analysis of the the fit of the prosthesis prosthesis
change in the
prosthesis design design 2. Analysis of the the number and position of the the implants force distribution distribution 3. Occlusal evaluation
occlusal adjucment
B – Anti-infective therapy 1. Removal of plaque plaque and polishing polishing with high-pressure high-pressure air powder abrasive ( sodium bicarbonate bicarbonate and sterile sterile water ) 2. O.H. Re-inforcment 3. Subgingival irrigation of the peri-implant peri-implant pockets with chlorhexidine 4. Systemic antibiotics antibiotics for 10 days ( doxycycline and metronidazolee ) metronidazol
C – Surgical Therapy 1. Resective therapy ! To To # pocket pocket + correct negative osseous architecture + " the the area of keratinized gingiva 2. Regenerative therapy therapy ! to to # pocket pocket with regeneration of lost bone tissue
Morphology of Osseous Defect • Group I = moderate horizontal bone loss with minimal intrabony component • Group II = moderate to severe horizontal bone loss with minimal intrabony component • Group III = minimal to moderate horizontal bone loss with an advanced circumferential intrabony • lesion Group IV = moderate horizontal bone loss with an advanced circumferential intrabony lesion + the buccal and \ or lingual plate has been lost
Indication for Nonsurgical Therapy 1. Mucosal inflammation 2. Radiographic bone level stable 3. Phase I therapy before before surgery
Indications for Resective Therapy 1. Moderate to advanced horizontal horizontal bone loss 2. Moderate vertical bone defect defect ( < 3mm ) 3. One and two wall defects 4. Implant position in nonaesthetic area
Indications for Regenerative Therapy 1. Implant Implant allows complete closure with flap 2. Moderate Moderate to advanced vertical defects 3. Two and three wall bone defects 4. Detoxification Detoxification of implant surface possible
Indications for Implant Removal
1. 2. 3. 4. 5.
Severe peri-implant peri-implant bone loss (> 50%) 50%) Unfavorable advanced bone defect (one wall) Rapid, severe bone bone destruction (within (within 1 year of loading) loading) Non surgical or surgical therapy therapy ineffective Esth thet etiic ar area ea pr prec eclludi din ng im imp pla lan nt su surrfa face ce exposure
Surgical gical Aspects of of Dental Implants Implants Sur At the end of the lecture, students should be able to: Know how to select suitable cases for implant cases therapy Know complications of implants and how to maintain implant patients Know the different techniques of endosseous implant surgeries Explain how to diagnose and treat peri-implant disease
