Dental Implants: Types and Success

Dental Implants

• An alloplastic material/device is surgically placed into oral tissue, beneath mucosal or periosteal layers, and/or within bone.
• Used to provide retention and support for fixed or removable prostheses.

Implant Classification: Morphology, Material, Position

• Subperiosteal implants involve two surgeries: creating a flap, exposing bone, using PVS to impress the alveolar bone, and fabricating/positioning the implant.
• Transosseous implants use an extra-oral surgical approach with one appointment; can scar.
• Endosseous implants include blade, cylinder, and screw types.

Success Rates (5-10 Years)

• Subperiosteal implants: 60-90% (5-year), 36-64% (10-year).
• Blade implants: 42-66% (5-year), 40-50% (10-year).
• Bone Staple (Transosseous): 93% (5-year), 86% (10-year).
• Bone Staple had better success rates in 5-10 years.

Osseointegration

• It's is a direct structural and functional connection between living bone and implant surface.
• It's is a biological concept defined as dynamic and technique-sensitive.
• Osseointegration subject to host variables like biocompatibility, macro/microstructure, surgical techniques, loading time & bone state.

Titanium for Implants

• 100% Ti (CPT) or 90% Ti with 6% Aluminum and 4% Vanadium are options for Ti implant composition.
• Higher grades have increased tensile strength & oxide layer.
• Straumann grade 4 uses cold working for higher strength.
• It has low solubility, is non-toxic, has low charged particles, a dielectric constant like water, metal surface passiveness, no soft/hard tissue reactions.

Titanium Dioxide Layer

• Titanium oxide layer is 50-100 angstroms thick, forms quickly, and is physiologically stable.
• Properties include hydration, calcium/phosphate absorption, and interaction with small biomolecules.

Roxolidx

• Ti-Zirconia implant which is is an alloy of titanium & zirconium (~15% Zr).
• Every 6th-8th atom is replaced by Zr; it is monophase-acting like a pure metal.
• Alloying increases strength compared to pure titanium.
• Roxolid has higher tensile strength even vs annealed/cold-worked pure titanium.
• Roxolid used to increase strength in narrow diameter implants.

Implant Surface Properties

• Smooth/polished or rough surfaces are options (modern implants are rough).
• Implant surface influences osteoblast behavior with chemical, energy, morphology, roughness properties affecting cell attachment, migration, proliferation.
• Combining surface morphology and roughness is key to bone apposition and osseointegration success.
• Lower contact angles relate to higher surface energy/faster healing.

Implant Configurations, Screws, and Surfaces

• Cylinders: Hydroxyapatite (HA) enhances bone contact; concerns are porosity, separation, dissolution.
• Titanium Plasma Spray (TPS) and Acid Etched options exist.
• Screws: Machined surface (plain), Hydroxyapatite, Titanium Plasma Spray, Acid Etched, Sandblasted & Acid Etched (SLA), and Anodized (Ti-Unite).
• SLActive surfaces are hydrophilic.

Implant stability

• SLA surface made in a nitrogen atmosphere
• Hydrophilic surfaces allow blood to cover more of the available surface areas.
• Stability tracked to find breakpoint (decreasing to increasing stability); stability dip ~3-4 weeks.
• Mandible breakpoints: SLA at week 4, SLActive at week 2.
• Maxilla breakpoints: No significance due to insufficient patient numbers.
• SLActive shows earlier stability increase and faster osseointegration.

Custom Implants

• Root form implants created from cone beam scans; zirconia splints bond to adjacent teeth for primary stability.
• Clinical Objective is a root-form implant is a good alternate a regular implant: immediate; straight insertion, no drilling, reduced risk of nerve damage, esthetics, function.

Implant Success

• Dental implants successful > 95%.
• Mandible is generally more successful then placement in the Maxilla
• Location: Anterior mand > Anterior maxilla > Posterior mand > Posterior maxilla > Grafted areas

Success Criteria for implants

• Individual unattached implant is immobile.
• No radiolucency.
• Vertical bone loss is < 0.2mm annually after year 1; aim for < 0.5mm in year 1, < 0.1mm annually after.
• Absence of irreversible symptoms like pain, infections, paresthesia.
• Success rate: 85% (5-year), 80% (10-year) is minimum.
• Implant allows proper crown appearance.

Surgical Considerations

• Systemic factors: cardiovascular, pulmonary, endocrine, hepatic, medications, radiation.
• Anatomic factors: Nerves, Vessels, Sinuses, Teeth.
• Dental factors: extraoral/intraoral, Occlusion, Periodontal evaluation, Radiographic analysis.
• Site Evaluation: Intra-Arch Distance, Inter-Arch Distance, Implant Diameter and Soft Tissue
• Intra-Arch Distance: Buccal-lingual width & mesial-distal width is a minimum of 7mm; 1.5-2mm space is needed between implant/adjacent tooth.
• Inter-Arch Distance: 7mm minimum from implant platform to opposing occlusal surface.
• Implant Diameter: 1mm bone around implant, 2mm preferred; 1.5mm implant platform to adjacent tooth root is needed & 3mm between implants.
• Keratinized Soft Tissue: 4mm, 2mm buccal & lingual. Mucosa leads to bone recession.

Bone Quality

• D1 is compact and cortical bone.
• D2 is thick cortical bone surrounds highly trabecular bone
• D3 is thin cortical bone surrounds highly trabecular bone
• D4 is thin cortical bone and spongy core

Implant Site Changes

• After Extraction: Ridge loses 3.87mm width & 1.67mm height.
• Need 2mm buccal plate to maintain socket wall
• 87% of anterior sites less than 1mm thickness, 3% greater than 2mm.
• 59% of posterior sites less than 1mm thickness, 9% greater than 2mm.

Ridge preservation

• Ridge Preservation reduces alveolar resorption and preserves dimensions.
• Ridge Preservation may enhance pontic site development
• You will Lose 1.2mm width and gain 1.3mm height by doing Ridge Preservation _ You Still Lose width following extraction and RP
• Augment the buccal plate with bone (consider bovine bone) in esthetic cases to avoid losing the buccal plate on the implant.

Ridge Preservation Keys

• Atraumatic extraction
• Complete soft tissue removal
• Bone graft
• Stability of membrane
• Closure

Ridge Augmentation

• Goals are to gain both width for implant placement
• Horizontal augmentation is more predictable than vertical
• Block bone graft: uses bone harvested from the ramus, chin, or hip, held in place with screws.

Ridge augmentation alternatives

• Particulate Graft: use particulate bone normally allograft and stabilized with a membrane
• Ridge split: Split of the crest ridge
• Sinus augmentation: if you lose blood supply, the bone sloughs off, and more damage occurs.

Bone Allografts and Xenografts

• Autogenous Bone Grafting: Gold standard.
• Autogenous done via osteoinduction, osteoconduction and requires second surgery.
• Xenografting: Very slow resorbtion and is radiolucent.
• Allografts: Is required to have a second site

Membranes

• Resorbables include collagen (porcine/bovine) are resorbable. Length of resorption varies based on material.
• Tissue will Granule over surface.
• Non Resorbable: PTfe, titanium-reinforced PTFE, Dermis (human). Generates additional keratinized tissue.
• Some membranes have some Titanium added for rigidity

Radiographic Evaluation

• For success use radiographic, for accurate information to support placement of implants
• Pre-operative eval to identify location, pathosis, determine quality of bone, orientation of implant vs alveolar process
• Post-operative Eval to check location for Anatomic structure to check bone and levels

Radiology Roles

• Assist the radiologist
• Benefit by being their friend

Radiology Landmarks

• Maxillary Landmarks include incisive canal, sinus and foramen
• Least density and highest failure in Maxillary Posterior
• Mandibular Landmarks include mental foramen as well as the inferior alveolar canal
• The mental foramen lies in-between the pre-molars

Bone Quality in Radiology

• Not good to use the type 1 quality because less vascularization present Good Intial Eval •

Radiology Techniques

Post implantation monitoring

• Better to use in 3D
• Mesial-distal dimension must be parallel

Radiology Views

Radiographic evaluation provides most accurate, indispensable information for successful placement of implants. • Pre-operative evaluation • Identify Inta and post use

• Panoramic good for bone pathoses, but is very difficult to interpret

Film

• Use central layer for better view of Image
• Varies slowly if any issues, is also identical

Positioning Tools for Film

Good to use positioning like minimal distortion as a part of focal though

CBCT tool for analysis

• Helps customized whole head scan

radiation levels

To minimize patient exposure and maximize image quality: • Limit your FOV to the ROI (region of interest

Tools used in radiology

• A stent is an appliance used as • a marker for radiographic evaluation • a guide for surgical procedure • The surgeon would prefer to position the implan

The restorative dentist requires implant placement that

To ensure the following. • optimum function • maximum esthetic value •relative mechanical ease

Implant Placement Risk Eval

• Patient history, periodontal and dental status must be examined
• Patients expectations must be set

Space considerations for implants

• interdental has to be considered in space
• Min 1.3m from adjacent roots
• For best esthetics place implant shoulder 3.4mm apical to the gingival margin

Implant Analysis must Eval

• the height, weight, and volume • Evaluate vital structures (IA nerve)

Anatomical Considerations

• The surgeon must always check floor of At least 1mm inferior to the floor of the maxillary sinus

Implant Sequencing

• Start with initial drill
• Use verification of Gauge to guide

Implant packing and placing

• A claim is made Osteointegration occurs between 2-6 weeks

Procedures and Instruments must be checked to ensure surgery is carried out well

• Always have 20 RPM and torque at 35Ncm
• Ensure to guide supported

Implement placement scenarios

• single and 2 stage

Stages of placement

1. Two Stage procedure = used for Bone Graft/Primary • soft bone/no primary stability/grafting cases • Also used when pt is a smoker, or has bad plaque contro
2. Single stage procedure= Done in one motion and complete

• Case selection: Evaluating risk factors
• Fabrication of a good surgical guide • Careful surgical technique: Do not overheat bone (less than 47o Celsius) • Patient follow-up and post-surgical car

Guidelines for diagnosis to ensure Treatment

• implant spacing/location must be followed

Implant Biomechanics

• to ensure abutment is very stable for connections or force
• Implant connections must be stable.
• Implant-Abutment Junctions

Implant Interface must have

• Three Basic categories of abutment connection
• functional aspect. insertion, anti-rotation and sea

Morse Taper

Non-rotation through mechanical lock: • 8° or less will yield a mechanically locking friction fit •ITI abutments have an 8 degree taper. This allows for the mechanically locking fit. Morse taper = cone within a cone • Morse taper absorbs 91% of the functional load

Implant

Stability = Prosthetic

Implement bone placement

• bone must be at a certain stimulation point
• excellent and fatigue strengths
• Force distribution must be similar

Adverse reaction to Implant placement

• This is caused by heavy occlusal forces