Recent Advances In Implant Dentistry

Recent Advances In Implant Dentistry

Recent advances in surgical techniques.

Dental Implants Introduction

• Placements of dental implants are by either one-stage surgery or two-stage surgery in an ideal situation
• In limitations, such as bony defects, soft tissue defects, bony imperfections, and inadequate bone dimensions, advanced surgical options are done.

Classification of advanced surgical procedures

Regenerative procedures

• Bone augmentation procedures
  • Sinus elevation procedures
    • Direct sinus lift
    • Indirect sinus lift

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• • Bone grafting/regeneration procedures
    • Vertical grafting
      • Distraction osteogenesis
    • Horizontal grafting
      • Onlay grafting
      • Sandwich grafting
  • Guided bone regeneration procedures
• Gingiva augmentation procedures
  • Free gingival grafts
  • Connective tissue grafts
  • Pedicle grafts
  • Guided tissue regeneration procedures

Respective procedures

• Bone respective procedures
• Soft tissue respective procedures

Sinus Elevation Procedure Definition

It is a surgical procedure that increases the amount of bone in the posterior maxilla. The bone grafting material is deposited on the inferior wall or floor of the sinus to increase the bone dimensions available for implants in the maxillary posterior region.

Surgical Techniques Indications

• Decreased bone height in the posterior maxilla
• Implant restoration with deficient bone dimensions (length) in the posterior maxilla.

Surgical Techniques Contraindications

• The presence of sinus infections, inflammation, and pathologic growth
• Systemic diseases that have poor prognosis for healing
• Psychological impairment.

Surgical Technique Procedure

Based on the surgical approach a direct or indirect technique can be done.

In direct technique, the sinus approach is done directly through the superior, middle, or inferior lateral wall approach.

In the indirect technique, the sinus approach is through the crystal direction of the partially edentulous space.
The superior lateral approach of direct technique and crystal osteotome of indirect technique are the commonly followed techniques for sinus elevation.

Superior Lateral wall approach (Caldwell–Luc approach)

• The surgical approach is through the buccal surface of the edentulous site to gain access to the floor of the sinus raising the Schneiderian membrane
• The space thus created between the sinus floor and the Schneiderian membrane is filled with a suitable bone grafting material to obtain the desired bone dimensions
• The commonest postoperative complication is the tear of the sinus membrane which is repaired by stitching the membrane or restored by undisturbed healing for a period of 3–6 months for auto-repair.

Osteotome Technique

• With the crystal approach, crystal access to the floor of the sinus is obtained by implant drills or by other methods of osteotomy
• With suitable osteotomies, bone is compressed in incremental quantities through the osteotomy site towards the sinus floor elevating the Schneiderian membrane till the required amount of bone augmentation is done
• The procedure is completed with the implant insertion on the augmented site.

Important points to note

The healing time associated with sinus grafting is an average of 3–6 months. Complications, such as infection, inflammation, nerve damage, graft failure, oroantral communications, and implant loosening or implant failure, can occur.

Evidence-based data

The meta-analysis on sinus lift procedures by Stephen S Wallace and Stuart J Froum (2003)2concludes the following:

• The survival rate of implants placed in augmented sinuses varied between 61.7% and 100% with the average survival rate of all interventions being 92.6%
• Reports favored better implant survival rates in the non-grafted posterior maxilla
• Rough-surfaced implants have a higher survival rate than machine-surfaced implants when placed in grafted sinuses
• Particulate grafts show a higher survival rate than those placed in sinuses that had been augmented with block grafts
• A better prognosis is obtained when a membrane is used in covering the lateral window technique
• No statistical difference between delayed implant placement, types of rough-surfaced implants, length of follow-up, year of publication, and the evidence level of the study.

Implant site augmentation methods

Classified as

• Horizontal augmentation techniques
• Vertical augmentation techniques.

Minor bone deficiency areas are restored with guided bone regeneration materials with suitable alloplastic materials.

Major deficiency regions are restored by vertical or horizontal augmentation techniques in accordance to bone deficiency.

Horizontal Augmentation Techniques
Horizontal bone grafting is done by onlay and sandwich grafting.

Indication
Atrophy of the edentulous ridge with adequate residual height.

Contraindication

• Excessive inclination of the alveolar ridge
• The presence of bony undercuts is prone to fracture during the space creation.

Onlay grafting

Block autogenous bone, derived from other intraoral or extraoral sites, is placed in the deficient region, and secured with retrievable screws or resorbable materials.

Sandwich grafting

Space created is by splitting the bone between the cortical plates and filled with suitable augmentation materials. This technique is mainly indicated in the maxilla. It is difficult in the mandible due to the rigidity of the bone.

Vertical Augmentation Techniques

• The vertical bone height is achieved by securing the grafts with screws, plates or any retrievable materials
• The vertical augmentation technique is highly sensitive and the success rate is less compared to horizontal augmentation techniques
• The success rate depends on the site’s vascularity.

Vertical Distraction Osteogenesis

Increases the vertical height of bone by the process of slow distraction. Mostly done in the mandible.

Vertical Distraction Osteogenesis Indication

Insufficient vertical height with satisfactory residual width.

Vertical Distraction Osteogenesis Contraindications

• A severely deficient mandible has a high risk of fracture or neural damage
• Close proximity of the maxillary sinus
• Rigid palatal mucosa might reduce the distraction forces.

Soft tissue surgeries

• Are done for better esthetics
• Done either by respective surgery or by regenerative surgery
• The resective surgery corrects the irregular bone or the increased thickness keratinized gingiva. It is generally a final option to be adapted after attempting regenerative procedures in the management of implant failures.

Types of gingival graft surgeries

• Free gingival graft (FGG)
• Connective tissue graft (CTG)
• Pedicle grafts (PD) are the most commonly employed.

The FGG requires gingival tissue from a donor site whereas CTG requires a part of tissue from a flap.
The pedicle graft utilizes gingival tissue close to the required region.
The CTG is more efficient with encouraging results of root coverage and with lesser patient discomfort and postoperative complaints.
The FGG is a conventional and standardized procedure for increasing the thickness of attached gingiva where less than 2 mm of attached tissue is present. The FGG procedure reduces the frenum or muscular tension on the graft or the flap.