Immediate Loading Protocols for Dental Implants: A Systematic Review

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International Journal of Medical Science and Current Research (IJMSCR)

Available online at: www.ijmscr.com

Volume1, Issue 1,Page No: 134-139

May-June 2018

134 Immediate Loading Protocols for Dental Implants: A Systematic Review

Dr. Mayank Shah

Reader, Department of Prosthodontics, Awadh Dental College and Hospital, Jharkand-India

Corresponding Author:

* Dr. Mayank Shah, Reader, Department of Prosthodontics,

Awadh Dental College And Hospital, NH-33,Danga,P.O. Bhilaipahari, Jamshedpur-831012,India

Type of Publication: Original Research Paper Conflicts of Interest: Nil

ABSTRACT

Dental implants have been around for over 40 years and have revolutionized the dental profession. Many have different views while loading the implants in the oral cavity. Initially the delayed loading of implants was thought to be the only method of loading of fixed implant. The current trend is moving towards the immediate loading of fixed implant retained prostheses. Immediate loading of dental implants offers many advantages to the patient as well as the dentist. It allows for a single stage surgery, thereby avoiding the physical trauma and chair time of the uncovering procedure, and esthetics and function can be immediately restored. Immediate loading shortens the total rehabilitation time, with increasing patient satisfaction, and it avoids the delays in the final rehabilitation and the difficulty of wearing a conventional denture during the healing phase. Despite an increasing number of publications on immediate and early loading of dental implants in completely edentulous patients, that report high survival rates for the immediate loaded implants. The controversy still exists over the reliability of the reported data, because frequently the publications are of insufficient methodological quality such as insufficient follow- up, inadequate sample size, absence of randomization, lack of well-defined exclusion and inclusion criteria, lack of well-defined success criteria, etc.

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Keywords: Dental Implants, Early Loading, Immediate Loading, Osseointegration, Teeth in a day.

INTRODUCTION

Immediate loading on implants at present is gaining a lot of importance due to various reasons. In the last two decades, it became clear that clinical implantology had advanced to the point that this treatment represented a predictable approach to the replacement of lost teeth. As initially introduced a complete surgical protocol was required, with the implants submerged in the soft tissue and alveolar bone, to allow for healing without loading followed by surgical uncovering of restoration 3 to 6 months

later.1,2,3 Per-Ingvar Branemark, a Swedish physician

developed this 2-stage protocol based on meticulous

research conducted over a 20-year period.

Branemark estimated that implants placed with this protocol had "an expected function time of several decades – perhaps 50 years".2,3

Later, evidence was beginning to suggest that a one stage protocol might offer patients the prospect of

expected dental rehabilitation.4 In 1993, the authors

initiated a study in which they immediately loaded 40

Branemark implants placed in conjunction with 90 unloaded implants in 10 edentulous mandibles. Although some (20%) implants were lost, all of the

patients successfully retained their prostheses.1,5,6,7

EVOLUTION OF CONCEPT OF IMPLANT LOADING

About 25 years ago, Branemark et al. published the first long-term follow-up on oral implant, providing

the scientific foundation of modern dental

Implantology.8 The predictability of implant

The rationale for such a long delayed loading period was that the premature loading may lead to fibrous tissue encapsulation instead of direct bone apposition and the necrotic bone at the implant bed border is not capable of load bearing and must be first replaced by new bone. Also rapid remodeling of the dead bone layer compromises the strength of the ossesous tissue supporting the bone-implant interface and the integrity of the periosteal margin may be threatened by undermining remodeling of adjacent bone during late healing period. 2,3,16,17,18

CIRCUMSTANCES SURROUNDING

BRANEMARK’S RESULTS

They concluded that “a minimum healing period of 3 months is required, otherwise the risk of immediate or late implant mobility greatly increases” was in retrospection however drawn from particularly

demanding clinical conditions involving

simultaneously.

PATIENT SELECTION WITH POOR

QUALITY AND QUANTITY BONE

In Branemark’s protocol, patient selection was “a negative selection with patients exhibiting an extremely resorbed jawbone of often low mechanical strength” where 10% had moderate bone resorption, 80% had advance resorption and 10% had extreme resorption. These patients had “often a fairly thin cortex with a central marrow space, containing few

osseous trabeculae providing less favorable

mechanical retention of the implant”. It is presently admitted that bone quality is a critical parameter for implant prognosis. Higher failure rates were recorded for submerged implants inserted in recipient sites with thin cortical bone. Therefore, the patient population that led to the requirement of a minimum of 3-6 months of delayed loading did not represent a patient pool with good bone conditions, e.g. type I or

II where a thick cortical bone is present.3,4

NON-OPTIMIZED IMPLANT DESIGN

Implant design differed from present Branemark implant in dimension and design since “standard dimensions and proportions were established from

the routine period and onwards”. Before the routine period, up to 22 implant designs were tried and abandoned. It was concluded that the various implant designs that led to the requirement of a minimum of

3-6 months of delayed loading were not optimized. 3,4

SHORT IMPLANTS

When short fixtures were placed rather superficially the covering bone was often fairly thin especially marginally. In the routine procedure, long fixtures were used which were also inserted deeper within the jawbone. This means that there was considerably more bone tissue surrounding the implant at installation presently, it has been documented that

length is a critical parameter for implant integration.4

NON-OPTIMIZED SURGICAL PLACEMENT The surgical protocol was not optimal as “continuous

adjustments and modifications of therapeutic

procedures” occurred. Previously, “fairly extensive muco-periosteal flaps” were raised. This approach especially deprived and delayed bone healing. Reduced bone exposure led to less post – operative complications and enhanced bone healing cortical bone jaw from part of its periosteal vascular supply” and delayed bone healing. Reduced bone exposure led to less post-operative complications and enhanced

bone healing. 4

NON-OPTIMIZED SURGICAL TECHNIQUE

In addition, tapping was a part of the surgical protocol. Tapping affects the holding power of screw implants. This has been confirmed by Schnitman et al and Salama et al, in their immediate loading protocols, which reduced or avoided tapping, in order

to provide the best primary stability. 5

BIOMECHANICALLY DEMANDING

PROSTHESIS

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requirement of a minimum of 3-6 months of delayed

loading was very demanding. 4,5

NEED FOR RE-EVALUATION OF

BRANEMARK PROTOCOL

The reasons to reevaluate the mandatory aspect of a long delayed loading period are consideration given to the specifically demanding conditions met during the original Branemark follow-up, loading per se does not impede the healing process to occur and prematurely loaded implants are capable of clinical integration as demonstrated in several experimental studies.19-22

IMMEDIATE FUNCTIONAL LOADING

This technique of placing Implants in a single surgical step involves fitting the prosthesis in the same surgical session. According to some it may be delayed by up to 3 days post-surgery. The Provisional restoration delivered is in full occlusal contact with the opposing dentition. The advantage of this method in addition to the surgery taking place in single step, is the immediate fitting of the final prosthesis and the patient’s failure to experience any functional & psychological discomfort associated with being edentulous (with or without removable prostheses). In case of removable prostheses, the protocol essentially involves placement of 4 implants in the mandibular interforaminal region, each of at least 10 mm length to achieve bicortical anchorage

and splinted to each other by a U shaped bar. 22-24

The more recent Novum technique by Branemark involves the use of prefabricated components and insertion of the final permanent prosthesis on the day of surgery.For fixed prostheses, the technique involves a few fixtures that are allowed to heal by submerge Branemark’s protocol (Primary Implants) while a few are used to support the fixed provisional

prosthesis (Secondary Implants).25

Secondary Implants are considered “disposable fixtures” i.e. they are supposed to support the temporary prosthesis until the primary implants have gone through the healing stage successfully. If the excessive loading subjected to these implants, during the healing phase, impairs, osseointegration, they are eliminated. If not an assessment is made regarding theirinclusion in the final prosthesis. This technique is not commonly used in completely edentulous jaws.26,27

IMMEDIATE NON-FUNCTIONAL LOADING

This technique brings together the advantages of one stage implants and immediate loading. The provisional prostheses are not in occlusion and therefore serve only aesthetic purpose. This idea can be used when all centric and lateral occlusal contacts are with natural teeth or well integrated and healed

implants.28 As compared with immediate functional

loading, this method has the advantages of reducing the risk of biomechanical functional overloading. Even if the patient chews on the provisional prosthesis (while nevertheless encouraged to follow a soft food diet and avoid implant sites as far as possible) the forces generated during chewing are less than 30 lbs/sq. inch and for less than 30 minutes a day. This technique is especially useful in the

anterior region.29-31

INDICATIONS AND CONTRAINDICATIONS FOR IMMEDIATE LOADING

The immediate loading protocol can be used for replacement of single tooth, partial and complete

edentulism.32,33 The contraindications for immediate

loading are patients who are bruxers, edentulous patients with a reduced bone quality and quantity, with not optimized biomechanically suprastructures

and with short implant lengths.12 Older style implants

may require anywhere from five months to 2 years to

receive new tooth.34

ADVANTAGES AND DISADVANTAGES OF IMMEDIATE LOADING

The advantages of immediate loading are functional and aesthetic needs of the patient within few hours. Very little discomfort is associated with the procedure and in fact some people have reported almost no pain at all.This procedure is less invasive than some older procedures for crown and bridge placement, where perfectly good neighboring teeth have to be ground down to accommodate the crown. No second stage surgery or any additional appointments are required and fear of long term

edentulism is eliminated.20,35,36

FUNCTIONAL LOADING OF DENTAL

IMPLANTS: “TEETH IN A DAY”

Recognizing the significant advantage offered by immediate loading, the authors have developed “Teeth in a day” protocol. This protocol is best accomplished by a Prosthodontist who surgically places dental implants or by a surgical and prosthodontic team working in the same facility.

The Prosthodontist fabricates a provisional

restoration prior to surgery and then uses a series of drills with copious irrigation to create an intimate implant receptor site. During creation of the osteotomy; bone quality and quantity at the site are assessed. If deemed sufficient to allow for good initial stability, one or more implants are placed. Selection of optimal implant diameters and thread design as well as self-tapping the implants may enable the operator to further increase the initial

stability of the implant. 38

Immediately after the last implant is placed teeth in a day restoration is created by converting a previously constructed provisional prosthesis into an immediate implant support non-removable prosthesis. While this

conversion is occurring in the laboratory, the abutments and prosthetic cylinders are connected to the implants. The prosthetic cylinders are connected to the implants. The prosthetic cylinders are then affixed to the provisional restoration intraorally using autopolymerizing acrylic resin. This technique allows the placement of the implants in the proper position for each individual patient, followed by settlement of the provisional restoration before

surgical flap closure.39,40

CONCLUSION

The question of whether to load an implant immediately or not has prompted extensive research. Although there is more or less a general consensus that the 2-stage protocol can be replaced by the single stage Immediate Loading Protocol, caution needs to be exercised during patient selection. Appropriate patient selection remains critical candidates for this procedure must have a sufficient quality and quantity of bone in order to ensure initial fixation. They also need to be conscientious about following all post-surgical instructions where these elements are present, however, the teeth in a day; time protocol holds the promise of significantly expanding the number of individuals who are willing and able to reap the rewards of implant dentistry.

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