Table of Contents
Introduction:
Implant dentistry has evolved significantly with the development of various connection types, each offering unique advantages and challenges. Internal connection implants feature a socket-like interface that enhances stability and load distribution, leading to improved esthetic outcomes and reduced mechanical complications. Conversely, external connection implants, characterized by their protruding abutment, are often simpler to handle but may present higher risks of microbial contamination and mechanical issues. This article delves into the comparative benefits and drawbacks of internal versus external connection implants, aiming to provide a comprehensive overview to aid in clinical decision-making and optimize outcomes.
What Is a Dental Implant?
A dental implant is a prosthetic device that can be used to replace lost teeth and restore oral function. It contains three primary structures: the implant post, the abutment, and the dental crown. An abutment is a component that attaches the artificial tooth to the dental implant. The crown is specially crafted to fit the individual's mouth and match the natural color of their teeth. It mimics the appearance, feel, and function of real teeth. Below are the benefits of dental implants:
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They provide a more natural and comfortable feel.
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Have a higher success rate.
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Enhance chewing ability.
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Reduce the risk of cavities in adjacent teeth.
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Preserve bone structure at the site of the missing tooth.
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Minimize tooth sensitivity in nearby teeth.
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Do not require removal and cleaning each night.
What Factors Influence Successful Dental Implant Rehabilitation?
Implant dentists and maxillofacial surgeons should be aware that patients often have high expectations for both the appearance and function of their dental implants. While dental implants are considered superior to traditional crowns, bridges, or removable dentures for replacing missing teeth or restoring edentulous areas, not all patients are suitable candidates for them.
The success of dental implants relies on several factors, such as the patient's general health, the condition of the bone where the implant is inserted, and adherence to proper oral hygiene. With ongoing advancements in implant technology and techniques, dental implants have become a dependable and efficient solution for replacing missing teeth, significantly improving both functionality and quality of life.
Most individuals may prefer immediate loading of their dental implant prosthesis, rather than the traditional methods of delayed or two-stage loading, which occurs three to six months after implant placement. Although immediate dental rehabilitation using implants might seem ideal, it may not always be feasible due to various factors, particularly the individual’s local and systemic health. Individuals needing dental implants should adhere to strict oral hygiene protocols and attend regular dental check-ups to prevent postoperative complications. Additionally, considering the individual’s medical history and current health status is crucial, as these factors significantly impact oral wound healing and osseointegration, or bone implant fusion in the jaw.
Bone density is another important factor for the implant dentist or maxillofacial surgeon to consider during the preoperative evaluation phase. Only after assessing these factors and using modern radiographic imaging, such as cone beam computed tomography (CBCT) or multidetector CT (computed tomography) technology, can the implant dentist or maxillofacial surgeon make an informed decision about implant placement.
In most cases, the dentist can successfully rehabilitate the individual's jaw and meet their prosthesis expectations within 24 to 48 hours, allowing individuals to return to their normal social activities. This immediate rehabilitation typically depends on the type of implant-abutment connection used by the dentist.
What Is the Difference Between EHC and IHC Implant Structures?
Different dental operators may have varying opinions on the type of implant connection to use: the EHC (external hexagon connection), as seen in the original Branemark implants, or the modern IHC (internal hexagon connection) implants. Below is a comparison of these two types of implant-abutment connections and how they might affect the long-term success of dental implants.
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EHC Implants: They are traditional, first introduced with the Branemark system. They are still widely used, especially for full arch rehabilitation. These implants have a conical design with surfaces treated with zirconia oxide and often etched with mineral acids. The implant neck is typically machined to about 0.04 inches above the tissue surface. EHC implants feature an external hexagon with a diameter of 0.11 to 0.12 inches and a height of 0.03 to 0.04 inches.
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IHC Implants: They have an internal hexagon and no external hexagonal features, except for a small external collar to support the implant prosthesis. The internal hexagon design aims to offer improved stability and aesthetics.
Are IHC Implants Better Than EHC Implants?
According to current dental implant research, while it is claimed that internal hexagon connection implants may have fewer complications than external hexagon connection implants, scientific evidence is still needed to confirm this.
Common complications with external hexagon connection (EHC) implants include potential micromovements under high occlusal or masticatory (chewing) forces, which can lead to fatigue fractures of the implants. This issue arises from the EHC implant's reduced ability to handle masticatory movements effectively. Some studies also suggest a higher risk of bacterial leakage or contamination with external hexagon connections.
In contrast, internal hexagon connection (IHC) implants, which feature a small external connector to support the superstructure or implant prosthesis, are believed to better handle pressure and stress, particularly masticatory forces. Additionally, the platform shifting concept used in IHC implants, which involves using a smaller diameter abutment, may reduce bacterial leakage and decrease postoperative complications related to the soft tissue around the implant.
The choice between EHC and IHC implants may also be influenced by the specific clinical situation, such as the need for immediate load-bearing or the presence of complex anatomical structures. The implant’s compatibility with various prosthetic components and the surgeon’s familiarity with the implant system can also impact the decision.
Conclusion:
Although internal hexagon implants are considered better than external hexagon implants, the clinical decision should be made by the implant specialist or oral surgeon. Additionally, researchers have not observed any major differences in dental osseointegration (bone implant fusion) between these two types of abutment connections. The clinical success of dental implants largely depends on the patient’s local and systemic health factors, as well as bone density and the method used by the operator.
