Testing the Tools

  • by Ross Isbell, DMD, MBA
  • Sep 26, 2022
As I’m sure is the case for many general dentists, replacement of edentulous areas is a large part of my practice. I am increasingly replacing these areas with implant restorations. When dealing with larger or totally edentulous areas and designing a removable prosthetic’s implant anchorage with an individual attachment style, I typically gravitate toward these three systems.

Sterngold2 (3)Mini Implants That Can Make a Big Difference 
Sterngold MOR® Mini Implant System


If you are in a tough bone availability situation and do not have enough space for standard implants, mini implants are a great option. I began placing 3M minis years ago and have since transitioned to the Sterngold MOR® Mini Implant System. Personally, I only use these for attachment of removable devices, but they can be used for fixed applications as well. These implants are single stage, meaning that the abutment and body are joined and solid — there is no connecting abutment screw. That helps significantly with concerns regarding strength because, while they have less bone-to-implant interface or surface area, they also are not likely to bend with lateral forces even though they are under 3 millimeters in diameter. The abutment is shaped with a ball at the top and a cube at the bottom, with a flat circular platform extending out from the base of the cube and tapering into the implant body. When placing these, the goal is parallel body axes as with all overdenture systems, but it does allow for up to 30-degree maximum divergence. Since there is no abutment to change out, the angle of placement is final and not adjustable with custom designs. MOR implants are available in 2.1-, 2.4- and 3.0-mm diameters and 10-, 13-, 15- and 18-mm lengths. There are two housing options — rc-1 is the original style that allows for 30-degree divergence; rc-2 allows less divergence but has greater retentive forces. Both housing styles are about 4 mm in diameter and 4 mm deep and utilize a rubber O-ring to retain the ball-shaped head of the implant. I only use the 2.1 and 2.4 sizes because, if I am going larger than that, I would prefer the option of a changeable abutment and will place a standard implant. My favorite part about this system is the simplicity. First, identify the location for the implant. Confirm you have at least 10 mm of vertical space from anatomic issues with nerve or sinus. Palpate the ridge to confirm angulation and lack of concavities. Confirm you have 6 mm of tissue width, and, finally, record your measurements. Placement is completed by punching a hole using the 1.1-mm pilot drill to depth, confirming you did not puncture through bone using a probe, then placing and hand torquing an implant with a wing driver until you reach tissue height with the flat bottom platform. If you have less than 6 mm width, I would recommend flapping instead of punching to confirm you have at least a 4-mm bone platform. Lastly, to pick up the housing, hollow out enough space in the prosthetic to allow seating without bumping the implant and fill the hollow area with a soft reline material such as Tokuyama’s Sofreliner® on the day of surgery. After 4–6 months, bring the patient back to pick up the housing with your choice of acrylic or pickup material. In situations where nothing else will fit, mini dental implants, specifically the MOR system, are a game changer for prosthetic retention.

BioHorizonsWhen You Need Extended Range 
OD Secure Tapered Implants


For standard-sized implants, my preference is the BioHorizons® tapered internal. I like them for a lot of reasons, especially their OD Secure system for attaching to removable prosthetics. Color-coded to match the size of the implant platform they are paired with, they are similar in shape to the Zest LOCATOR® system, with a circularly shaped semi-precision attachment. Where they are different is that the top attachment is designed to fit with a standard 0.50 driver for placement and torquing, so your standard prosthetic kit is already equipped for this. Also, the housings are only 4 millimeters in diameter and 2 mm high, so they take up less space in the intaglio of the prosthetic. To me, this means that they can fit in tighter vertical spaces and require less hollowing of preset acrylic. The housings are designed to fit tight but still have a total range of divergence up to 50 degrees. They also have a color-coded semi-precision attachment system — but only have the circular shape and do not use the donut design. Lastly, the fit of the abutments-implant interface to BioHorizons implants appears tighter and more precise on radiographs, likely due to the fact that it is OEM compared to a third-party manufacturer. This is a solid overdenture solution and my choice when I need extended range.

zest (1)A Tried-and-True Implant System 
LOCATOR® Overdenture Implant System

Zest Dental Solutions 

For the majority of my cases, I keep it standard and simple and use the LOCATOR® Overdenture Implant System (LODI) by Zest. This tried-and-true product is the most used and most universal snap-on attachment system. There is a locator for pretty much every type and size of implant (280 types currently), and they all fit to a single type of housing. The housing style is a simple cylinder/bowl shape approximately 5 millimeters in diameter and 3 mm deep that retains a plastic insert either in the same cylinder shape (extended range) or with a center protrusion resembling a donut (standard). These plastic attachments are color-coded to indicate their flexibility and corresponding attachment strength. The standard attachments have an allowance of 20 degrees of total angular divergence between implant axes and up to 40 degrees with the extended range. However, Zest has also recently come out with a further extended range housing system called LOCATOR R-Tx. This housing contains two separate levels of cylinder so that implants with similar divergence angles can achieve an even tighter fit after snapping into two levels. The first level feels and fits like the original system and helps guide into place, and the second level makes for greatly increased security. While there are options to include Zest locators into bars and with multi-unit abutments, there isn’t really a solution for correcting angulation of the abutment, just for compensating using the semi-precision plastic attachment within the housing. Due to its widespread usage and the company’s history of quality, I feel like using a Zest system is the best option for most patients because the abutments and housings will last decades, and the attachments will last at least a year, if not two. This also makes it simple for the patient and whoever their next doctor may be (assuming it’s not me) to perform maintenance and part replacement. Primary data that needs to be collected to order these abutments includes gingival height and implant type and size so that your rep can ensure you have enough supragingival space for attachment. Placing the abutments is simple, but it does require use of Zest’s proprietary three-in-one driver due to the triangular shape of the coronal aspect. It is a well-built driver for hand-torquing abutments in place, has the ability to be wrench-torqued with a 0.50 driver, and has an attachment end for placing and removing the semi-precision attachments. If you are able to judge angulation, you can choose which of the systems you want, but, for the majority of my cases, I use the standard LODI system.

Ross Isbell, DMD, MBA, currently practices in Gadsden, Alabama, with his father, Gordon Isbell, DMD, MAGD. He attended the University of Alabama at Birmingham (UAB) School of Dentistry and completed a general practice residency at UAB Hospital. Isbell has confirmed to AGD that he has not received any remuneration from the manufacturers of the products reviewed or their affiliates for the past three years. All reviews are the opinions of the author and are not shared or endorsed by AGD Impact or AGD. To comment on this article, email impact@agd.org.