Perry E. Jones, DDS, FAGD

Align Technology has delivered significant technology advances, represented by the Invisalign clear aligner products. With these solutions, my patients and practice have gained tremendous benefits, both in terms of clinical application and profitability. However until recently, achieving highly accurate impressions for optimizing aligner benefits has been challenging. Various impression materials have their drawbacks, process inconsistencies often led to additional patient appointments and adjustments, and the entire experience was often unpleasant for both patient and doctor.

Today, digital impressions, such as those delivered by the Align iTero™ scanner, provide my practice with superior accuracy, cost savings, patient satisfaction, restorative solutions and orthodontic application, as well as supporting multiple practical uses of polyurethane models.

Accuracy optimizes results and efficiency


	Accuracy is essential to optimizing clinical results and efficiency, yet producing an accurate replica of the teeth has been a huge clinical challenge. Varying impression materials, including plaster, rubber base material, polyether, reversible hydrocolloid and PVS material have unique properties and idiosyncrasies, which make it difficult for dentists to produce consistently outstanding results. For example, impression taking with PVS is prone to pulls and tears; bubbles and voids; distortion; tray and tooth contact; poor tray bond; delamination; sensitivities to temperature, technique, time and chemistry; varying shrinkage; stone model pouring; and die trimming discrepancies.

The Align iTero scanning technology eliminates these issues. It doesn’t require any powder, powder dusting, or accent frosting-no matter the type of scan or restoration desired. Full arch scanning and detailed coronal reproduction required for Invisalign submission requires a high-quality scan with interproximal detail and high accuracy. The iTero powder-free technology delivers accurate digital impressions of the interproximal areas and ensures arch width dimensional stability.

Accurate reproduction of the coronal portion of the teeth usually requires retakes. Studies indicate that about one-third of dentists retake impressions three or more times per month, and on average, one-third of dentists reappoint patient impression-taking at least once a month. iTero optical scanning eliminates retakes. Scans can be reviewed in real time, and tools such as an “eraser” aid scan accuracy. All of these features assist us with providing our patients with shorter seating times for the final restoration and eliminating time-consuming patient recalls to retake impressions.


	There are two different digital scanning technologies available to the dental industry: parallel/confocal and triangulation/sampling scanning. The iTero scanner’s parallel/confocal scanning technology uses laser and optical scanning to digitally capture teeth and gingival surfaces and contours. iTero captures 100,000 points of laser light in perfect focus at 300 focal depths. In contrast, triangulation/sampling technology requires a powder coating and applies one angled cone of light to capture a single image at 15,000 microns.

Powderless scanning and 360° visualization capabilities enable iTero to operate with surface contact in the scanning technique for accurate digital impressions. Accompanying analytical tools also enable dentists to measure and verify design preparation. The doctor can use the scanner for almost any restorative procedure, select the desired restoration material, and send the scan to a lab of choice. The iTero 4.0 software seems to produce a noticeably better aligner fit (Fig. 1). This observation was further supported by a 2011 study, which found that seven times fewer fit issues occurred with scanning versus PVS impressions.


	Traditional impression-taking techniques are unpleasant at best. Patients object to the taste, tray size, bulky material, and the common gag reflex. Digital scanning eliminates all of these objections. In addition, iTero scanning enhances patient communication because patients can see their dentition. The images are “cleaned” by the software and a very neat “soaped” model appears on the screen (Fig. 2). iTero software significantly accelerates the ClinCheck treatment plan, which has greatly improved patient acceptance and communication.


	Practice productivity is increased because records and submission time are accelerated. For restorative productivity, restoration delivery time is reduced by about 50%, because of the iTero scanning accuracy and predictability. The iTero scanner is also cost effective. For example, if we assume $500 of hourly production, an average 15 minutes of chairtime savings is $125 per production hour. We can assume only one scan restoration perday and a conservative estimate of 120 production days per year for savings of $12,500 to $16,250 per year. Even with a conservative practice model, one can see the technology costs are offset by the projected time savings.


	Digital scanning with iTero provides an open platform for creating highly accurate polyurethane models, instead of stone models, that any dental laboratory can use to create any indirect restoration. Current advances in laboratory technology also can use scanned data with CAD/CAM systems to produce modelless milled ceramic restorations. The absence of stone modeling offers a further cost offset versus conventional lab costs.

In addition, digital scanning has advanced implant practice integration. iTero 4.0 software allows the use of purpose-made scan abutments. Laboratories such as Glidewell offer a library of different virtual implant fixtures that can be used with CAD/CAM to create custom ceramic abutments, as well as ceramic final restorations, on a virtual platform with modellless milled ceramic restorations. Software development now enables merging of CBCT DICOM files with Align STL files to offer surgical guides developed with simultaneous consideration of hard tissue and optimal implant restoration location.

Digital scanning with the Align iTero system has greatly enhanced clinical accuracy, productivity and flexibility for a wide range of alignment and restorative procedures. It is difficult to imagine our office without it.

Articles

Align Technology has delivered significant technology advances, represented by the Invisalign clear aligner products. With these solutions, my patients and practice have gained tremendous benefits, both in terms of clinical application and profitability. However until recently, achieving highly accurate impressions for optimizing aligner benefits has been challenging.