Tooth whitening remains one of the most frequently requested esthetic dental procedures; however, predictable outcomes depend heavily on patient-specific factors such as enamel condition, type of discoloration, medication history, and selection of the whitening modality. Isotretinoin, a systemic retinoid medication commonly prescribed for severe acne, has been associated with xerostomia, enamel dehydration, reduced translucency, and intrinsic gray discoloration patterns that often respond poorly to conventional whitening approaches.
Custom whitening trays offer several advantages over stock trays, including improved adaptation to the dentition, reduced gingival exposure to whitening agents, enhanced patient comfort, and more consistent gel distribution.
This clinical case review presents a 46-year-old patient with a history of prolonged isotretinoin therapy who exhibited a flat gray hue and irregular white opacities. Initial in-office whitening resulted in minimal improvement, prompting a digitally guided take-home whitening approach. A customized whitening tray was fabricated using digital scanning and 3D printing, allowing precise adaptation, improved gel containment, and consistent contact between the whitening agent and enamel surfaces. Extended overnight whitening with 16% carbamide peroxide produced gradual and clinically significant improvement. This case highlights the clinical value of digitally fabricated whitening trays for managing complex intrinsic discoloration cases.
Advancements in whitening materials, digital dentistry, and additive manufacturing have significantly expanded treatment options for esthetic dental patients. While in-office whitening procedures remain effective for many extrinsic and mild intrinsic discolorations, dentist-supervised take-home whitening systems allow prolonged exposure to peroxide-based agents and frequently provide superior outcomes in more complex cases.1 The success of whitening therapy depends on accurate diagnosis of discoloration etiology, recognition of enamel and dentin optical properties, and selection of a delivery system capable of maintaining consistent contact between the whitening agent and tooth structure.
Intrinsic gray discoloration represents one of the most challenging whitening presentations. Gray discolorations are often associated with reduced enamel translucency and dehydration, which limit peroxide diffusion and delay visible shade change. These cases frequently demonstrate minimal response to short-duration, high-concentration in-office whitening protocols alone. Predictable improvement often requires extended exposure to carbamide peroxide delivered through precisely adapted trays, which allow sustained contact between the whitening agent and enamel surfaces.
Clinical Background
Isotretinoin is an oral retinoid medication most commonly prescribed for the treatment of severe cystic acne and other dermatologic conditions. While highly effective, isotretinoin therapy has been associated with systemic side effects including decreased salivary flow, mucosal dryness, and altered oral tissue hydration.
As described in Bleaching Techniques in Restorative Dentistry, dehydrated and medication-affected enamel structures demonstrate reduced responsiveness to rapid whitening techniques.2 In addition, irregular white opacities may become more pronounced as enamel hydration fluctuates, further complicating esthetic outcomes. Patients with these characteristics often report minimal improvement with over-the-counter whitening products, and even professionally administered in-office whitening may yield limited shade change. In such cases, extended whitening protocols delivered via well-fitting trays are frequently required.1
Case Presentation
A 46-year-old female patient presented with dissatisfaction regarding uneven tooth coloration and a progressively worsening flat gray appearance over the previous decade. She reported increasing dullness and lack of brightness despite good oral hygiene and routine dental care. Her medical history was significant for more than 10 years of continuous isotretinoin therapy.
Clinical examination revealed generalized intrinsic gray discoloration affecting the maxillary and mandibular anterior dentition, accompanied by irregular white opacities and visibly dehydrated enamel surfaces. These findings were consistent with resistant intrinsic discoloration patterns described in the whitening literature.2,3 Pretreatment and post–in-office whitening photographs were obtained to evaluate the immediate response before initiating the extended take-home whitening protocol.
Pre-Operative Shade Assessment
Pre-operative shade assessment was performed prior to initiation of whitening therapy to establish a baseline and document the extent of intrinsic discoloration. A full-face pre-operative photograph was obtained to evaluate smile dynamics and overall facial presentation (Figure 1). Retracted intraoral photography revealed generalized intrinsic gray discoloration with an initial shade assessment of B1 (Figure 2).
Shade confirmation was performed using the EyeSpecial C-V camera (Shofu Dental Corporation, San Marcos, California) in isolate shade mode to eliminate background color interference and objectively confirm baseline shade (Figure 3). Despite the B1 designation, the enamel exhibited reduced translucency and flat gray optical characteristics consistent with dehydrated enamel described in the whitening literature.2 Following completion of in-office whitening, minimal perceptible shade shift was observed, further supporting the need for an extended take-home approach.
Digital Scanning and Design Workflow
A full-arch digital impression was obtained using the iTero Element scanner (Align Technology, Tempe, Arizona), capturing detailed enamel morphology, embrasures, and gingival margins. Digital scanning eliminated distortions associated with traditional impression materials and produced accurate STL files for both the maxillary and mandibular arches (Figure 4 and Figure 5).
The STL files were imported into DentaMile connect software (DMG America, Ridgefield Park, New Jersey), where patient information was entered and linked to the digital models to ensure accurate case management and workflow continuity (Figure 6). Gingival margins were digitally identified, and tray borders were established to balance patient comfort with whitening gel containment.
Internal reservoirs were digitally designed on both the mandibular and maxillary whitening trays to create controlled pockets on the facial surface of the teeth, in order to help retain the whitening material against the enamel surface and enhance prolonged contact time (Figure 7). Once margin lines were finalized, the tray design was approved and submitted to the 3D printer for fabrication (Figure 8). Digital design ensured uniform thickness and eliminated inconsistencies inherent in traditional vacuum-formed trays.4
3D Printing, Washing, and Finishing
The whitening trays were fabricated using the DentaMile Desk MC-5 DLP printer (DMG America), which employs a high-resolution light-curing additive manufacturing process to produce precise, uniform appliances. Upon completion of the print cycle, the whitening tray was carefully removed from the printer build platform and inspected for dimensional accuracy and surface integrity (Figure 9).
Post-printing cleaning was performed, ensuring thorough removal of residual uncured resin and promoting
biocompatibility (Figure 10). After washing, the trays underwent final curing according to manufacturer guidelines to complete polymerization and optimize material strength, clarity, and flexibility. The finished maxillary whitening tray demonstrated excellent adaptation, smooth margins, and appropriate elastic memory for repeated insertion and removal.
Take-Home Whitening Protocol
The patient was prescribed a take-home whitening regimen utilizing VivaStyle (Ivoclar, Schaan, Liechtenstein) take-home whitening gel containing 16% carbamide peroxide. The patient was instructed to wear the customized whitening trays overnight while sleeping for 14 consecutive days.
Extended overnight wear allowed gradual peroxide diffusion through enamel and dentin, aligning with whitening principles described for the management of resistant intrinsic discoloration.1,5 The precise fit of the digitally fabricated trays promoted even gel distribution, minimized soft tissue exposure, and contributed to excellent patient compliance throughout the treatment period.
Results and Discussion
Progressive improvement was observed throughout the whitening protocol. The dominant gray hue softened gradually, and irregular white opacities blended more uniformly with surrounding enamel. The final smile demonstrated improved value, brightness, and translucency following completion of the 14-day whitening protocol (Figure 11). Comparative retracted images of the smile illustrate these treatment results, showing the pre-treatment appearance with intrinsic gray discoloration and the post-treatment appearance with improved brightness and translucency following the take-home whitening protocol (Figure 12 and Figure 13). Assessment of the final tooth shade demonstrated a shift to OM3, indicating effective whitening following completion of the therapy (Figure 14).
These findings are consistent with previously published observations that intrinsic gray discolorations require prolonged whitening exposure and meticulous tray adaptation to achieve predictable results.1,2 Digital scanning, software-based design, and additive manufacturing addressed common limitations of conventional tray fabrication, including inconsistent thickness, poor adaptation, and uneven gel retention. Similar outcomes have been reported in prior clinical publications which emphasize the importance of customized tray design and extended whitening protocols in managing resistant discoloration cases.4,6
Conclusion
The integration of digital scanning, software design, and 3D printing provides a precise, efficient, and patient-centered approach to whitening tray fabrication. In patients presenting with intrinsic gray discoloration associated with long-term isotretinoin therapy, this digitally guided workflow supports extended take-home whitening protocols that align with established whitening principles described in the literature.1,2,5 Digitally fabricated whitening trays represent a valuable clinical solution for managing resistant discoloration in contemporary aesthetic dentistry.
References
1. Haywood VB. Principles of Extended TakeHome Whitening. London, United Kingdom: Quintessence Publishing; 2011.
2. Greenwall L. Bleaching Techniques in Restorative Dentistry: An Illustrated Guide. London: Martin Dunitz/CRC Press; 2001.
3. Sulieman M. Classification and management of tooth discoloration. Dent Update. 2005;32(8):463468. doi:10.12968/denu.2005.32.8.463.
4. Brinker SL, Pace S. Digital workflows for customized whitening tray fabrication. Dent Prod Rep. 2021.
5. Greenwall L. Clinical challenges in whitening-resistant enamel. Int Dent Rev. 2020.
6. Brinker SP. Clinical considerations for managing resistant intrinsic tooth discoloration. Dent Prod Rep. 2019.
Figures and Images
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Shannon Pace Brinker, CDA
