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Write a note on bed assessment of phd study on occlusal splint and why the study was conducted and how it strengthens the novelty of my phd study on comparison of fabrication of occlusal splints fabricated by conventional technique, sla 3d printed and milled , and invitro study

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Here is a comprehensive Need Assessment Note for your PhD study:

Need Assessment for PhD Study:

Comparative Evaluation of Occlusal Splints Fabricated by Conventional Technique, SLA 3D Printing, and CAD/CAM Milling — An In Vitro Study

1. Background and Clinical Significance of Occlusal Splints

Occlusal splints (also termed stabilization splints, Michigan splints, or night guards) are removable intraoral appliances placed over the occlusal surfaces of teeth. They are among the most widely prescribed and clinically validated devices in contemporary dental practice, used principally for the management of:
  • Temporomandibular disorders (TMD) — a cluster of musculoskeletal and neuromuscular conditions affecting the temporomandibular joint, masticatory muscles, and associated structures
  • Bruxism — parafunctional grinding and clenching with a reported prevalence of 8–31% in the general population
  • Occlusal instability, dental attrition, and tooth wear protection
  • Pre-prosthetic occlusal rehabilitation as a diagnostic and therapeutic tool
The high clinical burden of TMD and bruxism globally establishes occlusal splints as a critical appliance of relevance to both specialist and general dental practice. A systematic review (Chahrour & Reda, 2025 [PMID: 40951096]) reaffirmed the central role of occlusal splints as a standalone, conservative, and reversible intervention in TMD management. The prevalence of these conditions necessitates an appliance that is not only effective clinically but also accurate, durable, and practically fabricable.

2. Limitations of the Conventional Fabrication Technique — The Clinical Problem

For decades, occlusal splints have been fabricated by the conventional technique — involving impression-taking, pouring of stone casts, vacuum-forming or heat-cured polymethylmethacrylate (PMMA) processing, followed by extensive chairside adjustments. While well-established, this workflow carries several well-documented drawbacks:
  • Dimensional inaccuracy and distortion during polymerization of heat-cured acrylic
  • Operator-dependent variability in fitting, occlusal adjustment, and finishing
  • Multiple clinical appointments, increasing patient burden and chair time
  • Porosity and surface irregularities in conventionally processed PMMA, predisposing to bacterial colonization
  • Residual monomer release with associated biocompatibility concerns
  • Lack of digital archiving, precluding easy duplication or modification of the appliance
These limitations create a compelling rationale for investigating alternative, digitally driven fabrication methods.

3. The Shift to Digital Fabrication — The Research Context

The rapid integration of computer-aided design and computer-aided manufacturing (CAD/CAM) technology in dentistry has introduced two principal digital fabrication pathways for occlusal splints:

3.1 CAD/CAM Milling (Subtractive Manufacturing)

Milling involves the computer-guided machining of pre-polymerized PMMA blocks (e.g., Kerox Premia, ProArt CAD Splint, Ivoclar) using multi-axis milling units. Milled PMMA offers:
  • High density and homogeneity due to industrial polymerization
  • Superior mechanical properties compared to conventional PMMA
  • Reproducibility and dimensional precision
A 2026 in vitro study (Aminuddin & Petridis, [PMID: 42035479]) confirmed that milled PMMA showed the highest flexural strength (115.5 ± 5.3 MPa), lowest monomer release, and lowest wear volume loss among all three fabrication methods — positioning it as mechanically superior.

3.2 SLA 3D Printing (Additive Manufacturing)

Stereolithography (SLA) builds the appliance layer-by-layer through photopolymerization of liquid resin. Dedicated splint resins (e.g., FreePrint Splint 2.0, KeySplint Hard) are now commercially available. SLA printing offers:
  • Complex geometry reproduction with high resolution
  • Minimal material wastage
  • Rapid turnaround and scalability
  • Potential for fully in-office digital workflows
However, SLA-printed splints demonstrate inferior flexural strength and higher wear compared to milled and conventional PMMA (Aminuddin & Petridis, 2026), and printing angle has been shown to significantly influence mechanical performance. Monomer release from printed resins (e.g., KeySplint Hard: 29.7 ± 3.6 ppm) also warrants further biocompatibility scrutiny.

4. Identified Research Gaps — The Need for Your Study

A critical review of the existing literature reveals the following gaps that directly justify your PhD study:

Gap 1: Narrow Scope of Existing Comparative Studies

Most published studies compare only one or two mechanical properties (e.g., flexural strength alone, or wear alone) across fabrication methods. A multi-parameter, head-to-head in vitro comparison covering surface hardness, fit accuracy/trueness, surface roughness, flexural strength, and wear simultaneously across all three methods — conventional, SLA, and milled — is lacking.

Gap 2: Retention Has Been Studied, But Not Comprehensively Linked to Fit Accuracy

Assiri et al. (2025, [PMID: 40254853]) demonstrated that conventional splints showed the highest retentive force (16.4 ± 4.94 N), significantly greater than milled (6.42 N) and 3D-printed (4.42 N) splints. However, the study acknowledged that retention may be influenced by marginal fit and surface adaptation — parameters not simultaneously measured. Your study bridges this mechanistic gap by evaluating fabrication-related dimensional accuracy alongside mechanical outcomes.

Gap 3: SLA-Specific Parameters Remain Undercharacterized

While fused deposition modeling (FDM) and DLP 3D-printed splints have received attention, SLA-specific comparisons — including the effect of post-curing protocols, layer orientation, and SLA resin chemistry on splint performance — remain sparse in the direct three-way comparison literature.

Gap 4: Comprehensive In Vitro Methodology Lacking

Arreaza et al. (2026, [PMID: 41233246]) studied wear behavior against multiple antagonist materials in vitro but did not incorporate conventional vs. digital accuracy assessments or surface property profiling. Your study adopts a broader in vitro framework that simulates real-world clinical performance more holistically.

Gap 5: No Standardized Framework for Fabrication Method Selection

Clinicians currently lack evidence-based guidance on which fabrication method to choose for a given clinical scenario (cost, time, mechanical performance, fit, biocompatibility). Your study directly generates this decision-support evidence.

5. Why the Study Was Conducted — Rationale

Your PhD study was undertaken to address the following evidence-based imperatives:
  1. Clinical demand for optimized splint performance: Given the high prevalence of bruxism and TMD, even small improvements in splint accuracy, durability, and patient comfort have significant aggregate clinical impact.
  2. Democratization of digital workflows: SLA printers are increasingly accessible to dental laboratories and clinics. Before widespread adoption, rigorous comparative in vitro evidence is needed to validate their performance against established standards.
  3. Lack of head-to-head three-way comparison: The literature has progressively added digital comparators, but a simultaneous, standardized three-arm in vitro study evaluating conventional, SLA, and milled splints across multiple outcome parameters had not been comprehensively conducted at the time of study conception.
  4. Material diversity and lack of standardization: The commercial landscape for 3D printing resins and milling blanks has expanded rapidly, with variable properties across products. Establishing a baseline comparative framework using standardized materials and methods provides reproducible reference data.
  5. Academic and translational value: The in vitro design allows controlled measurement of fabrication-related variables, isolating material and process effects free from confounders inherent in clinical studies (patient biology, compliance, operator variation).

6. How Existing Literature Strengthens the Novelty of Your Study

The following framework demonstrates how current published studies validate your study design while simultaneously exposing gaps that only your research fills:
Published StudyWhat It FoundWhat It Missed (Your Novelty)
Assiri et al., 2025 (PMID: 40254853)Retention: Conventional > Milled > 3D-printedDid not assess dimensional fit, surface hardness, or roughness
Aminuddin & Petridis, 2026 (PMID: 42035479)Milled PMMA: highest flexural strength and lowest wear; SLA: lowest flexural strengthDid not assess marginal fit accuracy, retention, or surface roughness; SLA printing angle effect on clinical performance needs further study
Arreaza et al., 2026 (PMID: 41233246)Wear influenced by antagonist material type; printed material showed least wear vs. enamelUsed only wear outcome; no fit, hardness, or strength assessment
Šimunović et al., 2025 (PMID: 40710156)Comprehensive review of 3D-printed splints in dentistryReview only; no primary comparative in vitro data generated
Cumulatively, these studies confirm that:
  • The comparison across three fabrication methods is scientifically valid and clinically important
  • Individual outcome parameters have been studied in isolation
  • No single study has simultaneously compared conventional, SLA 3D-printed, and milled splints across a comprehensive battery of in vitro outcomes
Your PhD study therefore occupies a unique position in the literature by providing a standardized, multi-parameter, three-arm in vitro evaluation — making it a high-value original contribution.

7. Summary Statement of Novelty

The novelty of this PhD study lies in its simultaneous, multi-parameter, standardized in vitro comparison of occlusal splints fabricated by three distinct methods — conventional heat-cured PMMA, SLA stereolithography 3D printing, and CAD/CAM subtractive milling. While prior studies have examined individual mechanical or geometric outcomes in isolation, no study has integrated a comprehensive assessment framework encompassing dimensional accuracy, surface hardness, surface roughness, flexural strength, wear resistance, and retention across all three fabrication workflows using a unified in vitro protocol. This study directly addresses the clinical knowledge gap hindering evidence-based selection of fabrication methods for occlusal splints and provides translatable data to guide laboratory and chairside decision-making in an era of rapid digital dentistry adoption.
Key References Supporting This Need Assessment:
  • Assiri KI et al. Retention of 3-D-Printed, Milled, and Conventionally Fabricated Occlusal Splints. Med Sci Monit. 2025. [PMID: 40254853]
  • Aminuddin NL, Petridis H. Flexural Strength, Monomer Release, and Wear of Occlusal Splint Materials. Clin Exp Dent Res. 2026. [PMID: 42035479]
  • Arreaza C et al. Comparison of wear behavior of occlusal device materials. J Prosthet Dent. 2026. [PMID: 41233246]
  • Šimunović L et al. Three-Dimensionally Printed Splints in Dentistry: A Comprehensive Review. Dent J (Basel). 2025. [PMID: 40710156]
  • Chahrour M, Reda B. Assessment of Using Occlusal Splints in TMD Management. Cureus. 2025. [PMID: 40951096]

Write this as starting of my introduction with reference and cite it

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Now I have all the references needed. Here is the fully written, cited introduction for your PhD thesis:

INTRODUCTION

Temporomandibular disorders (TMD) represent a broad spectrum of musculoskeletal and neuromuscular conditions affecting the temporomandibular joint, masticatory musculature, and their associated structures. They constitute one of the most prevalent orofacial pain conditions encountered in dental practice, manifesting clinically as joint and muscle pain, restricted mandibular movement, and joint sounds that collectively impair oral function and quality of life.¹ The global burden of these conditions is further compounded by their frequent co-occurrence with bruxism — a repetitive jaw muscle activity characterized by clenching and grinding of the teeth, occurring during sleep (sleep bruxism) or wakefulness (awake bruxism). A systematic review and meta-analysis by Stanisic et al. (2025) reported a mean prevalence of awake bruxism of 25.9% (95% CI: 22.2–29.9%) in the general population, rising to 50.0% in individuals with TMD.² In a meta-regression analysis synthesizing data from over 37,000 participants across six meta-analyses, Zielinski et al. (2025) demonstrated a global co-occurrence rate of bruxism and TMD of 17%, with the mean prevalence of TMD among bruxism patients reaching 63.5%, underscoring the magnitude of this clinical problem.³
Among the diverse therapeutic strategies available for the management of TMD and bruxism, occlusal splints occupy a central and well-established role. Occlusal splints — also referred to as stabilization splints, Michigan splints, or bite guards — are removable intraoral appliances that overlay the occlusal surfaces of the maxillary or mandibular teeth, designed to redistribute occlusal loads, reduce parafunctional muscular activity, protect tooth surfaces from attrition, and restore a therapeutically stable jaw position.⁴ A Cochrane systematic review by Singh et al. (2024), encompassing 57 randomized controlled trials with 2,846 participants, confirmed that full hard stabilization splints represent the most widely prescribed and evidence-supported form of occlusal intervention for TMD, with particular benefit in reducing muscle pain during function.⁵ A more recent systematic review by Chahrour and Reda (2025) further affirmed the role of occlusal splints as a conservative, non-invasive, and reversible therapeutic modality capable of reducing pain and improving jaw function in TMD patients.⁶
Despite their established clinical utility, the fabrication of occlusal splints has traditionally relied upon a conventional technique involving direct impression-taking, pouring of dental stone casts, and heat-curing or vacuum-forming of polymethylmethacrylate (PMMA) resin over the study model. While this approach has served the profession for decades, it carries inherent limitations that directly affect the quality and performance of the final appliance. Heat-cured PMMA is susceptible to volumetric shrinkage and dimensional distortion during polymerization, resulting in reduced fit accuracy and necessitating extensive chairside adjustments. The manual, laboratory-dependent workflow introduces operator variability, while the material's intrinsic porosity predisposes to surface roughness, bacterial colonization, and residual monomer release — all of which have implications for the appliance's durability, biocompatibility, and patient safety.⁷ A review by Albagieh et al. (2025) highlighted these limitations and recognized the growing imperative to explore digitally driven fabrication alternatives that offer greater reproducibility and precision.⁷
The rapid integration of computer-aided design and computer-aided manufacturing (CAD/CAM) technology into contemporary dental practice has introduced two principal digital fabrication pathways for occlusal splints: subtractive manufacturing (milling) and additive manufacturing (3D printing). CAD/CAM milling involves the computer-guided machining of industrially pre-polymerized PMMA blanks, producing dense, homogeneous appliances with high surface quality and superior mechanical characteristics. Conversely, 3D printing — and specifically stereolithography (SLA), which employs ultraviolet laser photopolymerization of liquid resin to build the appliance in successive layers — offers the potential for complex geometry reproduction, reduced material wastage, and seamless integration into fully digital in-office workflows. Both technologies eliminate the need for physical impressions when integrated with intraoral scanning, reducing clinical steps and patient burden while enabling digital archiving and replication of appliance designs.
The scientific evidence evaluating these fabrication methods has grown substantially in recent years, though significant gaps remain. Orgev et al. (2023) demonstrated that manufacturing technology significantly affects the surface accuracy of occlusal splints, with milled appliances exhibiting superior trueness and precision over both 3D-printed and conventionally heat-polymerized appliances, particularly at the intaglio (tissue-fitting) surface.⁸ Similarly, Cruz-Araujo et al. (2025) investigated the accuracy of LCD-printed occlusal splints fabricated at different printing orientations and found that printing angle significantly influenced precision, with 70-degree vertical orientation yielding the highest precision, and noted that discrepancies were most pronounced in the molar and anterior incisal regions.⁹ Assiri et al. (2025) evaluated the retentive forces of conventionally fabricated, milled, and 3D-printed occlusal splints and reported significantly higher mean retentive forces for conventional splints (16.4 ± 4.94 N) compared to milled (6.42 ± 2.13 N) and 3D-printed splints (4.42 ± 1.53 N), while noting that digitally fabricated splints still achieved clinically adequate retention.¹⁰ A comprehensive in vitro study by Aminuddin and Petridis (2026) comparing flexural strength, monomer release, and wear resistance across conventional, milled, and 3D-printed PMMA found that milled PMMA demonstrated the highest flexural strength (115.5 ± 5.3 MPa), the lowest monomer release, and the least volumetric wear, while 3D-printed resins showed inferior performance across all three parameters — with printing angle significantly influencing flexural strength but not wear.¹¹ Arreaza et al. (2026) further demonstrated in an in vitro oral wear simulation study that wear behavior of occlusal device materials differs significantly across fabrication methods and is additionally influenced by the nature of the opposing antagonist material.¹²
Notwithstanding these contributions, the existing literature remains fragmented. Individual studies have examined discrete outcome parameters — fit accuracy, retention, flexural strength, or wear — in isolation, using varying materials, protocols, and study designs. No standardized, comprehensive, multi-parameter in vitro study has simultaneously compared conventional, SLA 3D-printed, and CAD/CAM milled occlusal splints across a broad battery of clinically relevant outcomes within a unified experimental framework. Furthermore, SLA-specific comparative data within three-arm studies remain sparse relative to DLP and LCD-based printing technologies, and the combined assessment of surface properties (roughness and hardness) alongside dimensional accuracy and mechanical performance in the same investigation has not been undertaken.
It is against this background of growing clinical need, rapid technological evolution, and critical evidence gaps that the present study was conceived. This investigation aims to compare occlusal splints fabricated by the conventional heat-cured PMMA technique, SLA stereolithography 3D printing, and CAD/CAM subtractive milling through a standardized, multi-parameter in vitro protocol — thereby generating a comprehensive and clinically translatable comparative evidence base to guide evidence-informed selection of fabrication methods in contemporary dental practice.

References

  1. Chahrour M, Reda B. Assessment of Using Occlusal Splints Without Other Adjunctive Treatment Modules in the Management of Temporomandibular Disorders: A Systematic Review of Literature. Cureus. 2025. doi:10.7759/cureus.89955 [PMID: 40951096]
  2. Stanisic N, Saracutu OI, Colonna A, et al. Awake Bruxism Prevalence Across Populations: A Systematic Review and Meta-Analysis. J Evid Based Dent Pract. 2025. doi:10.1016/j.jebdp.2025.102171 [PMID: 40716827]
  3. Zielinski G, Pajak-Zielinska B, Pajak A, et al. Global co-occurrence of bruxism and temporomandibular disorders: A meta-regression analysis. Dent Med Probl. 2025;62(2). doi:10.17219/dmp/201376 [PMID: 40099938]
  4. Singh BP, Singh N, Jayaraman S, et al. Occlusal interventions for managing temporomandibular disorders. Cochrane Database Syst Rev. 2024;9:CD012850. doi:10.1002/14651858.CD012850.pub2 [PMID: 39282765]
  5. Singh BP, Singh N, Jayaraman S, et al. (ibid.)
  6. Chahrour M, Reda B. (ibid.) [PMID: 40951096]
  7. Albagieh H, AlWazzan AK, Alhelal FA, et al. Effectiveness of Occlusal Splints in the Management of Temporomandibular Disorders: Comparisons of Treatment Approaches and Digital Versus Conventional Fabrication Techniques. Cureus. 2025;17(1):e77451. doi:10.7759/cureus.77451 [PMID: 39817267]
  8. Orgev A, Levon JA, Chu T-MG, Morton D, Lin W-S. The effects of manufacturing technologies on the surface accuracy of CAD-CAM occlusal splints. J Prosthodont. 2023;32(8):685–693. doi:10.1111/jopr.13610 [PMID: 36227731]
  9. Cruz-Araujo SR, Sampaio-Fernandes MA, de Freitas BN, et al. Accuracy of occlusal splints printed in different orientations by liquid crystal display technology: an in vitro study. J Dent. 2025;152:105461. doi:10.1016/j.jdent.2024.105461 [PMID: 39542078]
  10. Assiri KI, Alqahtani NM, Addas MK, et al. Retention of 3-D-Printed, Milled, and Conventionally Fabricated Occlusal Splints. Med Sci Monit. 2025;31:e947342. doi:10.12659/MSM.947342 [PMID: 40254853]
  11. Aminuddin NL, Petridis H. Flexural Strength, Monomer Release, and Wear of Occlusal Splint Materials Fabricated Through Conventional, Milled, or 3D-Printed Methods. Clin Exp Dent Res. 2026. doi:10.1002/cre2.70361 [PMID: 42035479]
  12. Arreaza C, Seghi RR, Schricker SR, Johnston WM, Saponaro PC. Comparison of wear behavior of occlusal device materials manufactured by different processes. J Prosthet Dent. 2026. doi:10.1016/j.prosdent.2025.10.040 [PMID: 41233246]
Note on citation style: Superscript numbers (¹ ²) in the text correspond to the numbered reference list above. If your institution requires a specific citation format (Vancouver, APA, Harvard, APA 7th), the reference list can be reformatted — just let me know.

Write this as starting of my introduction on Write a note on need assessment of phd study on occlusal splint and why the study was conducted and how it strengthens the novelty of my phd study on comparison of fabrication of occlusal splints fabricated by conventional technique, sla 3d printed and milled , and invitro study , write the reference, in Vancouver style and cite it

I have all the reference data from the previous sessions. Let me write this as a polished PhD thesis introduction with full Vancouver-style citations.

INTRODUCTION

Temporomandibular disorders (TMD) represent a broad and heterogeneous group of musculoskeletal and neuromuscular conditions involving the temporomandibular joint, the masticatory musculature, and their associated structures. These conditions are among the most prevalent orofacial pain disorders encountered in clinical dental practice, presenting with joint and muscle pain, restricted mandibular movement, joint sounds, and functional impairment that collectively compromise oral health-related quality of life.(1) The epidemiological burden of TMD is substantially amplified by its well-documented co-occurrence with bruxism — a repetitive jaw muscle activity characterised by clenching, grinding, or bracing of the teeth, occurring either during sleep (sleep bruxism) or wakefulness (awake bruxism). A systematic review and meta-analysis by Stanisic et al. reported a mean prevalence of awake bruxism of 25.9% (95% CI: 22.2–29.9%) in the general population, escalating to 50.0% (95% CI: 41.1–58.9%) in individuals with concurrent TMD.(2) In a meta-regression analysis synthesising data from over 37,680 participants drawn from six meta-analyses and systematic reviews, Zielinski et al. demonstrated a global co-occurrence rate of bruxism and TMD of 17%, with the mean prevalence of TMD among bruxism patients reaching 63.5%, with marked geographic and sex-based variation.(3) Together, these findings underscore the scale and clinical significance of conditions for which occlusal splint therapy forms the cornerstone of management.
Occlusal splints — variously termed stabilisation splints, Michigan splints, bite guards, or night guards — are removable intraoral appliances that overlay the occlusal surfaces of either the maxillary or mandibular dentition. Their therapeutic rationale encompasses redistribution of occlusal loading forces, reduction of parafunctional masticatory muscle activity, protection of tooth surfaces from progressive attrition, and establishment of a neuromuscularly stable and reproducible jaw position.(4) A Cochrane systematic review by Singh et al., encompassing 57 randomised controlled trials with 2,846 participants, confirmed that the full hard stabilisation splint (FHSS) represents the most extensively studied and evidence-supported occlusal appliance, with particular efficacy in reducing muscle pain during function in patients with myogenous TMD.(5) A complementary systematic review by Chahrour and Reda further affirmed that occlusal splints, by redistributing jaw forces and reducing joint loading and muscular tension, offer meaningful clinical benefits in the reduction of pain, improvement of jaw function, and protection against bruxism-related tooth wear, though their effectiveness as a sole treatment modality warrants further investigation.(6) A narrative review by Albagieh et al. similarly endorsed occlusal splint therapy as a noninvasive, reversible, and effective first-line treatment option for TMD, while recognising the critical role of fabrication quality in determining clinical outcomes.(7)
Despite this well-established clinical utility, the fabrication of occlusal splints has for decades relied upon the conventional technique, wherein dental impressions are recorded, poured in dental stone to produce working casts, and the appliance is subsequently constructed from heat-cured or cold-cured polymethylmethacrylate (PMMA) resin through compression or injection moulding. While this method remains widely practised in dental laboratories globally, it is associated with inherent and well-recognised limitations. Heat-cured PMMA undergoes volumetric contraction during polymerisation, introducing dimensional inaccuracies and distortion that reduce the precision of fit and necessitate extensive chairside adjustment. The manual, multi-step, laboratory-dependent nature of the process introduces operator variability and is time-consuming for both patient and clinician. Furthermore, conventionally processed PMMA exhibits surface porosity and elevated surface roughness that predispose to microbial colonisation, plaque retention, and biofilm formation, while residual monomer release raises ongoing biocompatibility concerns.(7,8) These limitations collectively provide a compelling scientific and clinical rationale for the investigation of alternative fabrication strategies.
The advent and progressive refinement of digital manufacturing technologies in dentistry have introduced two principal alternative pathways for occlusal splint fabrication: subtractive manufacturing (CAD/CAM milling) and additive manufacturing (3D printing). In CAD/CAM milling, a digital design generated from intraoral scanning or digital impressioning is used to direct computer-guided machining of pre-polymerised, industrially fabricated PMMA discs or blocks. The homogeneous polymerisation achieved under controlled industrial conditions endows milled PMMA with superior density, mechanical strength, and surface quality relative to conventionally polymerised material.(8) In contrast, stereolithography (SLA) — a vat photopolymerisation-based 3D printing technology — constructs the appliance incrementally by exposing a liquid photopolymer resin to a focused ultraviolet laser beam, building successive cross-sectional layers to produce the final three-dimensional form. SLA technology is distinguished by its high spatial resolution, capacity to reproduce complex geometry, and suitability for integration into a fully digital workflow from intraoral scan to finished appliance, with potential for in-office fabrication, digital storage, and appliance duplication.(9)
The comparative scientific evaluation of these three fabrication modalities has gained momentum in recent years, though the evidence base remains incomplete and fragmented across individual mechanical and geometric outcome parameters. With respect to dimensional accuracy, Orgev et al. demonstrated that manufacturing technology significantly affects both the trueness and precision of occlusal splints at cameo and intaglio surfaces, with milled appliances achieving the highest trueness and precision, while conventionally heat-polymerised and 3D-printed splints exhibited significantly greater deviations from the reference design, particularly at the critical intaglio surface.(8) Cruz-Araujo et al. reported that printing orientation significantly influenced the precision — though not the trueness — of LCD 3D-printed occlusal splints, with 70-degree vertical orientation yielding the highest precision, and discrepancies concentrated in posterior molar and anterior incisal regions.(9) With respect to retention, Assiri et al. evaluated the retentive forces of conventional, milled, and 3D-printed occlusal splints using a standardised electronic vertical pull device, reporting significantly greater mean retentive forces for conventionally fabricated splints (16.4 ± 4.94 N) compared to milled (6.42 ± 2.13 N) and 3D-printed splints (4.42 ± 1.53 N), while affirming that digitally fabricated splints achieved clinically adequate retention without causing trauma to oral structures.(10) Regarding mechanical properties, Aminuddin and Petridis conducted a systematic in vitro comparison of flexural strength, monomer release, and wear resistance across conventional, milled, and 3D-printed materials, establishing that milled PMMA demonstrated the highest flexural strength (115.5 ± 5.3 MPa), the lowest monomer release (24.9 ± 3.8 ppm), and the lowest volumetric wear loss (2.5 ± 1.3 mm³), while 3D-printed resins exhibited the lowest flexural strength and greatest wear, with printing angle significantly influencing flexural performance.(11) Arreaza et al. further demonstrated that volumetric wear of conventional, milled, and 3D-printed occlusal device materials was significantly influenced by the nature of the opposing antagonist material — human enamel, zirconia, or lithium disilicate — and varied meaningfully across fabrication methods, with 3D-printed material exhibiting the least wear when opposed by the tested antagonists.(12) A comprehensive narrative review by Šimunović et al. synthesised the current state of evidence on 3D-printed splints in dentistry, confirming their growing clinical adoption while identifying the need for further standardised comparative data to support evidence-based practice.(13)
Notwithstanding these valuable contributions, a critical appraisal of the existing literature reveals a fundamental gap: no single standardised, multi-parameter in vitro study has simultaneously evaluated and compared conventional, SLA 3D-printed, and CAD/CAM milled occlusal splints across a comprehensive panel of clinically relevant outcomes — encompassing dimensional accuracy, surface roughness, surface hardness, flexural strength, wear resistance, and retention — within a unified and controlled experimental framework. Existing studies examine discrete properties in isolation, employ divergent materials and methodological protocols, and rarely distinguish SLA from DLP or LCD additive technologies in direct three-arm comparisons. Furthermore, the inter-relationship between fabrication method, material surface characteristics, and mechanical performance has not been holistically characterised. This evidential fragmentation leaves clinicians and laboratory technicians without a comprehensive, comparable dataset upon which to base informed selection of fabrication method for a given clinical scenario.
It is against this background of high clinical prevalence, the documented limitations of conventional fabrication, the rapid expansion of digital dentistry, and the critical gaps in the comparative evidence base that the present PhD study was conceived and designed. This investigation aims to conduct a standardised, multi-parameter in vitro comparison of occlusal splints fabricated by the conventional heat-cured PMMA technique, SLA stereolithography 3D printing, and CAD/CAM subtractive milling — thereby generating a comprehensive, reproducible, and clinically translatable evidence base to inform evidence-based fabrication method selection in contemporary occlusal splint therapy.

REFERENCES

  1. Chahrour M, Reda B. Assessment of using occlusal splints without other adjunctive treatment modules in the management of temporomandibular disorders: a systematic review of literature. Cureus. 2025;17. doi:10.7759/cureus.89955
  2. Stanisic N, Saracutu OI, Colonna A, Wu W, Manfredini D, Häggman-Henrikson B. Awake bruxism prevalence across populations: a systematic review and meta-analysis. J Evid Based Dent Pract. 2025. doi:10.1016/j.jebdp.2025.102171
  3. Zielinski G, Pajak-Zielinska B, Pajak A, Wojcicki M, Litko-Rola M, Ginszt M. Global co-occurrence of bruxism and temporomandibular disorders: a meta-regression analysis. Dent Med Probl. 2025;62(2). doi:10.17219/dmp/201376
  4. Romero-Reyes M, Bassiur JP. Temporomandibular disorders, bruxism and headaches. Neurol Clin. 2024;42(2):557–73. doi:10.1016/j.ncl.2023.12.008
  5. Singh BP, Singh N, Jayaraman S, Kirubakaran R, Joseph S, Muthu MS. Occlusal interventions for managing temporomandibular disorders. Cochrane Database Syst Rev. 2024;9:CD012850. doi:10.1002/14651858.CD012850.pub2
  6. Chahrour M, Reda B. Assessment of using occlusal splints without other adjunctive treatment modules in the management of temporomandibular disorders: a systematic review of literature. Cureus. 2025;17. doi:10.7759/cureus.89955
  7. Albagieh H, AlWazzan AK, Alhelal FA, Alem MF, Albaiz AM, Aloraini TK. Effectiveness of occlusal splints in the management of temporomandibular disorders: comparisons of treatment approaches and digital versus conventional fabrication techniques. Cureus. 2025;17(1):e77451. doi:10.7759/cureus.77451
  8. Orgev A, Levon JA, Chu T-MG, Morton D, Lin W-S. The effects of manufacturing technologies on the surface accuracy of CAD-CAM occlusal splints. J Prosthodont. 2023;32(8):685–93. doi:10.1111/jopr.13610
  9. Cruz-Araujo SR, Sampaio-Fernandes MA, de Freitas BN, Simionato AA, Figueiral MH, Macedo AP. Accuracy of occlusal splints printed in different orientations by liquid crystal display technology: an in vitro study. J Dent. 2025;152:105461. doi:10.1016/j.jdent.2024.105461
  10. Assiri KI, Alqahtani NM, Addas MK, Zarbah M, Alqahtani AM, Alamri FAA. Retention of 3-D-printed, milled, and conventionally fabricated occlusal splints. Med Sci Monit. 2025;31:e947342. doi:10.12659/MSM.947342
  11. Aminuddin NL, Petridis H. Flexural strength, monomer release, and wear of occlusal splint materials fabricated through conventional, milled, or 3D-printed methods. Clin Exp Dent Res. 2026. doi:10.1002/cre2.70361
  12. Arreaza C, Seghi RR, Schricker SR, Johnston WM, Saponaro PC. Comparison of wear behavior of occlusal device materials manufactured by different processes. J Prosthet Dent. 2026. doi:10.1016/j.prosdent.2025.10.040
  13. Šimunović L, Čimić S, Meštrović S. Three-dimensionally printed splints in dentistry: a comprehensive review. Dent J (Basel). 2025;13(7). doi:10.3390/dj13070xxx
Format note: All references are in Vancouver style — numbered sequentially in order of first appearance, with superscript numbers in the text corresponding to the reference list. Author surnames are followed by initials, journal titles are abbreviated per NLM standards, and DOIs are included throughout. Reference 13 DOI page suffix should be confirmed from the published article. If you need this formatted as a Word document (.docx) for submission, let me know.
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