A Newly Proposed Method to Predict Optimum Occlusal Vertical Dimension

Comparing analog and 3D measurements of vertical dimension in edentulous subjects

OBJECTIVE

This study aimed to explore the feasibility and reliability of measuring the vertical dimension of occlusion/rest (OVD/RVD) on 3D facial scans of edentulous patients.

METHODS

Nineteen edentulous participants rehabilitated with complete removable dental prostheses (CDs) participated in this study. Analog measurements (control) were obtained directly on the face for each participant with the jaws positioned at the rest position (without CDs, RVD) and at centric occlusion (with dentures, OVD), between the facial landmarks: Glabella (G) and Soft Pogonion (SP), Pronasale (PN) and SP, and Subnasale (SN) and SP. Participants' faces were scanned twice, using a face-scanner (Class 1 LASER, Obiscanner). Scans were imported into a mesh-processing software, and the OVD/RVD were measured digitally. Two investigators performed all the measurements and were blinded. Data analysis included intra-class correlation coefficient (ICC) and pairwise comparison tests (p < 0.05).

RESULTS

Digital measurements were higher than analog measurements, and the mean paired difference ranged from -4.86±3.2 to 0.42±2.7 mm. All the differences were statistically significant, expect for SN-SP (p = 0.110). Magnitude of the differences for the RVD were large for G-SP and SN-SP (ES>0.80) and moderate for PN-SP (ES>0.50). There was a large effect for G-SP when measuring OVD (ES>0.50), and small effect for PN-SP and SN-SP (ES≤0.20).

CONCLUSION

Considering the limitations associated with the specific type of facial scanner used in this study, it can be concluded that registering the resting vertical dimension in edentulous patients through digital methods may not be currently recommended. This is due to the potential errors that may arise during the data acquisition process, which could compromise the accuracy and reliability of the measurements.

CLINICAL SIGNIFICANCE

Digital methods for registering the vertical dimension of rest (RVD) in edentulous patients can introduce errors, resulting in occlusal errors and discomfort. Clinicians must, for the moment, still use conventional analog methods to ensure accurate RVD measurement for a successful denture therapy.

Myths surrounding vertical dimension of occlusion in restorative dentistry: A scoping review

OBJECTIVE

This scoping review aims to clarify the concept of vertical dimension of occlusion (VDO) in prosthetic dentistry, addressing prevalent myths, and controversies regarding its clinical management and impact on the stomatognathic system.

METHODS

This paper critically examines common beliefs about VDO alteration and its effects on temporomandibular disorders (TMD) through an extensive literature review and an international survey. The survey included 862 general dentists and prosthodontists and explored their approaches to altering VDO and their perceptions of the clinical implications. The literature review provided a thorough analysis of existing research on VDO modification techniques, the adaptability of the stomatognathic system, and the relationship between VDO changes and TMD.

RESULTS

The survey revealed insights into dentists' perspectives on VDO, showing that while many practitioners test a new VDO due to concerns about patient adaptation, a significant majority observed that patients typically adjust well to a new VDO regardless of the technique used. The survey highlighted differing beliefs about the need for a gradual process and trial phase for VDO alteration, as well as the stability of modified VDO. Literature review suggests the stability and adaptability of VDO changes due to muscle adaptability and indicates no direct causal or curative link between VDO changes and TMD. Traditional methods for determining VDO in complete dentures may not be suitable for worn dentition, underscoring the need for tailored approaches.

CONCLUSION

This paper suggests that the traditional belief in the need for a prolonged trial phase for VDO alterations may be reconsidered in light of evidence supporting the adaptability of the stomatognathic system. Moreover, it emphasizes the importance of distinguishing between methods suitable for complete dentures and those for managing cases of worn dentition. The purported link between VDO alterations and TMD is also found to lack scientific evidence, highlighting the need for individualized patient care based on current evidence and clinical judgment.

The "Smile Design and Space" Concept for Altering Vertical Dimension of Occlusion and Esthetic Restorative Material Selection

OBJECTIVE

This article introduces the smile design and space (SDS) concept for managing the vertical dimension of occlusion (VDO) in full-mouth reconstructions and its influence on the selection of esthetic restorative materials. Limitations of traditional VDO adjustment methods are being addressed through a facially driven treatment approach that enhances esthetics improves function and minimizes invasiveness.

CLINICAL CONSIDERATIONS

The SDS concept involves detailed evaluations of the incisal edges of the maxillary central incisors in relation to the upper lip at rest and at full smile. This includes analyzing variations in incisal exposure due to differing lip mobility, which can significantly impact gingival esthetics, particularly in cases with gingival exposure during smiling. The concept employs a strategic formula to determine the necessary alterations in VDO based on specific dental relationships and wear patterns.

CONCLUSIONS

The SDS concept provides guidelines for full-mouth reconstructions, emphasizing minimal invasiveness and the integration of esthetics with functional dynamics to enhance the predictability of clinical outcomes and reduce complications associated with traditional restoration techniques.

CLINICAL SIGNIFICANCE

The SDS concept enhances the precision of full-mouth reconstructions through individualized adjustment of the VDO, tailored to the esthetic and functional requirements of each patient.

Increasing Vertical Dimension of Occlusion (VDO): Review

The need to increase the Vertical Dimension of Occlusion (VDO) to restore lost dental function or optimise specific dental treatments is a common occurrence in daily dental practice. The common belief that the Vertical Dimension at Rest (VDR) is fixed hinders the development of restorations with a VDO that encroaches on or surpasses the interocclusal rest space (IRS), thereby preventing potential tissue damage to the masticatory apparatus. Recent studies have shown that the mandible rest position falls within a range termed as the "comfort zone". The range of this zone may vary from one person to another and within the same person over time due to factors such as age or health status. In this review, we have concluded that a permanent increase in the VDO, once indicated, is a safe procedure for dentulous patients. However, it is important to minimise the extent of the increase to simplify the prosthodontics treatment process. An inter-incisal increase exceeding 5 mm is seldom needed. Moreover, it is important to consider the functional, aesthetic, and biological elements associated with VDO. The biological and functional environment closely related to the VDO had great adaptive capacities, which have for a historically been underestimated. Patient adaptation has been observed in dentate patients, edentulous patients, and even cases involving implant-supported prostheses. Muscle relaxation and changes in muscle length are likely the primary adaptation mechanisms, rather than the restoration of the original VDO through dentoalveolar maturation. Intervention with a fixed restoration is more predictable and results in a higher and more rapid level of adaptation. Finally, the increase should include the entire arch to prevent relapse of the VDO to its previous value, and changes in VDO should be assessed by utilising temporary diagnostic restorations for a period before implementing definitive prostheses, in order to evaluate the adaptive muscle response.

Effects of conventional complete dentures and implant-supported overdentures on alveolar ridge height and mandibular bone structure: 2-year and 6-year follow-up study

OBJECTIVES

The aim of this study was to compare the changes in mandibular bone structure in edentulous patients who were rehabilitated with conventional complete dentures (CCD) and implant supported overdentures (ISO), by evaluating alveolar bone loss (ABL), panoramic mandibular index (PMI), mandibular cortical width (MCW), gonion index (GI), antegonial index (AI), and articular eminence inclination (AEI).

MATERIALS AND METHODS

Panoramic radiographs of 63 edentulous patients using CCD, 63 edentulous patients using ISO, and 126 patients without tooth loss were evaluated. Edentulous patients had a 2-year and 6-year follow-up panoramic radiograph image. ABL (anterior, premolar, and molar regions), MCW, PMI, AI, GI, and AEI were measured in each patient. Variation between measurements was analyzed using repeated measures ANOVA test and post hoc Tukey test.

RESULTS

Both edentulous groups showed significantly lower mean than without tooth lost group in all measures (p < 0.000). ISO group showed significantly lower mean ABL than CCD group in anterior (p = 0.000), right premolar (p = 0.005), left premolar (p = 0.005), right molar (p < 0.000), and left premolar (p < 0.000) regions in short term. ISO group showed significantly lower mean ABL than CCD group in anterior (p = 0.021), right molar (p < 0.000), and left premolar (p < 0.000) regions in long-term. There is no statistically significant difference between the CCD and ISO groups in right premolar (p = 0.200) and left premolar (p = 0.134) regions in long term. Both edentulous groups showed significantly lower mean MCW (p < 0.000), PMI (p < 0.000), AI (p < 0.000), GI (p < 0.012), and AEI (p < 0.002) than the without tooth loss group. There is no statistically significant difference between the CCD and ISO groups in terms of changes in the mean MCW, PMI, AI, GI, and AEI measurement in short and long term (p > 0.000).

CONCLUSIONS

In the short and long term, edentulism reduced alveolar crest height, MCW, and AEI in individuals, but had no effect on PMI, AI, or GI. The use of prosthesis did not prevent the decrease of alveolar crest height, MCW, or AEI (CCP or ISO). In the short and long term, however, ISO created less ABL in the mandibular anterior and molar regions than CCD.

CLINICAL RELEVANCE

ABL cannot be halted in edentulous people, but by using ISO instead of CCD for rehabilitation, resorption can be reduced.

Comparison of patient satisfaction between complete dentures fabricated using "conventional" and "cephalometric angular reconstruction" vertical dimension procedures: A multicenter randomized clinical trial

Aim

In Prosthodontics, during complete denture fabrication, conventional methods employed to determine occlusal vertical dimension require patient co-operation. Hence, the aim of the present study is to evaluate the clinical effectiveness of the 'cephalometric angular reconstruction' procedure in the calculation of these lost dimensions.

Settings and Design

Multicentric randomised clinical trial conducted in four dental hospitals.

Materials and Methods

Fully edentulous people who came to the hospitals for complete denture treatment were recruited into the study. Those who fulfilled the inclusion criteria were randomly assigned to two groups; Group 1: Dentures fabricated using a 'conventional' procedure and Group 2: Dentures fabricated using 'cephalometric angular reconstruction'. The patient's level of satisfaction was assessed on a scale of 1 to 5; 1-dissatisfaction to 5-excellent. The confounding factors that can influence the satisfaction were also recorded.

Statistical Analysis Used

The distribution of patient's satisfaction was assessed using Chi-square test, whereas the difference between the two groups was evaluated using Mann-Whitney test.

Results

There was no significant difference either in the vertical dimension determined (P = 0.465) or the patient's level of satisfaction (P = 0.943) between the two groups. There was no influence of confounding factors considered in the present study on the satisfaction levels. There was no difference in the distribution of satisfaction levels based on the dentist's quality assessment (P = 0.243).

Conclusion

Complete dentures fabricated using cephalometric angular reconstruction procedure of vertical dimension determination were equivalent with respect to patient satisfaction, compared to those made using a conventional method. Hence, the new method can be clinically recommended during denture fabrication.

Predictive Model for Occlusal Vertical Dimension Determination and Digital Preservation with Three-Dimensional Facial Scanning

(1) Background: Occlusal vertical dimension (OVD) in the optimal maxillo–mandibular relationship is an important parameter to establish when complex dental rehabilitation has to be done. The optimal method to measure OVD is still a challenge in everyday practice. The aim of the present study was to test the reliability of the correlation between OVD and some anthropometric and cephalometric methods described in the literature. The validity of OVD registration using a facial scanner was also assessed. (2) Materials and Methods: 150 dentate participants, aged 20–25 years, were randomly selected using sealed envelopes. Anthropometric measurements between specific standard points were performed: Subnasion–Prementon (Sn–PM) and Subnasion–Gnation (Sn–Gn) in maximum intercuspation and in the rest mandibular position, right and left pupil to the corresponding chelion. The cephalometric measurements registered were the lower facial angle and the angle between mandibular and Frankfurt planes. The distance Sn–Gn in maximum intercuspation was compared to all other parameters. Facial scanning, with a mobile phone and installed dedicated application, was performed on ten subjects, randomly selected using the same method among the participants, and the obtained 3D files were analyzed. The digital measurements were compared, for validity, to the clinical measurements. Pearson’s correlation coefficient was used, for comparing clinical Sn–Gn in maximum intercuspation position to the other parameters. (3) Results: A strong agreement between all measured anthropometric parameters of the facial scan and clinical contact measurement method was registered. None of the measured parameters could predict the exact OVD. (4) Conclusions: In the limits of our study, the facial scanning could be used for predictable registration of OVD and the stored digital information could be preserved through life and use for oral rehabilitation. However, if OVD needs to be determined, several measurement methods, including cephalometric measurements, need to be used simultaneously to reach a final decision.

An Anthropometric Study of Cranio-Facial Measurements and Their Correlation with Vertical Dimension of Occlusion among Saudi Arabian Subpopulations

BACKGROUND

Determining and restoring physiological vertical dimension of occlusion (VDO) is the critical step during complete mouth rehabilitation. The improper VDO compromises the aesthetics, phonetics and functional efficiency of the prosthesis. Various methods are suggested to determine the accurate VDO, including the facial measurements in the clinical situations with no pre-extraction records. The generalisation of correlation between the facial measurements to VDO is criticised due to gender dimorphism and racial differences. Hence, it is prudent to verify the hypothesis of facial proportion and correlation of lower third of the face to remaining craniofacial measurements in different ethnic groups. The objective of the study was to evaluate the correlation of craniofacial measurements and OVD in the Saudi-Arabian ethnic group.

METHODOLOGY

Total of 228 participants from Saudi-Arabian Ethnic group were randomly recruited in this cross-sectional study. Fifteen craniofacial measurements were recorded with modified digital Vernier callipers, and OVD was recorded at centric occlusion. The obtained data were analysed by using the Spearman's correlation and linear regression analysis.

RESULTS

The Mean OVD in male participants was higher (69.25 ± 5.54) in comparison to female participants (57.41 ± 5.32). The craniofacial measurement of Exocanthion-right labial commissure and the Mesial wall of the right external auditory canal-orbitale lateral had a strong positive correlation with VDO. The strong correlation was recorded with a trichion-upper border of right eyebrow line and trichion-Nasion only in males. Meanwhile, the length of an auricle recorded the positive correlation in female participants.

CONCLUSIONS

Being simple and non-invasive technique, craniofacial measurements and linear equations could be routinely utilised to determine VDO.

Determination of the occlusal vertical dimension in edentulous patients using lateral cephalograms

The determination of the occlusal vertical dimension (OVD) in edentulous patients is based on clinical assessment with high variability. This study tested the hypothesis: The average OVD in edentulous patients with conventional dentures is too low compared to orthodontic norms, when only clinical parameters are used for the determination of the OVD. Edentulous patients with conventional full dentures were enrolled. Clinical parameters were judged by two senior prosthodontists. Digital lateral cephalograms were taken and served to calculate the OVD according to the lower face height angle (ANS-Xi-D) taking tooth-independent facial growth patterns into account. The ANS-Xi-D angle was compared with reference values by applying one-sample mean comparison tests. Thirty-six participants (17 female, 19 male; mean age 65.3 ± 10.6 years) were enrolled in this study. Clinically, the OVD of four dentures was judged too low, in one case too high, and in the other 31 cases as correct. The mean ANS-Xi-D angle was 48.28°±4.86 and statistically not different to the norm value of 49°±4 (n.s.). There was a tendency that the ANS-Xi-D angle was different between participants with different tooth-independent facial growth patterns (ANOVA, P = .0548). Predominantly, clinically sufficient prostheses show adequate ANS-Xi-D angles. Short-face type denture patients are often restored to comply with mesiofacial norms. The determination of the OVD based on lateral cephalography is not recommendable to be a standard diagnostic parameter. Orthodontic norms are derived from dentate cohorts and might not take the continuing facial growth and other confounding factors of edentulous subjects into account.

Correlation between Finger Length and Occlusal Vertical Dimension in Adult Sudanese Women

The objective of this study was to investigate the correlation between the length of each of three fingers (the index finger, 2D; ring finger, 4D; and little finger, 5D) and the occlusal vertical dimension (OVD). If such a relationship were established, it would simplify and facilitate the prediction and reestablishment of the OVD in the construction of complete dentures. The correlation between the OVD and the length of 2D or 5D has already been investigated in a number of studies. However, to our knowledge, no study has investigated the relationship between the length of 4D and the OVD. A total of 117 adult Sudanese women were enrolled in this study. The distance from tip of the finger to the second crease was measured using a digital caliper. The OVD was established based on two measurements: one from the septum of the nose to the menton of the chin; and the other from the tip of the nose (N) to the gnathion at the tip of the chin (Gn). All data were analyzed using the SPSS program. The Pearson correlation coefficient was used to determine the relationship between variables. Differences between means were determined using a paired-sample t-test. The p-value was set at 0.05. A significant correlation was found between finger length and the OVD. However, this correlation was significantly higher between 2D and the OVD based on N-Gn. The present findings indicate that 2D can be used to predict the OVD in adult Sudanese women.

Determination of occlusal vertical dimension for complete dentures patients: an updated review

Determination of the occlusal vertical dimension (OVD) is an integral part of complete dentures fabrication. Due to the lack of teeth, the clinician faces the challenge of how to accurately establish the OVD of the new denture. Therefore, the purpose of this review article was to present, discuss and critique the available methods used in determining the OVD for complete dentures patients. This review identified two main streams to determine the OVD: (i) pre-extraction methods and (ii) post-extraction methods. For the pre-extraction methods, the OVD of the natural dentition is transferred to the new dentures mainly by intra-oral measurements, profile tracing and cephalometric analysis. The post-extraction methods rely on mandibular rest position, facial aesthetic appearance, swallowing pattern, craniofacial landmarks measurements, cephalometric analysis, phonetics and existing dentures. In general, all the available techniques have merits and are helpful for routine clinical use. However, they are empirical in nature, controversial and lack the scientific support. Further, there is no single accurate method for OVD determination. To overcome the limitations of the techniques, the clinician will benefit from applying combination of techniques to approximate the OVD.

Determination of vertical dimension of occlusion using lateral profile photographs: A pilot study

Purpose:

To hypothesize a new theory based on soft tissue reference points on lateral profile photographs (LPPs) for determining the vertical dimension of occlusion (VDO), as there is need to explore for simple strategies.

Materials and Methods:

Fifty-three participants in the age range of 20–27 years who met the inclusion criteria were recruited. LPPs were taken for all participants using standard protocol and duplicate copies obtained, on which five soft tissue reference points, nasion (Stn), subnasale (Stsn), porion (Stp), gnathion (Stgn), and gonion (Stg) (Stg prenoted on the face) were marked and joined to form angles; distance between Stsn and Stgn was considered as VDO in LPP (VDO-LP). The angle formed between Stn-Stsn-Stgn and Stn-Stsn-Stg; Stp-Stg-Stgn and Stp-Stg-Stsn was correlated; two simple linear regression models were developed to predict Stn-Stsn-Stgn and Stp-Stg-Stgn using Stn-Stsn-Stg and Stp-Stg-Stsn as independent variables. Using the formulae, VDO-LP predicted was constructed and correlated with the actual values.

Results:

The angle Stn-Stsn-Stgn had a statistically significant moderate positive correlation with Stn-Stsn-Stg (r = 0.57, P < 0.001) and angle Stp-Stg-Stgn, a significant strong positive correlation with Stp-Stg-Stsn (r = 0.81, P < 0.001). Using simple linear regression analysis, the following formulae were obtained: Stn-Stsn-Stgn (in degrees) = 0.776 Stn-Stsn-Stg (in degrees) +79.01 and Stp-Stg-Stgn (in degrees) =1.331 Stp-Stg-Stsn (in degrees) +10.2. The predicted and actual VDO-LP values were in strong positive correlation with a coefficient of 0.8.

Conclusion:

With the use of simple landmarks on LPP, it is possible to reconstruct the lost facial dimensions during prosthetic replacement of lost teeth.

Hereditary gingival fibromatosis with extreme ridge thickness and insufficient interarch distance: A clinical report of surgical and prosthetic management

Hereditary gingival fibromatosis is a rare genetic disorder resulting in gingival overgrowth that can be found in both dental arches. As a result of the gingival overgrowth and associated dental displacement, affected patients occasionally present with increased occlusal vertical dimension and/or inadequate lip closure. Depending on the disorder's severity, these patients can be challenging to treat. This clinical report describes a comprehensive surgical and prosthetic approach to the rehabilitation of a middle-aged patient with severe manifestations of hereditary gingival fibromatosis and severe generalized chronic periodontitis.

Reestablishment of Occlusal Vertical Dimension in Complete Denture Wearing in Two Stages

The assessment and reestablishment of the occlusal vertical dimension (OVD) are considered important factors in the treatment of complete denture wearers. The long-time use of a complete denture can result in jaw displacement due to abrasion of the artificial teeth and residual ridge resorption, causing esthetic complications. Most patients with old dentures and incorrect OVD accept reestablishment of the OVD with new complete dentures, even if they were used to their old dentures. The present clinical report describes a method of gradual reestablishment of OVD using a diagnostic acrylic splint on artificial teeth in old complete dentures before the manufacture of new complete dentures.Clinical Significance. The use of a reversible treatment for reestablishment of the OVD in old complete dentures with a diagnostic occlusal acrylic splint allows for the reestablishment of the intermaxillary relationship, providing physiological conditions of masticatory performance associated with the recovery of facial esthetics in edentulous patients.