A Systematic Method for a Full-Mouth Rehabilitation of a Dentition With Extensive Overjet and Occlusal Dysfunction.

A patient presented desiring to improve her esthetics and reduce masseter muscle pain prior to her upcoming wedding. Although the patient had a full-mouth rehabilitation with porcelain restorations at age 16, she presented with extensive overjet, unbalanced occlusion, and lack of contact from premolar to premolar. The clinician was faced with the challenge of determining the best course of treatment. After completing thorough record-taking and a detailed analysis following a systematic approach, the clinician developed a facially driven treatment plan that was carried out over eight phases. The patient's existing crowns were replaced at a reduced vertical dimension of occlusion, esthetics were enhanced, muscle pain was relieved, and her goals were achieved.

Full-mouth rehabilitation with lithium disilicate ceramic crowns in hypoplastic amelogenesis imperfecta: a case report and review of literature.

BACKGROUND: Amelogenesis imperfecta (AI) is a group of genetic disorders characterized by tooth discoloration and enamel defects. Patients with AI always exhibit generalized attrition and defective tooth structure, leading to the loss of occlusal vertical dimension (OVD). Appropriate rehabilitation is challenging and essential to improve patients' aesthetics and function. CASE PRESENTATION: This case report presents a comprehensive management of a 30-year-old woman with hypoplastic AI. A 52-month follow-up revealed satisfactory full-mouth rehabilitation performances of lithium disilicate ceramic crowns after clinical crown lengthening, with increased vertical dimension. CONCLUSIONS: Patients with severe hypoplastic AI require proper full-mouth rehabilitation. Using full-crown lithium disilicate restorations to increase the OVD by 2‒4 mm is a safe and predictable recommendation for such cases. In addition, patients with AI require complex and comprehensive management. The long-term effects of full-mouth rehabilitation with lithium disilicate ceramic crowns still necessitate further follow-ups.

Assessment of the Vertical Dimension of Occlusion Using Palm Width and Finger Length.

Background and Objectives: The vertical dimension of occlusion's (VDO) assessment is a highly important issue in the everyday dentist's practice. Patients with unstable occlusion, lost occlusal stops, extensive tooth loss in the lateral area, or complete edentulism need a proper assessment of the VDO before the prosthetic restoration is carried out. Subjective and objective methods were used over time for the restoration of VDO. The study aimed to investigate the possible correlation between finger length, palm width and the vertical dimension of occlusion. Materials and Methods: Assessment of the VDO for 236 subjects, Romanian and French dental students, was performed using the Willis Bite Gauge. The left hand of the subjects was scanned using a flat-bed scanner, and then measurements of palm width and finger length were carried out for each subject. Comparison between VDO values and finger length/palm width was conducted using one-way ANOVA and Student t-Test. Results: Higher VDO average values were found in French subjects compared with Romanian students. The same results were found according to gender; in both female and male subjects, lower values of VDO were found in the Romanian group. Higher values were obtained for women within each group when comparing to men. Statistically significant correlations of the analyzed parameters and VDO values were found. Higher statistical correlations of the studied variables were found for men compared to women in both groups. The highest statistical correlation was obtained between the VDO and the palm width measured at the fingerbase, followed by the middle finger length. Conclusions: The results showed the highest statistical correlation between the vertical dimension of occlusion and the palm width measured at the fingers' base. Statistical correlations were also found between the VDO and the middle finger length. Simple formulas using finger length/palm width can be used for a rapid VDO determination.

Vertical and transverse treatment effects of Invisalign First system compared to Hyrax maxillary expanders with fixed appliances in mixed dentition patients.

OBJECTIVES: To compare vertical and transverse changes in mixed dentition patients treated with the Invisalign First System (IFS) to those treated with a banded hyrax expander with fixed appliances (Hyrax) and control groups, and to assess the efficiency rate of dental arch expansion with IFS. MATERIALS AND METHODS: The study included 80 mixed dentition patients, with 40 in each group (IFS and Hyrax) and 40 controls from the American Association of Orthodontists Foundation Craniofacial Growth Legacy Collection. Skeletal and dental vertical dimension changes and arch width changes between pretreatment (T1) and posttreatment (T2) were evaluated. RESULTS: Age at T1, time interval (T1-T2), sex, and Angle class did not significantly differ among the groups. Mandibular plane angle changes showed a similar reduction for the control and IFS groups, with no changes in the Hyrax group. However, the differences among the three groups did not reach statistical significance (P = .06). The Hyrax group showed significantly greater expansion in maxillary intermolar width compared to the IFS group, 4.4 vs 2.5 mm, respectively. The efficiency of maxillary expansion using IFS ranged from 52.3% to 76.87%. CONCLUSIONS: During the mixed dentition stage, no significant changes occurred in vertical dimensions among the control, Hyrax, and IFS groups. Although there was a trend suggesting a greater reduction in mandibular plane angle in the IFS group compared to the Hyrax group, this may not be clinically significant given the less than 1° difference. IFS can be a viable option for addressing mild arch width deficiencies, with a predictable increase in intermolar width of approximately 2.5 mm.

Mandibular response after rapid maxillary expansion in mixed dentition children with different vertical growth patterns: a retrospective study.

This study evaluated the mandibular development induced by rapid maxillary expansion (RME) therapy in mixed dentition patients with different vertical growth patterns through long-term observation. The research utilized a retrospective design that included two cohorts: a control group consisting of pediatric subjects with individualized malocclusions, and an experimental group received RME therapy. A total of 60 subjects were included; 37 in the RME group (17 males and 20 females) and 23 in the control group (13 males and 10 females). Based on mandibular plane angles, 19 pertinent cephalometric variables were quantified with Dolphin Imaging software, and participants were subclassified into high-angle and normal-angle subgroups. Changes in the groups during the observation period were statistically analyzed with a t-test. Compared to the control group, both sagittal parameters tended to decrease after treatment in the RME group (p < 0.05), and none of the vertical correlations were statistically different (p > 0.05). Within the normal-angle experimental subgroup, sagittal parameters markedly decreased when contrasted with their normal-angle control group (p < 0.05). Notably, a substantive decrease in overjet was solely observable in the sagittal dimension among the high-angle expansion subgroup when compared to the high-angle control subgroup (p < 0.05). In the vertical dimension, neither the normal-angle nor high-angle subgroups exhibited any statistically significant differences from their respective control cohorts (p > 0.05). Based on long-term observation, RME therapy promotes mandible sagittal growth of the mandible in subjects with normal-angle vertical growth patterns. A similar tendency was not observed in subjects with high-angle vertical growth patterns. In addition, the mandibular plane angle did not increase after RME in children with high-angles.

Quality of occlusal outcome in adult Class II patients treated with completely customized lingual appliances and Class II elastics compared to adult Class I patients.

OBJECTIVES: The aim of this investigation was to evaluate whether Class II malocclusion in adult patients can be successfully corrected using a completely customized lingual appliance (CCLA) in combination with Class II elastics. METHODS: In order to detect differences in the final treatment outcome, two groups were matched for age and gender. Treatment results of 40 adult orthodontic patients with a Class I malocclusion (Group 1) were compared to 40 adults with a Class II malocclusion (Group 2). All patients had completed treatment with a CCLA (WIN, DW Lingual Systems, Bad Essen, Germany) without known centric occlusion-centric relation discrepancies, issues of compliance, or overcorrection in the individual treatment plan which was defined by a target set-up. In order to compare the treatment results of the two groups, 7 measurements using the American Board of Orthodontics Model Grading System (ABO MGS) and linear measurements for anterior-posterior (AP) and vertical dimensions were assessed at the start of lingual treatment (T1), after debonding (T2B) and compared to the individual target set-up (T2A). RESULTS: A statistically significant AP correction was achieved in Group 2 which represented 95% of the planned amount. The planned overbite correction was fully achieved in the Class I and Class II group. In both groups, there was a statistically significant improvement in the ABO scores, with no significant difference between the two groups at T2. 100% of the patients in Group 2 and 92.5% in Group 1 would meet the ABO standards after CCLA treatment. LIMITATIONS: The main limitation of this study is that only patients who were wearing the elastics as prescribed were retrospectively included. Therefore, the results of this study may have limited generalizability. CONCLUSIONS: Completely customized lingual appliances in combination with Class II elastics can correct a Class II malocclusion successfully in adult patients. The final treatment outcome can be of a similar high quality in Class I and Class II patients.

Evaluation of various anthropometric measurements for the determination of the occlusal vertical dimension.

STATEMENT OF PROBLEM: Studies on anthropometric measurements, one of the methods used in determining the occlusal vertical dimension, have been limited to the evaluation of only a few facial and hand parameters. PURPOSE: The purpose of this clinical study was to determine the possible relationships between all facial and hand measurements reported in the literature and assumed to be correlated with the occlusal vertical dimension and reveal their proportional relationships. MATERIAL AND METHODS: The study included a total of 271 participants, 136 women (30.37 ±8.09 years) and 135 men (30.42 ±8.49 years). A total of 36 measurements, including 4 occlusal vertical dimensions and 24 facial and 8 hand measurements, were obtained for each participant. Measurements were obtained directly from the soft tissue landmarks of the participants using 4 digital vernier calipers (Accud Digital Caliper; Accud), each designed for a different purpose. The normality of the parameters was analyzed using the Kolmogorov-Smirnov and Shapiro-Wilk tests, and the relationships between the parameters were analyzed using the Pearson correlation analysis (α=.05). Simple and multivariate linear regression analyses were also performed. Correlation coefficients were categorized as strong (r≥0.6), moderate (0.6>r>0.3), and weak (r≤0.3). Moreover, regression formulas were established for strongly correlated parameters. RESULTS: Facial and hand measurements that showed strong correlations with occlusal vertical dimension measurements were the distance between the pupil of the eyes, the pupil of the eye-to-cheilion, sellion-to-stomion, sellion-to-labiale inferius, stomion-to-pogonion, meatus-to-exocanthion, and exocanthion-to-cheilion distances and the 4-finger width measurement between the index and little fingers. CONCLUSIONS: Certain anthropometric facial and hand measurements and regression formulas derived from the parameters that revealed strong correlations can be used to determine the occlusal vertical dimension.

A novel formula for estimating the vertical dimension of occlusion using panoramic radiography.

BACKGROUND: This study aimed to develop a new formula to easily estimate the vertical dimension of occlusion (VDO) by using the distance between the mental foramen on a panoramic radiograph. SUBJECTS AND METHODS: A total of 508 dentulous subjects were selected from outpatient dental clinics at the College of Dental Medicine, Al-Azhar University. The vertical dimension of the occlusion was measured using a single calibrated calliper. For each subject, a digital panoramic radiograph was taken with fixed exposure parameters. The intermental foramina distance (IMFD) was measured. The data were collected and then analysed using the IBM SPSS version 20.0 software package. (Armonk, NY: IBM Corp.). Linear regression was used to determine the relationship between the intermental foramina distance (IMFD) and the vertical dimension at occlusion (VDO). RESULTS: Pearson's correlation analysis revealed that there was a strong correlation between the intermental foramina distance (IMFD) and the VDO. Thus, a novel formula was developed for determining the VDO using panoramic radiography. CONCLUSION: The novel formula developed herein facilitated the determination of the VDO among prosthetic rehabilitation for subjects who lost vertical dimension due to loss of posterior teeth or severe wear of natural posterior teeth. Further studies are needed to determine the clinical applicability of the derived formulae for edentulous subjects.

Relationship of buccolingual inclination between the alveolar bone and first molar in different vertical facial types: A CBCT study.

BACKGROUND: This study aimed to investigate the differences in the buccolingual inclination and transverse width of maxillary and mandibular first molars among different vertical facial types. METHODS: In all, 78 samples were divided into three groups based on the GoGn-SN angle: the low-angle group (n = 26, mean age=24.21±5.11), average-angle group (n = 26, mean age=22.66±3.72), and high-angle group (n = 26, mean age=22.23±2.43). Cone beam computed tomography (CBCT) measurements were used to assess the buccolingual inclination of the axis of the maxillary and mandibular first molars, as well as the buccolingual inclination of the alveolar bone, the dental arch width, and the basal bone width. One-way ANOVA, the LSD test, and Pearson correlation analysis were performed. RESULTS: The high-angle group showed significantly greater lingual inclination of the maxillary alveolar bone than the low-angle group and average-angle group (p < 0.001; p < 0.05). The difference in buccolingual inclination of the axis of the maxillary first molar and the alveolar bone was significantly greater in the high-angle group than in the low-angle group (p < 0.05). Both the maxillary and mandibular dental arch were significantly narrower in the high-angle group than in the other two groups. The mandibular basal bone was also significantly narrower in the high-angle group than in the low-angle group and average-angle group (p < 0.001; p < 0.01). CONCLUSIONS: The alveolar bone of maxillary first molar in the high-angle group was more palatal inclined than that the low-angle group and the average-angle group, which suggests that orthodontists should pay more attention to the root-bone relationship in the high-angle group during expansion treatment to prevent bone fenestration and dehiscense.

Simulating the Entire Clinical Process for an Implant-Supported Fixed Prosthesis: In Vitro Study on the Vertical Implications of Implant-Abutment Connections and Rotational Freedom.

OBJECTIVES: The aim of this in vitro study was to investigate whether and to what extent different scenarios of rotational freedom in different IAC designs affect the vertical dimension of a three-part fixed partial denture (FPD). At the same time, the experimental setup should simulate all clinical and laboratory steps of the implementation of such an FPD as accurately as possible. MATERIAL AND METHODS: Twenty identical pairs of jaw models were fabricated from aluminum, each lower-jaw model holding two implants with conical or flat IACs. Three impressions of each model were taken to fabricate stone casts and three-unit FPDs. Three assembly scenarios were compared for the vertical position stability they offered for these FPDs, differing by how the sequential implant components (impression posts > laboratory analogs > abutments 1 > abutments 2) were aligned with the positional index of the IAC. In this way, a total of 60 stone casts and FPDs were fabricated and statistically analyzed for changes in vertical dimension (p < 0.05). RESULTS: Regardless of whether a conical/flat IAC was used (p > 0.05), significantly greater mean changes in vertical dimension were consistently (all comparisons p < 0.0001) found in a "worst-case scenario" of component alignment alternating between the left- and right-limit stop of the positional index (0.286/0.350 mm) than in a "random scenario" of 10 dentists and 10 technicians with varying levels of experience freely selecting the alignment (0.003/0.014 mm) or in a "best-case scenario" of all components being aligned with the right-limit stop (-0.019/0.005 mm). CONCLUSIONS: The likelihood of integrating a superstructure correctly in terms of vertical dimension appears to vary considerably more with assembly strategies than with IAC designs. Specifically, our findings warrant a recommendation that all implant components should be aligned with the right-limit stop of the positioning index.

Dentoalveolar bone height in Class I adults with different vertical patterns: A cross-sectional study.

BACKGROUND: Facial divergence during growth and development affects both the anterior and posterior alveolar bone dimensions in the maxilla and mandible, and the dentoalveolar compensation mechanism in severe vertical skeletal discrepancies remains unclear. AIMS: To evaluate the: (1) difference in dentoalveolar heights among subjects with different vertical facial patterns; (2) association between the dentoalveolar bone height and other cephalometric variables; (3) effect of sex on dentoalveolar height measurements. MATERIAL AND METHODS: Non-growing subjects with skeletal Class I (0°

Prospective case series study on the survival rates of occlusal polymethyl methacrylate veneers as a semipermanent therapy in patients with severe pathologic tooth wear.

OBJECTIVES: To evaluate the survival rate of minimally invasive semipermanent occlusal polymethyl methacrylate (PMMA) onlays/veneers in previous temporomandibular disorder (TMD) patients with severe tooth wear and with a loss of vertical dimension after up to 7 years. METHOD AND MATERIALS: This case series was designed as a follow-up evaluation with consecutive patient recruitment. All patients bearing the indication for this kind of rehabilitation were treated by the same clinician using the same adhesive methodology. The study included 22 patients (3 men/19 women), with a mean ± SD age of 50.7 ± 11.6 years. Controls followed within the first 4 weeks (and subsequently as required). Failure criteria included damage by fracture, chipping, and retention loss. Survival rates were determined based on the Kaplan-Meier analysis. RESULTS: 328 semipermanent occlusal/incisal veneers were included (142 maxillary/186 mandibular teeth). Almost 80% of the restorations were in place and in function when starting the follow-up treatment after 180 days; failures predominantly occurred within the first 3 to 6 months but proved reparable. Depending on the patients' priorities, scheduled replacements followed successively, and more than 65% did not show repair or any renewal needs for more than 360 days. CONCLUSION: Within the limitations of this study the survival rates of occlusal veneers made of PMMA were sufficiently high to allow for consecutive treatment of the respective teeth by means of permanent restorations while preserving the restored vertical dimension. In patients with severe tooth wear and a TMD history, semipermanent restorative therapy with occlusal PMMA onlays/veneers would seem a noteworthy option.

Vertical Mouth Opening Requirements for CAD/CAM Fully Guided Implant Surgery: An Analysis of Different Implant Systems.

PURPOSE: To determine the vertical space required for implant osteotomy preparation when utilizing a CAD/CAM fully guided surgical template. MATERIALS AND METHODS: A total of 14 surgical osteotomy drills (individual and sequential drills) were collected and measured individually using a digital caliper, as well as the total length when the drills were positioned in a surgical handpiece. The height of the surgical guide sleeves and the offset of 14 implant systems in the market were also collected. RESULTS: The vertical dimension of the drills included in this study ranged from 28.2 to 46.3 mm. When these drills were inserted into the handpiece, the total length ranged from 30.0 to 49.5 mm. The height of the surgical guide sleeve and the offset required for the guide had a range of 3.2 to 7.0 mm and 5.0 to 13.5 mm, respectively. This dimension resulted in the total vertical space required for CAD/CAM fully guided surgical templates for each implant system, which ranged from 30.0 to 58.5 mm. CONCLUSIONS: Limited mouth opening can pose challenges and limitations in both guided and nonguided dental implant surgery. It can affect the accessibility of surgical implant placement and may result in increased patient discomfort, surgical implant positioning errors, and postoperative complications. Clinicians should determine the patient's mouth opening capabilities during the treatment planning phase prior to deciding on the appropriate implant system to be used and the implant placement technique.

Uso de overlays controlados electromiográficamente y su combinación con el tratamiento con alineadores / Use of electromyographically controlled overlays and their combination with and its combination with treatment with aligners

La dimensión vertical (DV) usualmente disminuye con el paso del tiempo y es uno de los objetivos más complicados en resolver en los casos de Ortodoncia, ya sea con brackets o con alineadores. Esta disminución de la DV tiene una influencia directa en el funcionamiento de la articulación temporomandibular (ATM). Las patologías de la ATM, que surgen por la pérdida de la DV, son usualmente tratadas en la fase I con placas que restablecen la posición articular y la función muscular. Luego de corregida la patología de la ATM, en la fase II hay que tratar en lo posible la oclusión, devolviendo al paciente un soporte fisiológico posterior. Aquí se presenta un caso clínico atendido con una Placa Neurofisiológica (PN) en la fase I, y en la fase II, el traslado de esta altura a los overlays (O) y su erupción posterior dentaria con alineadores. Controlando cada paso electromiográficamente para el restablecimiento y control de la función muscular.

The vertical dimension usually decreases over time and is one of the most complicated objectives to solve in Orthodontic cases, whether with braces or aligners. This decrease in vertical dimension has a direct influence on the physiology of the temporomandibular joint. TMJ pathologies that arise from the loss of vertical dimension are usually treated in Phase I with splints that restore joint position and muscle function. After correcting the TMJ pathology, in Phase II, the occlusion should be treated as much as possible, returning the patient to a physiological posterior support. A clinical case is presented involving treatment with a Neurophysiological Splint in the first phase, and in the second phase, the transfer of this height to overlays and subsequent dental eruption with aligners. Each step is electromyographically monitored for the restoration and control of muscle function.

Influence on the temporomandibular joint induced by mandibular malpositioning caused by vertical dimension elevation and occlusal loss in adult rats: An imaging, histological and immunohistochemical study.

BACKGROUND: Mandibular malpositioning may result in an abnormal concentration of stresses within the temporomandibular joint (TMJ) in adult rats, which may further lead to a series of pathological changes, such as articular cartilage wear, subchondral bone sclerosis and osteophyte formation. However, the pathological and adaptive changes in condylar cartilage caused by different stress distributions are still controversial. OBJECTIVE: The aim of this study was to observe the effect of sagittal changes in mandibular position on condylar cartilage by changing the occlusal vertical dimension (OVD) in adult rats. METHODS: Fifteen-week-old female rats were divided into three groups: control (CON), increased OVD (iOVD) and loss of occlusion (LO) groups. An occlusal plate and tooth extraction were used to establish the animal model. TMJ samples of the experimental and CON groups were observed and investigated by bone morphological, histomorphological and immunohistochemical staining analyses at 3 days, 1 week, 2 weeks, 4 weeks and 8 weeks. Weight curves were plotted. RESULTS: Micro-computed tomography showed that, compared with the CON group, cartilage destruction followed by repair occurred in both experimental groups, which was similar to the trend observed in haematoxylin-eosin staining. All experimental results for the iOVD group showed an approximately similar time trend. Compared with the iOVD group, the toluidine blue and immunohistochemical staining results in the LO group showed no obvious change trend over time. CONCLUSION: Compared with occlusal loss, an increase in OVD caused faster and more severe damage to condylar cartilage, and subchondral bone repair occurred later.

Comparison of treatment effects between clear aligners and fixed appliances in patients treated with miniscrew-assisted molar distalization.

OBJECTIVES: The biomechanics in achieving molar distalization may differ between fixed appliances and clear aligners in the control of tooth movement. The objective of this study was to compare the treatment effects between clear aligners (CA) and fixed appliances (FA) in patients treated with miniscrew-assisted molar distalization. METHODS: The sample consisted of 46 subjects with mild-to-moderate crowding. A total of 22 patients treated with clear aligners (age, 25.66 ±â€…6.11 years old) and 24 patients treated with fixed appliances (age, 24.04 ±â€…4.95 years old) for miniscrew-assisted molar distalization were included in this study. The dental and skeletal changes were evaluated by the pre- and post-treatment lateral cephalograms. RESULTS: Significant changes were found with the vertical variables SN-OP angle (2.24 ±â€…3.22°, P < .05) and SN-MP angle (0.73 ±â€…1.15°, P < .05) for the FA group when compared with the CA group (SN-OP angle 0.41 ±â€…2.26° and SN-MP angle -0.21 ±â€…1.38°, P > .05). Both treatment groups achieved a 2-3 mm. molar distalization with significant intrusion of the upper molars. The CA group showed significantly less distal tipping of molars (U6^PP angle -2.29 ±â€…3.29° and L6^MP angle -2.92 ±â€…2.49°, P < .05) compared to the FA group (-5.24 ±â€…4.28° and -5.53 ±â€…5.03°, P < .05). In addition, significant retraction and lingual inclination of the upper and lower incisors were found in both groups. LIMITATIONS: The changes of tooth position were evaluated by 2D lateral cephalograms, not 3D measurements. CONCLUSIONS: Compared to fixed appliances, clear aligners seemed to have better control of vertical dimension and distal tipping of molars in patients treated with miniscrew-assisted molar distalization.

Quantitative evaluation of vertical control in orthodontic camouflage treatment for skeletal class II with hyperdivergent facial type.

BACKGROUND: In this study, we sought to quantify the influence of vertical control assisted by a temporary anchorage device (TAD) on orthodontic treatment efficacy for skeletal class II patients with a hyperdivergent facial type and probe into the critical factors of profile improvement. METHODS: A total of 36 adult patients with skeletal class II and a hyperdivergent facial type were included in this retrospective case-control study. To exclude the effect of sagittal anchorage reinforcement, the patients were divided into two groups: a maxillary maximum anchorage (MMA) group (N = 17), in which TADs were only used to help with anterior tooth retraction, and the MMA with vertical control (MMA + VC) group (N = 19), for which TADs were also used to intrude the maxillary molars and incisors. The treatment outcome was evaluated using dental, skeletal, and soft-tissue-related parameters via a cephalometric analysis and cast superimposition. RESULTS: A significant decrease in ANB (P < 0.05 for both groups), the retraction and uprighting of the maxillary and mandibular incisors, and the retraction of protruded upper and lower lips were observed in both groups. Moreover, a significant intrusion of the maxillary molars was observed via the cephalometric analysis (- 1.56 ± 1.52 mm, P < 0.05) and cast superimposition (- 2.25 ± 1.03 mm, P < 0.05) of the MMA + VC group but not the MMA group, which resulted in a remarkable decrease in the mandibular plane angle (- 1.82 ± 1.38°, P < 0.05). The Z angle (15.25 ± 5.30°, P < 0.05) and Chin thickness (- 0.97 ± 0.45°, P < 0.05) also improved dramatically in the MMA + VC group, indicating a better profile and a relaxed mentalis. Multivariate regression showed that the improvement in the soft tissue was closely related to the counterclockwise rotation of the mandible plane (P < 0.05). CONCLUSIONS: TAD-assisted vertical control can achieve intrusion of approximately 2 mm for the upper first molars and induce mandibular counterclockwise rotation of approximately 1.8°. Moreover, it is especially important for patients without sufficient retraction of the upper incisors or a satisfactory chin shape.

Reliability of a face scanner in measuring the vertical dimension of occlusion.

OBJECTIVE: This study evaluated the reliability of a face scanner in measuring the vertical dimension of occlusion (VDO). METHODS: Fully dentate volunteers (n = 20; mean-age = 30.0 ± 10.7 years) were recruited. Clinical facial measurements were obtained using a digital caliper and a face scanner (Obiscanner, Fifthingenium, Italy). The scans were imported into a mesh-processing software, and the distances were measured digitally. Measurements were obtained for each participant with the jaws positioned in maximal intercuspation (MI) and with increased vertical distances of 2, 4, and 6 mm. Vertical and horizontal measures were obtained using facial anatomical landmarks: Glabella (GL), Pronasale (PrN), Subnasale (SbN), inferior border of the right and left Alare, Labiale superius (Ls), right and left Cheilion (Ch), Soft Pogonion (SPg), right and left Tragus of the ear (Tr), for all selected vertical positions. Data analysis included intra-class correlation coefficient (ICC), pairwise comparison tests, Bland-Altman plots, and Passing-Bablok regression. RESULTS: 120 VDO measurements (clinical=60, digital=60) were recorded by two independent evaluators. Mean differences between digital and clinical measurements ranged from 0.054 ± 0.14 mm to 0.203 ± 0.13 mm. All parameters were strongly correlated (r > 0.93; p < 0.001). ICC estimates revealed excellent reliability, and the measuring procedure yielded the same results on repeated trials irrespective of the raters and measurement methods. Bland-Altman plots revealed a difference, between digital and clinical measurements, of 1.7 % for the vertical measurements. Regression analysis revealed no significant proportional difference between the two methods, so both can be used interchangeably. CONCLUSIONS: The findings of this study demonstrate that VDO can be measured accurately from face scans using 3D mesh-processing software and that even small changes in the VDO could be detected using the digital methods. CLINICAL SIGNIFICANCE: Findings provide evidence about the reliability of a digital method for jaw relation registrations and may be applied towards incorporating this method into clinical workflows for computer-aided-design/ computer-assisted-manufacturing (CAD-CAM) dentures.

Comparison of the accuracy of different types of bite recordings - an in vitro study.

OBJECTIVES: Reconstruction of a three-dimensional jaw position determined by a bite recording is an important aspect of prosthetic therapy. Different materials are used for this purpose. In the dental technical workflow, recordings are used to mount a lower jaw cast in a patient-like spatial position relative to the upper jaw cast. We evaluated the accuracy of positioning under the influence of different jaw positions and materials. MATERIALS AND METHODS: In an experimental setup, comprising an articulator, a pair of metal casts, and an optoelectronic measurement system, the spatial position of the incisal point and two condylar points were measured. To evaluate the accuracy of repeated repositioning of casts in the technical workflow, 324 measurements were taken from 108 recordings, consisting of silicone bite-stops made of addition curing silicone with 95 shore hardness, acrylic wafers, and wax recordings. The recordings were obtained in four jaw relations differing in vertical and protrusive components. RESULTS: Of the three materials/material combinations examined, silicone showed the most consistent results across all measurements, followed by the acrylic wafer system, and then wax recordings. Generally, recordings with smaller gaps between the jaws and no protrusive components showed greater deviations compared to jaw positions with greater protrusion and higher vertical dimensions. CONCLUSIONS AND CLINICAL RELEVANCE: To achieve reliable model mounting with high accuracy, recordings should include the use of a frontal jig and four small recording platelets made of silicone, especially if only a slight elevation of the vertical dimension is needed.