Stress Distribution within the Peri-Implant Bone for Different Implant Materials Obtained by Digital Image Correlation.

Stress distribution and its magnitude during loading heavily influence the osseointegration of dental implants. Currently, no high-resolution, three-dimensional method of directly measuring these biomechanical processes in the peri-implant bone is available. The aim of this study was to measure the influence of different implant materials on stress distribution in the peri-implant bone.

Three-dimensional analysis of the accuracy of conventional and completely digital interocclusal registration methods.

Statement Of Problem: Compared with the frequent investigations into the accuracy of digital intraoral scans, studies analyzing digital determinations of jaw relationships based on intraoral scans are scarce.

Purpose: The purpose of this in vitro study was to present an optical 3-dimensional method for analyzing deviations in static occlusion and to compare the accuracy of conventional and digital interocclusal registrations.

Material And Methods: A Frasaco jaw model was duplicated, articulated, and scanned with a high-precision industrial scanner, and the data were stored in a virtual standard tessellation language (STL) format, which served as the reference model.

3D-based full-guided ridge expansion osteotomy - A case report about a new method with successive use of different surgical guides, transfer of splitting vector and simultaneous implant insertion.

For horizontal bone deficiency alveolar ridge osteotomy is considered an option for augmentation. Major advantages are the option for a one-stage approach and the absence of donor site morbidity. However, the conventional technique is associated with complications such as perforations and fractures of the cortical bone.

Hygroscopic expansion of self-adhesive resin cements and the integrity of all-ceramic crowns.

Objective: Low pH neutralization and subsequent remnant hydrophilicity can lead to hygroscopic expansion of self-adhesive resin cements (SARCs) after water storage. The aim of this in vitro study was to investigate the effects of hygroscopic expansion of SARCs, used as luting and partial core build-up material, on integrity and cement gap thickness increase of all-ceramic CAD/CAM crowns.

Methods: Human third molars (n=48) were prepared and anatomical all-ceramic CAD/CAM crowns were manufactured (VITABLOCS Mark II, VITA Zahnfabrik).

Afferent sensory mechanisms involved in jaw gape-related muscle activation in unilateral biting.

Objectives: In unilateral biting or chewing, the working/balancing-side ratio (W/B-ratio) of masseter activities is inversely proportional to the jaw gape which was interpreted as a neuromuscular strategy to protect occlusion. This suggests that jaw separation is afferently perceived, raising the question how this perception might work. In related studies, isometric biting was exerted on rubber pieces that slightly yielded similar to compressed food in chewing.

Correlations between tooth mobility and the Periotest method in periodontally involved teeth.

Objective: The aim of this clinical study was to evaluate whether a correlation exists between three-dimensional tooth mobility (TM) and Periotest values for maxillary anterior periodontally involved teeth (pocket depth > 3 mm) before and after periodontal therapy.

Method And Materials: Force-related TM was measured in 3 N intervals in 19 participants as they bit down on a load cell. Periotest values were evaluated at reproducible measurement points.

Influence of attachment and bone loss on the mobility of incisors and canine teeth.

Objective: The purpose of this clinical study was to evaluate the correlation between tooth mobility (TM), crown-to-root ratio (CRR) and clinical attachment loss (CAL) in periodontally-compromised participants.

Materials And Methods: While slowly biting on a load cell, the mobility of the upper incisors and canine teeth of 20 volunteers was measured using a photogrammetric measurement technique. An automated software program recorded the force-related three-dimensional TM at 3-N intervals.

A technique for in vitro fit assessment of multi-unit screw-retained implant restorations: Application of a triple-scan protocol.

Recent advances in industrial non-contact scanners offer unprecedented opportunities for quality assessment of dental restorations. The majority of investigations published to date are limited to local two-dimensional results. A triple-scan protocol for virtual fit assessment of multi-unit screw-retained implant restorations is presented in this technical report.

Neuromuscular control of balancing side contacts in unilateral biting and chewing.

When jaw gape in unilateral biting or chewing narrows, the working/balancing side activity ratio (W/B ratio) of masseter muscles increases due to decrease of balancing side (BS) activity. This was interpreted as a neuromuscular strategy to delimit the impact of BS contacts during chewing. To test this hypothesis, we studied whether W/B ratios are associated with incidence of BS tooth contacts.

A new triple-scan protocol for 3D fit assessment of dental restorations.

Objective: Assessing the level of precision entailed by the virtual fit of dental restorations is a very challenging issue. A cement space between an abutment tooth and a dental restoration is a clinical requisite that precludes the application of conventional best-fit registration protocols routinely applied in industrial precision measurements. Since two-dimensional fit assessment techniques currently used in dentistry miss important information about the third dimension, a new protocol was developed to provide three-dimensional information for the virtual registration of the digitized restoration with respect to the abutment.

Five-year clinical follow-up of prefabricated precision attachments: a comparison of uni- and bilateral removable dental prostheses.

Objectives: To evaluate the clinical long-term success of prefabricated precision attachments in retaining uni- or bilateral removable dental prostheses.

Method And Materials: Twenty-three patients with uni- or bilateral shortened dental arches received removable dental prostheses attached to the residual dentition with two types of precision attachments.

Results: After 5 years, 70% of bilateral and 25% of unilateral removable dental prostheses remained clinically functional.

Correlations between photogrammetric measurements of tooth mobility and the Periotest method.

Objective: The purpose of the present study was to investigate whether or not the quantitative Periotest values of anterior teeth correlate with quantitative metric values of tooth mobility under vertical (VL) and horizontal load (HL) in periodontally healthy subjects.

Materials And Methods: Thirty-one subjects with good periodontal conditions were included and subjected to two different tooth mobility measurement techniques. Periotest values were measured at reproducible measurement points in the vertical (vPT) and horizontal (hPT) dimensions of upper central and lateral incisors and canine teeth.

The effect of axial and oblique loading on the micromovement of dental implants.

Purpose: To quantify implant displacement upon axial and oblique force application and compare the effects of bone quality using an in vitro experimental setup.

Materials And Methods: One hundred ninety-two implants were inserted into artificial bone block specimens using a drill guide. Ninety-six implants were placed in soft cancellous bone and loaded in 10-N increments up to 80 N in axial and oblique (30-degree angle) directions (n = 48 in each group).

Photogrammetric measurement of initial tooth displacement under tensile force.

The purpose of this study was to quantitatively measure tooth displacement under low horizontal tensile force (≤18 N) and to test the reproducibility of measurements. Anterior tooth mobility was measured using a photogrammetric measurement technique in 23 periodontally healthy subjects. While slowly increasing the tension on each tooth, an automated software program recorded three-dimensional tooth displacement at 3 N intervals, up to 18 N.

Impact of arbitrary and mean transfer of dental casts to the articulator on centric occlusal errors.

When fabricating dental restorations, casts are usually transferred to the articulator based on arbitrary hinge axes or mean values instead of true hinge axis points. Using arbitrary hinge axis points or mean values can lead to occlusal errors if the vertical relation is changed in the articulator (e.g.

Indications for jaw gape-related control of relative muscle activation in sequent chewing strokes.

Jaw muscle activity ratios in unilateral isometric biting differ from ratios of unilateral chewing but approach the latter if the jaw gape in biting is made as small as the minimum interocclusal distance (MID) of chewing. Especially, the masseter working/balancing side ratio (W/B-ratio) becomes as asymmetric as in chewing, because of reduction in balancing side (BS) masseter activity. This behaviour of ratios might reflect a 'chewing-specific' motor strategy induced when isometric biting is performed with a 'chewing-like' gape.

Noncontact intraoral measurement of force-related tooth mobility.

The aim of this pilot study was to measure force-related tooth mobility. Vertical and horizontal anterior tooth mobility in 31 healthy periodontal subjects was measured by a noncontact optical measurement technique. The subjects continuously increased the force on each tooth by biting on a load cell.

The effect of provisional restoration type on micromovement of implants.

Statement Of Problem: The osseointegration or fibrous encapsulation of immediately loaded dental implants depends largely on the extent of implant micromovement. The impact of acrylic resin or metal-reinforced acrylic resin provisional restorations on this movement is currently unknown.

Purpose: The purpose of this study was to isolate and measure the effect of provisional restoration type on the vertical displacement of adjacent implants under load at 2 locations.

Motor control of jaw muscles in chewing and in isometric biting with graded narrowing of jaw gape.

When a certain bite force is applied during unilateral chewing, the combination of jaw elevator muscle activities is different than when a comparable force is applied in unilateral isometric biting, e.g. on a force transducer.

Comparison of PAC and QTH light sources on polymerization of resin composites.

Purpose: To evaluate the polymerization shrinkage, Knoop hardness number (KHN) and compressive strength and to suggest a suitable time for irradiating resin composite restorations, when using a high-intensity light source.

Methods: Two restorative resin composites, UniFil F, and Clearfil AP-X were employed. A high-intensity light unit (more than 1000mW/cm2) with a xenon discharge lamp (Apollo 95E), which is generally called a plasma arc light-curing unit (PAC), was compared with a conventional light-curing unit fitted with a quartz-tungsten-halogen lamp (QTH) (GC Newlight VL2).

The partial overdenture in management of anterior apertognathia: a clinical report.

A patient with anterior apertognathia presented with an unserviceable maxillary removable partial denture. The unique pattern of partial edentulism was treated with a partial overdenture restoration of the bar attachment design. The final prosthesis was stable, well retained, and esthetic, serving as a conservative alternative to a surgical-orthognathic plan of treatment.