Kurtz Kenneth S

Kurtz Kenneth S

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Kurtz Kenneth S

Publications Authored By Kurtz Kenneth S

To compare the removal of torque values of machined implant abutment connections (internal and external) with and without soft tissue entrapment using an in vitro model.
Thirty external- and 30 internal-connection implants were embedded in urethane dimethacrylate. Porcine tissue was prepared and measured to thicknesses of 0.Read More

5 and 1.0 mm. Six groups (n = 10) were studied: External- and internal-connection implants with no tissue (control), 0.5, and 1.0 mm of tissue were entrapped at the implant/abutment interface. Abutments were inserted to 20 Ncm for all six groups. Insertion torque values were recorded using a digital torque gauge. All groups were then immersed in 1 M NaOH for 48 hours to dissolve tissue. Subsequent reverse torque measurements were recorded. Mean and standard deviation were determined for each group, and one-way ANOVA and Bonferroni test were used for statistical analysis.
All 60 specimens achieved a 20-Ncm insertion torque, despite tissue entrapment. Reverse torque measurements for external connection displayed a statistically significant difference (p < 0.05) between all groups with mean reverse torque values for the control (13.71 ± 1.4 Ncm), 0.5 mm (7.83 ± 2.4 Ncm), and 1.0 mm tissue entrapment (2.29 ± 1.4 Ncm) groups. Some statistically significant differences (p < 0.05) were found between internal-connection groups. In all specimens, tissue did not completely dissolve after 48 hours.
External-connection implants were significantly affected by tissue entrapment; the thicker the tissue, the lower the reverse torque values noted. Internal-connection implants were less affected by tissue entrapment.

J Prosthodont
J Prosthodont 2016 Mar 21. Epub 2016 Mar 21.
Division of Maxillofacial Prosthetics, Stony Brook University School of Dental Medicine, Stony Brook, NY.

Relief of the intaglio surface of a denture base is conventionally performed using thin wax and soft metal foil attached to the master cast. The following report highlights a new relief procedure for the mental foramen using a CT double scan technique on the CAD/CAM dentures fabricated for the patient with paresthesia of the left lower lip and chin during mastication.Read More

ᅟ: The purpose of the current study was to determine the accuracy of the clinical diagnosis in non-melanoma skin malignancy as confirmed by histopathological examination of the specimen. Positive predictive value (PPV) was selected as a reliable measure of diagnostic accuracy.
Clinical diagnosis was made in the outpatient clinic by a consultant oral and maxillofacial surgeon.Read More

We reviewed the electronic charts of 210 patients with non-melanoma skin malignant tumours and calculated the positive predictive value of the initial clinical diagnosis. Histological confirmation for each lesion was compared with the provisional clinical diagnosis made in the clinic.
Of the 147 lesions provisionally diagnosed as basal cell carcinomas, 133 lesions were histologically confirmed to be basal cell carcinomas (BCC) (PPV 90.4 %). Of the 63 lesions provisionally thought to be squamous cell carcinomas, 47 lesions were histologically confirmed as squamous cell carcinomas (SCC) (PPV 74.6 %). The difference between the PPVs for the two types of malignancy in our study was not significant (p = 0.39). Statistics between our results for BCC and SCC and those reported from two other cancer institutes revealed no significant difference (p = 0.58 and 0.07).
The present study supports that relying on clinical diagnosis with the purpose to formalise a treatment plan for head and neck non-melanoma skin cancer is safe and efficient. This is more reliable in cases of basal cell carcinoma in comparison to suspected squamous cell carcinomas. Although positive predictive value represents a reliable measure of diagnostic accuracy, it is increased when populations with higher prevalence of the disease are studied.

The socket or ridge preservation approach known as the "ice cream cone" technique was used in type 2 sockets in this retrospective analysis of 11 extraction sites. A type 2 extraction socket is defined as having the presence of facial soft tissue with a partial or complete dehiscence of the buccal bone plate. All teeth were extracted atraumatically without flap elevation.Read More

A resorbable collagen membrane was contoured into an ice cream cone- shape, placed into the socket defect, and grafted with human freeze-dried bone allograft. Buccolingual dimensional changes were measured manually with a digital caliper sensitive to 0.01 mm on pre- and posttreatment casts using an acrylic template and a three-dimensional (3D) digital scanner, as well as radiographically with pre- and post-cone beam computed tomography (CBCT) scans. All implants were placed 6 months after socket preservation and achieved primary stability with a minimum torque value of 35 Ncm with a mean buccal-lingual dimensional loss of 1.32 mm. The dimensional change of the ridge from pre- to postextraction reflective of the healed grafted site ranged from a loss of 0.46 to 2.25 mm with a mean of 1.28 mm (CBCT), 0.31 to 2.71 mm with a mean of 1.36 mm (digital calipers), and 0.21 to 2.80 mm with a mean of 1.32 mm (3D digital scanner). All 11 implants were immobile and clinically osseointegrated. The so-called ice cream cone technique allows for the reconstruction of a buccal plate dehiscence to enable the placement of an implant; however, the ridge dimension was diminished by 1.32 mm compared with the width of the extraction socket prior to tooth removal.

Br J Oral Maxillofac Surg
Br J Oral Maxillofac Surg 2013 Oct 15;51(7):669-70. Epub 2013 May 15.

Accurate and timely collection of clinical records is of utmost importance in planning, evaluating, and auditing orthognathic operations. The minimum dataset guidelines of the British Orthodontic Society (BOS) and the British Association of Oral and Maxillofacial Surgeons (BAOMS) were published in an attempt to standardise the collection of clinical records of patients having orthognathic operations. This multicentre retrospective audit aimed to assess and compare compliance with the guidelines in 3 maxillofacial units over a 1-year period.Read More

A total of 105 cases were reviewed. Compliance varied. Documentation of altered sensation was consistently poor and too many unnecessary radiographs were taken. There may be a need to circulate the guidelines again to increase awareness and reduce variability between centres.

J Prosthodont
J Prosthodont 2013 Jul 6;22(5):397-401. Epub 2013 Feb 6.
Resident in Graduate Prosthodontics, New York Hospital, Queens, NY, USA.

Patients who have had a partial or full surgical resection of the maxillary or mandibular lip experience difficulties with articulation of speech, swallowing, and salivary control. This is further complicated by significant alterations in facial esthetics and lowered self-esteem. This clinical treatment will describe the fabrication of a two-piece tooth-retained maxillofacial prosthesis.Read More

An intraoral retentive portion and an extraoral section restoring lip anatomy were attached by retentive elements. This prosthesis restored the patient's esthetics, oral function, and self-esteem.

J Prosthodont Res
J Prosthodont Res 2013 Apr 13;57(2):140-4. Epub 2013 Mar 13.
Division of Oral and Maxillofacial Implantology, Tsurumi University School of Dental Medicine, Yokohama, Japan. suzuki-ys@tsurumi-u.ac.jp

The patient was a 62-year-old partially edentulous woman with missing bilateral premolars and molars in the mandibular jaw. The patient selected implant supported-removable partial denture rehabilitation. Implants were placed bilaterally at the distal extension of the denture base in order to minimize denture displacement.Read More

The stress-breaking ball (SBB) attachment consists of a flat-top ball head male and O-ring rubber female. The female was covered by a silicone housing with three amounts of space to allow three kinds of settlement (0.3 mm, 0.5 mm, and 0.7 mm); they were selected by thickness or pressure displacement of the mucosa and occlusal force. After the healing period, the SBB attachments (0.3 mm) were placed on the implants, and the implant-supported removable partial denture was then conventionally fabricated. The delivered denture had sufficient retention and appropriate stress breaking.
The advantages of SBB attachments over conventional attachments are as follows: (1) they prevent the implant from excessive occlusal force, (2) they are ready-made, (3) they show appropriate retention, and (4) they can be easily mounted on the denture base. The disadvantages of these attachments are as follows: (1) they are approximately 1mm higher than conventional ball attachments and (2) the retentive force cannot be adjusted.
The use of a stress-breaking attachment for implant overdenture rehabilitation should be considered so that the occlusal force is equally distributed between the alveolar ridge and the implants.

J Prosthodont Res
J Prosthodont Res 2012 Oct 18;56(4):293-6. Epub 2012 May 18.
Division of Oral and Maxillofacial Implantology, Tsurumi University School of Dental Medicine, Yokohama, Japan. suzuki-ys@tsurumi-u.ac.jp

The patient was partially edentulous, lacking both the first mandibular molars. The FBI and the conventional impression technique were used for the fabrication of implant-fixed prosthesis replacing the right and left molars, respectively. In the FBI technique, the definitive impression was made under occlusal force and functionally generated path (FGP) recording at the same time.Read More

The right and left occlusal contact areas were compared after completing the implant-fixed prosthesis rehabilitation.
It has been suggested that accuracy of the impression and maxillomandibular registration is necessary to ensure a satisfactory long-term clinical outcome. The transfer of the exact position of the implants to the working cast is even more important because implants lack the mobility of natural teeth. There are displacement differences between implants and natural teeth under occlusal force. The FBI technique may compensate for this difference in accuracy.
Using the FBI technique, a precise prosthesis could be produced by completing simultaneously the maxillomandibular registration, impression and FGP.

J Prosthodont
J Prosthodont 2011 Oct;20 Suppl 2:S20-5
Advanced Education Program in Prosthodontics, New York University College of Dentistry, New York, NY, USA.

This case report presents treatment of two patients with the usual characteristics of Cleidocranial Dysostosis. A multidisciplinary approach using the disciplines of prosthodontics, orthodontics, and oral surgery was effected. Exfoliation of the patient's deciduous teeth and failure of permanent anterior tooth eruption led to emotional, social, and self-esteem issues in both patients.Read More

Due to the psychosocial issues confronting these two patients, esthetics was addressed prior to active intervention with orthodontics and after some surgical intervention. The use of two interim overdenture prostheses with magnetic retention is described.

J Prosthodont
J Prosthodont 2011 Jul 17;20(5):348-54. Epub 2011 May 17.
Montefiore Medical Center/Albert Einstein College of Medicine, Division of Prosthodontics, Department of Dentistry, Bronx, NY 10467, USA.

To investigate the effects of internally connected engaging component position in screw-retained fixed cantilevered prostheses.
Twenty-one three-unit fixed dental prostheses (FDPs) were cast in high-palladium alloy in three groups. In group A, engaging components were incorporated into the units away from the cantilevered segment; proximal units received nonengaging components.Read More

In group B, these positions were reversed. Control specimens were fabricated using all nonengaging components. Specimens were attached to internally connected 3.5 (diameter) × 13 mm (length) implants, torqued to 32 Ncm, and embedded into epoxy resin. Specimens were tested in cyclic fatigue with a 2 Hz sine wave and 0.1 min/max load ratio. Load amplitude started at 1.8 N and increased by 1.8 N every 60 cycles until fracture. Log-rank statistic, ANOVA, Spearman's correlation, and LIFETEST procedures were used to evaluate level of statistical significance within the results.
In the control group, the mean number of cycles to fracture was 31,205 ± 2639. Mean axial force at fracture was 932 ± 78 N. In group A, these numbers were 38,160 ± 4292 and 1138 ± 128 N, and in group B, 31,810 ± 3408 and 949 ± 101 N. Statistical significance levels for number of cycles to fracture were: Control versus group A, p = 0.0117, and groups A versus B, p = 0.0156 (statistically significant). Control versus group B, p = 0.357 (not statistically significant). Log-rank statistic for the survival curves is greater than would be expected by chance; there was a statistically significant difference between survival curves (p = 0.012). The location and mode of failure were noteworthy (always in the abutment screw).
The position of the engaging component had significant effects on the results. Within the limitations of this investigation, it can be concluded that using an engaging abutment in a screw-retained fixed cantilevered FDP provides a mechanical advantage, and engaging the implant furthest from the cantilever when designing a screw-retained cantilever FDP increased resistance to fracture of the distal abutment screw.

Eur J Prosthodont Restor Dent
Eur J Prosthodont Restor Dent 2011 Mar;19(1):2-6
Department of Dentistry, Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY, USA.

This study investigated the effect of laser treatment on the fatigue resistance of a 3.5-mm diameter implant with an internal trilobe connection. Twenty two implants were embedded into acrylic resin blocks.Read More

Half the specimens were used as control group, and the other half were laser treated circumferentially around the 1.5-mm polished collar with argon shielding. Implants were fatigue tested using a step-stress accelerated lifetime test in a servo-hydraulic test machine. Despite the trend pointing towards higher fatigue resistance of laser treated specimens versus controls, step-stress analysis did not determine significant differences in the fatigue lifetimes.

J Surg Case Rep
J Surg Case Rep 2010 1;2010(3). Epub 2010 May 1.

We discuss a case of idiopathic cervical epidural abscess, complicated by osteomyelitis, presenting with dysphagia as the main complaint. No predisposing factors were identified and blood cultures were negative. Case was treated conservatively by long course of IV antibiotics.Read More

We present a review of presentation of spinal epidural abscesses and indications for surgical intervention.

Eur J Prosthodont Restor Dent
Eur J Prosthodont Restor Dent 2009 Dec;17(4):188-91
Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan. Okubo-c@tsurumi-u.ac.jp

An implant-retained Konus (tapered double crown) telescopic complete overdenture was fabricated for a mandibular edentulous patient. The Konus telescopic overdenture coping crowns and framework assembly were cast with commercially pure (CP) titanium, joined using laser welding and placed on four one-piece implants. Sufficient retention and stability were obtained using this method.Read More

Dent Mater
Dent Mater 2009 May 4;25(5):629-33. Epub 2009 Jan 4.
Department of Biomaterials Science, Baylor College of Dentistry, Texas A&M Health Science Center, 3302 Gaston Ave., Dallas, TX 75246, USA. iwatanabe@bcd.tamhsc.edu

The aim of this study was to investigate the effect of laser surface treatment on the mechanical properties of cast titanium and to compare with those of the Co-Cr alloy.
Dumbbell-shaped cast specimens were prepared for commercially pure titanium (grade 2) and Co-Cr alloy. The cast titanium specimens were laser-treated on the surface using a dental Nd:YAG laser machine at 240 V and 300 V.Read More

After laser treatment, tensile testing was conducted to obtain the tensile strength, percent elongation and modulus of elasticity. The hardness depth profile was made from the cast subsurface (25 microm) to 1500 microm in depth using the cross-sections of the cast rods with the same diameter as the dumbbell. The data were statistically analyzed by ANOVA/post hoc tests (p<0.05).
The highest tensile strength was obtained for the titanium specimens laser-treated with 300 V followed by the 240 V and the control specimens. The laser-treated titanium specimens with 300 V showed a tensile strength equivalent to the Co-Cr alloy. Although the highest modulus of elasticity was found for the specimens laser-treated with 240 V, there were no significant differences in elastic modulus among 240 V, 300 V and Co-Cr. The laser-treated groups showed significantly lower hardness at the subsurface of 25 microm and maintained their hardness until the depth of 400 microm. The hardness of the control group was very high at 25 microm depth, and dramatically decreased until the 200 microm depth.
The results of tensile testing and hardness depth-profiling indicated that the laser treatment significantly improved the mechanical properties of cast titanium by improving the surface integrity of the cast surface contamination.

Quintessence Int
Quintessence Int 2007 Jul-Aug;38(7):e374-8
Division of Removable Prosthodontics, Department of Oral Rehabilitation, Fukuoka Dental College, Fukuoka, Japan. simizuh1@college.fdcnet.ac.jp

To evaluate the effect of the surface preparation of a gold cylinder on the failure probability of highly filled all-composite restorations used as implant-supported prostheses, and to determine the effect of the location of load application.
Gold cylinders (Nobel Biocare) were prepared with 1 of 4 different surface preparations (n = 20 per surface treatment), and then an indirect resin composite (Targis, Ivoclar Vivadent) was applied. The 4 surface treatment conditions were (1) untreated (prep 1); (2) airborne-particle abraded with 50-Microm alumina (prep 2); (3) airborne-particle abraded with 50-Microm alumina followed by application of a metal conditioner (Alloy Primer, J.Read More

Morita) (prep 3); and (4) airborne-particle abraded with 50-Mum alumina followed by application of the bonding primer for the indirect resin system (Targis Link) (prep 4). A compressive load was applied vertically at 1 mm and 2 mm from the access cavity on the occlusal surface until the restorations failed.
The prep 4 specimens had the highest fracture resistance. The fracture resistance at the 1-mm location was significantly higher than that at the 2-mm location. The failure load of the all-composite restorations with any of the surface preparations was lower than that of the resin-veneered restorations used as controls.
The prep 4 conditions decreased the probability of fracture of the highly filled all-indirect resin composite restorations. Eccentric loading of the all-composite restorations should be minimized in light of the higher probability of failure associated with such a loading condition.

J Dent
J Dent 2006 Feb 1;34(2):117-22. Epub 2005 Jul 1.
Division of Removable Prosthodontics, Department of Oral Rehabilitation, Fukuoka Dental College, 2-15-1 Tamura Sawara-ku, Fukuoka 814-0193, Japan. simizuh1@college.fdcnet.ac.jp

The shear bond strengths of an autopolymerizing denture base resin to cast Ti-6Al-7Nb and Co-Cr alloys using three metal conditioners were investigated.
Ti-6Al-7Nb alloy and Co-Cr alloy discs were cast. The disc surfaces were air-abraded with 50 microm alumina particles and treated with three metal conditioners (Alloy Primer; Cesead II Opaque Primer; Metal Primer II).Read More

An autopolymerizing denture base resin was applied on the discs within a hole punched in a piece of sticky tape and a Teflon ring to define the bonding area. All specimens were immersed in 37 degrees C water for 24 h. Half of the specimens were thermocycled up to 20,000 cycles. The shear bond strengths were determined at a crosshead speed of 1.0 mm/min.
Specimens treated with the three metal conditioners had significantly (p<0.05) improved shear bond strengths of the autopolymerizing denture base resin to both Ti-6Al-7Nb and Co-Cr. Although the bond strengths of the bonded Ti-6Al-7Nb specimens were higher than those of the Co-Cr alloy before thermocycling, the decrease in the bond strength of Ti-6Al-7Nb was considerably greater than that of the Co-Cr after thermocycling.
Significant improvements in bond strength of the autopolymerizing denture base resin to cast Ti-6Al-7Nb alloy and Co-Cr alloy were achieved through the application of Alloy Primer, Cesead II Opaque Primer and Metal Primer II. The bond durability to Ti-6Al-7Nb alloy was inferior to that to Co-Cr.

J Prosthet Dent
J Prosthet Dent 2005 Jan;93(1):24-7
Montefiore Medical Center/Albert Einstein College of Medicine (MMC/AECOM), Bronx, NY, USA. Dranupama1@aol.com

This report describes a method in which a customized carrier was fabricated for a patient experiencing difficulty during initial brachytherapy treatment, while using a conventional radiation carrier. When designing a customized brachytherapy carrier for a maxillary defect, it is imperative to achieve stability and retention to ensure maximal therapeutic radiation to the desired location. The fabrication and benefits of using a customized, retentive, stable, and comfortable orofacial brachytherapy carrier are described.Read More

J Prosthet Dent
J Prosthet Dent 2004 Feb;91(2):195-7
Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan. Okubo-c@tsurumi-u.ac.jp

The lack of proper stability and retention is frequently found in mandibular complete dentures. The stability and retention of existing complete dentures may be improved by using transitional implants (TIs) incorporating the O-ring retention system. This article describes the procedures used to convert an existing conventional complete denture to a TI-retained complete overdenture with O-ring.Read More

J Prosthet Dent
J Prosthet Dent 2003 Aug;90(2):201-4
Department of Removable Prosthodontics, Tsurumi Univeristy School of Dental Medicine, Yokohama, Japan. okubo-c@tsurumi-u.ac.jp

This article describes a sectional stock tray system developed by the authors for making preliminary impressions. It may be used not only for individual dental arches but also for patients with microstomia or constricted oral openings. This system allows many combinations of right and left tray sizes and forms to be assembled into a well-fitted anatomically-conforming tray in spite of individual anatomic discrepancies.Read More