Semiadjustable articulators are extensively used for routine restorative procedures. Prior to developing occlusion the condylar fossa mechanism of certain semiadjustable articulators (Whip-Mix, Denar Mark II, Dentatus ARH) are adjusted by the patient's lateral interocclusal records. The lateral interocclusal records are used to program the instrument for working condylar movement.

It has been reported in the literature that semiadjustable instruments do not accept lateral interocclusal records from all patients. Thus, the use of such instruments in fixed partial denture treatment may result in restorations with occlusal error for patient with immediate side shift, absence of immediate anterior disclusion, or severely worn dentition requiring posterior group function occlusion. The limited acceptability of lateral interocclusal records by the semiadjustable articulators, may also produce occlusal error in developing balanced occlusion in complete dentures.

To minimize the occlusal error, Hanau Modular System 194 semiadjustable articulator was introduced and the manufacturer recommends that the instrument may be adjusted by the use of lateral interocclusal records. In this instrument the condylar fossa mechanism is so designed to incorporate an adjustable immediate and progressive side shift which permits the working condylar element to follow a radial curve path as it shifts laterally.

Acceptability of lateral interocclusal records by Hanau Modular articulator was studied on 30 edentulous subjects. Face-bow registration was made for each subject. Split-cast technique was used to mount the final maxillary cast on the articulator. The mandibular cast was mounted using centric relation records. Central bearing device was employed to make centric relation and lateral interocclusal records.

The split-cast mounting permitted evaluation of lateral interocclusal records on the articulator. The union between the mounting and maxillary cast at four notches was visually noted and recorded as acceptable or unacceptable.

Out of 60 lateral interocclusal records made from 30 edentulous subjects 52 (87%) records were accepted by the Hanau Modular Articulator. By using "Z" test of one sample proportion, this value was statistically found to be highly significant (P< .00001). This study was supported by King Saud University, College of Dentistry Research Center Grant No. 1055.
Saudi Dental Journal 1994;6(SI)-Abstr.011:p11-12

This presentation will try to answer some of the common questions which may

arise during implant practice with respect to the selection of the proper implant according to various variables (i.e.) bone, location.

The presentation will stress on the importance of using a specific implant for each zone in the oral cavity. Also, a step by step procedure in some clinical cases with a quick review of old and new modalities.

Also included is a diagnostic procedure using panoramic X-rays and implant labels (I.V.A.S.). As well as a selection of implants according to the zone utilizing the wide scope provided by the Spectra System. A step by step clinical approach will be presented in management of clinical cases such as atrophic, resorbed mandibles, concerning diagnosis, surgery and prosthetic aspects.

Guidelines will be given for determining the best sequence of treatment in many different situations. Solutions to a number of typical cases will be presented in detail.
Saudi Dental Journal 1994;6(SI)-Abstr.012:p13

Abeds. Al-jabab*, E. Greener, E. Lautenschlager**,
*College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Kingdom of Saudi Arabia
**Northwestern University School of Dentistry, Chicago, Illinois, U.S.A.

Pure titanium metal has a great potential in dentistry. Its high melting point (1670oC) and reactivity with surrounding oxygen and investment material makes it very difficult to cast accurately. Since the reactivity of molten Ti with oxygen is a direct function of temperature, casts problems could be alleviated if a useful Ti-alloys, with a significantly lower casting temperature (110OoC) were available.

The objective of this work was to develop six different new low melting ternary (LMT) x Ti-yAG-zCu alloys (x = 50 or 60, y = 40 to 10, z = 10 - to 30) and evaluate: melting point, density and hardness of, as prepared LMT, Ti-alloy ingots.

Microstructures and phase identification using optical, SEM/EDS and X-ray diffraction. Corrosion resistance using polarization hysteresis and atomic absorption spectroscopy. Castability, goodness of fit, mechanical properties and reactivity with investments.

Results showed that all LMT Ti-alloys were found to have significantly lower melting temperature, and higher densities than pure Ti. Phase identification analysis shows intermetallic compounds' structure were found in all LMT Ti-alloys. Alloys containing 60 wt.% Ti were found to have spontaneous passivation comparable to pure Ti. Metal release results agree with the electrochemical results. The total cation release of all three elements in the worst conditions did not exceed 2.5 ug/cm² after six months of storage time.

Casting of the (60Ti-yAG-zCu) alloys exceed pure Ti in castability and can produce marginal fit comparable to pure Ti with better marginal fit than the most commonly used dental alloys, Rexillium III and Austena-37. LMT Ti-alloys were found to be less reactive with the conventional dental phosphate bonded silica investment (RemaE) that pure Ti.

Microhardness of LMT Ti-alloys were constant from the outermost mold-metal interface surface to the center of the cross-section. Tensile strength and ductility of the LMT Ti-alloys were significantly reduced from those of pure Ti but were equivalent to other dental alloys.

In conclusion (60Ti-yAG-zCu) alloys have excellent castability, chemical and acceptable mechanical properties that give them a great potential for future use as dental alloys.
Saudi Dental Journal 1994;6(SI)-Abstr.013:p14-15

014. Evaluation of the effect delayed management of traumatized permanent teeth

The present investigation was aimed to study the complication that could arise from delayed management of traumatized permanent teeth. Patients reported to the primary care clinic at the College of Dentistry, King Saud University seeking treatment of traumatized anterior teeth were evaluated. Aesthetic considerations (60 patients) and pain, swelling or discomforts (50 patients) were the main reasons of bringing the patients to the clinic. Clinical and radiographic examinations as well as history of the trauma were recorded. It was found that most of the patients had treatment delay exceeding one month. Initial pulp exposure resulted in 100% pulp necrosis. Enamel and dentin fracture showed a frequency of 53% pulp necrosis. External root resorption and pulp calcification were seen in few teeth. It was concluded that the figures for pulp necrosis could be misleading as there might have been a bias because only patients with problems showed up. In addition, a trauma awareness educational program should be developed to encourage parents and the public to seek immediate dental treatment. Furthermore, a proper diagnostic test for pulp and periodontal complication should be done in patients with initially non-treated dental injuries.
Saudi Dental Journal 1994;6(SI)-Abstr.014:p16

Saudm. Orfali,
Madinah Cental Center, King Fahad Hospital, P.O. Box 123, Madinah, Kingdom of Saudi Arabia.

Previous reports of solubility of root canal sealer cements involved specimens of (10 mm x 1.0 mm thick) whose size was analogous to that stipulated in contemporary specification tests for silicate and zinc phosphate cements. Such specimens greatly exceed the amount of materials used clinically for root canal filling.

In the present study, specimens of 5 mm diam x 1 mm thick were employed so that proportioning and manipulation of the constituents were clinically relevant. Eight endodontic sealer cements, N2 universal, AH26, AH26(SF), treatment spad, endomethasone (Ivory), tubil-seal, diaket A and diaket, were studied. Each specimen was immersed in a 5 ml aliquot of solution. Three types of solution were used: (a) deionized double distilled water, (b) water acidified with nitric acid to pH4, (c) water made alkaline by aqueous ammonia to pH 8.8 immersion period of 1 hour, 1, 3, and 7 days. All without change of solution were applied to samples of each cement. Weight changes in the immersed sample were measured and the filtered and unfiltered solutions were analyzed by Instrumental Neutron Activation Analysis (INAA). The weight loss of the specimens ranged from 1.1% for diaket to 25% for spad. The analysis of the filtered and unfiltered solutions indicated that 8a, I, Ti, Zn may be lost from the sealer by either dissolution or disintegration.
Saudi Dental Journal 1994;6(SI)-Abstr.015:p17