CLIAMS:1. The custom tray fabricated with MAXILLARY ‘M’ WAX SPACER FOR FINAL IMPRESSION MATERIAL IN COMPLETE DENTURE is to record secondary impression. This ‘M’ spacer prevents the pressure during impression making in the relieving areas of maxillary arch. The thickness of spacer wax i.e., 0.2mm will act as a space for the final impression material. Second layer of 1mm of spacer wax is adapted over the first layer that absorbs the stress which is applied during impression making and does not transmit it to the underlying bone. Thus, resorption of the bone is prevented. It also covers the crest of ridge which is readily resorbed with masticatory forces. Impression is recorded without any pressure in the sensitive areas. Therefore resorption of the maxillary arch is restricted very much. The total of 1.2mm of space is available to relieve the areas and for final impression material. ,TagSPECI:
FORM 2

THE PATENT ACT 1970

(39 OF 1970)

&

THE PATENTS RULES, 2003

COMPLETE SPECIFICATION

(See SECTION 10, RULE 13)

1.TITLE OF THE INVENTION :

MAXILLARY ‘M’ WAX SPACER FOR FINAL IMPRESSION MATERIAL IN COMPLETE DENTURE
2.APPLICANT

NAME : KRISHNA INSTITUTE OF MEDICAL SCIENCES

NATIONALITY: DEEMED TO BE UNIVERSITY DECLARED
U/S 3 OF UGC ACT, 1956 VIDE NOTIFICATION NO. F.9-15 / 2001 – U-3 OF THE MINISTRY OF HUMANRESOURCES
DEVELOPMENT, GOVT.OF INDIA

ADDRESS : KRISHNA INSTITUTE OF MEDICAL SCIENCES,
NEAR DHEBEWADI ROAD, MALKAPUR, KARAD, 415110, MAHARASHTRA, INDIA

3.PREAMBLE TO THE DESCRIPTION
PROVISIONAL

N / A COMPLETE

The following Specification particularly describes the nature of this invention and the manner in which it is to be performed :

4. TECHINICAL FIELD

The present invention is related to dental science (Dentistry) particularly to the field of Prosthetic dentistry. It is mostly related to the Complete denture Prosthodontics – a branch of dentistry that deals with replacement of all missing teeth with artificial substitute where patient can place and remove the dental prosthesis according to his/her wish. Our new MAXILLARY ‘M’ SHAPED WAX SPACER is to prevent stress over relieving areas and to provide space for secondary impression material in complete denture cases. Thus our spacer reduces the maxillary bone resorption (reduction in bone height) and maintains the health of maxillary edentulous arch (upper jaw without teeth).
5. BACKGROUND

The conventional complete denture (a removable prosthesis which replaces all missing teeth) is fabricated on the edentulous arches of upper jaw (maxillary arch) and lower jaw (mandibular arch).
In dental practice, negative replicas of oral tissue (impressions) of edentulous arches are recorded with stock tray (readymade tray) and thick primary impression material which is called Primary (first) impression. This primary impression is poured with dental plaster to get the positive replica of oral tissue (Cast). Various authors have suggested different designs to cover the relieving areas with wax spacer. On the poured primary cast, delicate relieving areas of oral tissues are marked with the copying pencil. The first layer of full spacer wax of 0.2mm thick is adapted on the primary cast leaving posterior palatal seal area and 4mm short of sulcus. This first layer of spacer wax provides space for final/Secondary impression material. Over the first layer of spacer wax (0.2mm thick), second layer of 0.2mm thick spacer wax is adapted on the primary cast. This second layer of spacer wax is adapted on the stress relieving areas of maxillary arch which provides relief to the stress relieving areas. The total thickness of (0.2mm+0.2mm) 0.4mm double layer wax is adapted on the primary cast. With these two spacers on primary cast, a custom tray is fabricated with acrylic resin which is 2mm short of the sulcus. The acrylic custom tray is utilized to record the final/secondary impression of maxillary edentulous arch. Before recording the final impression, both the spacer waxes are removed. This creates a space for final impression material. The custom tray loaded with impression material is inserted into the patient’s mouth and final impression is recorded. Then this impression is used for further procedure of denture fabrication.
The total 0.4mm of spacer wax is not sufficient to reduce the forces on the relieving areas of maxillary arch. Secondly, most of the times we get pressure spot in the special tray which indicates that soft tissue is pressurized by the force applied during secondary impression procedure.
DRAWBACKS:-
During impression making there is no control over the material and impression tray pressure, this pressure is transmitted as force over the rugae and underlying bone. Existing spacer did not consider the elevated fibrous rugae area. Also it causes distortion of rugae, which appears as pressure spots in the secondary impression.
6.SUMMARY

In ‘M’ spacer, the rugae area is cover with 1.2mm spacer wax, which provides the space for secondary impression material. This 1.2mm is adequate space for secondary impression material which absorbs the pressure applied on the underlying tissue. So there is no distortion on rugae and force is distributed equally on underlying tissues.
It is universal fact that crest of the alveolar ridge in the maxillary arch has more cancellous bone showing more resorption under load, so it should be relieved. Our ‘M’ spacer covers the anterior and posterior alveolar ridge with 1.2mm to prevent the resorption.
In the normal function during chewing with complete denture, masticatory forces/load, are transmitted to underlying edentulous ridges. There are stress bearing and relieving areas in the edentulous arch. The masticatory forces are distributed equally over the stress bearing areas and avoid pressure on the relieving areas during final impression making. Our special Maxillary ‘M’ spacer is made with anatomical consideration for custom tray over the primary cast. Maxillary ‘M’ spacer firstly provides relief to the stress relieving areas and secondly distributes forces over stress bearing areas with impression materials that records tissue details.
RELIEVING AREAS:- (The anatomical structure which cannot bear forces) In maxillary edentulous patient the relieving areas are (a) Incisive papillae (b) Mid-palatine Raphae (3) Anterior alveolar ridge (sometimes). During fabrication of special tray, 0.2mm full spacer is adapted over primary cast leaving posterior palatal seal area and sulcus 4mm short. Then 1mm spacer wax is adapted over the full spacer on the relieving areas. These spacers act as a stress reliever and provide space for secondary impression material. The forces over this area is absorbed and transferred to the stress bearing areas, in this way two layers of spacer wax relieves stress on delicate structures on maxillary arch.
Advantages:-
1] It covers all the areas which are sensitive to masticatory loads.
2] It relieves the stress relieving (sensitive) areas.
3] It prevents the resorption of underlying maxillary bone.
4] It provides sufficient space for final impression.
5] It records the fibrous tissue in undisplaced and undistorted condition.
6] Jaw bone is having tendency to resorb with age. The said invention will reduce the complaint of loose denture in short duration after fabrication.
7] It will maintain the size and shape of arch for longer period of time as resorption is prevented.
8] It preserves the health of maxillary anatomical landmarks.
7. BRIEF DESCRIPTION OF DRAWINGS:

Fig. 1 shows top view of primary impression of upper jaw (maxillary arch) without any teeth (Complete edentulous arch).

Fig. 2 shows top view of Maxillary edentulous cast with 0.2mm of spacer wax is adapted.

Fig. 3 shows top view of Maxillary edentulous cast with adapted 1.2mm of spacer wax.

Fig. 4 shows the cross sectional view of maxillary primary cast with adapted wax spacers.
8.DETAILS DESCRIPTION OF DRAWINGS:

Fig. No. 1 shows top view of primary impression of upper jaw (maxillary arch) without any teeth (Complete edentulous arch). It shows the normal anatomical structure of the maxillary edentulous arch. Maxillary arch consists of relieving areas (which cannot bear the forces) and stress bearing areas (which can bear the forces). The relieving areas in maxillary arch are crest of anterior alveolar ridge [1] incisive papilla [2] Rugae area [3] Mid-palatine raphe [4]. In our spacer design, spacer wax covers the relieving areas of maxilla and crest of posterior alveolar ridge [5]. These areas are marked with the copying pencil. Other anatomical landmarks are labial sulcus [6], buccal sulcus [7] and posterior palatal seal area [9].
Fig. No. 2 shows top view of the Maxillary edentulous cast with marking of relieving areas. Over the maxillary cast, spacer wax (Pink coloured) [10] of 0.2mm thick is adapted on the primary cast. The spacer wax should be 4 mm away from the labial and buccal sulcus [6 and 7]. This spacer wax should not cover the posterior palatal seal area [9]. That means spacer wax should cover the primary edentulous maxillary cast except sulcus and posterior palatal seal area. The excess spacer wax is cut with sharp instrument. This spacer wax which provides space for the thin consistency final impression material is known as full spacer.
Fig. No. 3 Shows top view of Maxillary edentulous cast with 0.2mm of adapted spacer wax. Over this spacer wax [10], second layer of 1mm thick wax is adapted on the primary cast. This second layer of 1mm thick modelling wax which is red in coloured adapted on the relieving areas [1 to 6] of primary cast is known as relieving wax [11]. The extra wax is cut with the sharp instrument till the marking done relieving areas on the cast. After cutting the excess relieving wax, it appears as letter ‘M’ hence we term it as ‘M’ spacer wax. The combined thickness of both the spacer and relieving waxes are 1.2mm. This thickness of wax will provide sufficient space for relieving areas and the final impression material. The 1.2mm space does not apply any pressure on the relieving areas during final impression procedure.
Fig. No. 4 shows the cross sectional view of maxillary primary cast [12]. It shows the spacer wax (Pink coloured) [10] of 0.2mm thick covering the maxillary cast. The modelling wax (Red coloured) [11] of 1mm thickness covers the spacer wax. The total thickness of both (spacer+ relieving) the waxes are 1.2mm. In cross-section fig no 4 it shows that the both the waxes is 3-4mm short from the labial sulcus [6] and not covering the posterior palatal seal area [9].

9.I claim

1. The custom tray fabricated with MAXILLARY ‘M’ WAX SPACER FOR FINAL IMPRESSION MATERIAL IN COMPLETE DENTURE is to record secondary impression. This ‘M’ spacer prevents the pressure during impression making in the relieving areas of maxillary arch. The thickness of spacer wax i.e., 0.2mm will act as a space for the final impression material. Second layer of 1mm of spacer wax is adapted over the first layer that absorbs the stress which is applied during impression making and does not transmit it to the underlying bone. Thus, resorption of the bone is prevented. It also covers the crest of ridge which is readily resorbed with masticatory forces. Impression is recorded without any pressure in the sensitive areas. Therefore resorption of the maxillary arch is restricted very much. The total of 1.2mm of space is available to relieve the areas and for final impression material.

Dated this 4thDay of January, 2013

DR.M.V.GHORPADE
(REGISTRAR)
FOR KRISHNA INSTITUTE OF MEDICAL SCIENCES

To
The Controller of Patents,
The patent office,
At Mumbai – 400 037

10.ABSTRACT OF THE INVENTION

The MAXILLARY ‘M’ WAX SPACER FOR FINAL IMPRESSION MATERIAL IN COMPLETE DENTURE is a wax spacer on maxillary edentulous arch considering the resorption pattern and stress distribution in maxilla. In this, two different thickness of spacer are used and adapted in two steps. First layer of 0.2 mm spacer wax covering the whole maxillary arch and keeping 4 mm short of sulcus. Over that second layer of 1mm thick wax covering only the crest of ridge, the buccal and labial slopes of the ridge, incisive papilla and mid palatine raphe is adapted.
This design will overcome the resorption pattern of the maxilla and distribute the stress only on stress bearing areas in the maxilla which will benefit to the overall prognosis of the arch and well-being of the patient.

DR.M.V.GHORPADE
(REGISTRAR)
FOR KRISHNA INSTITUTE OF MEDICAL SCIENCES